Towing in OD w/4.10s

[rick87K5]

Hello all,
Next time I will be sure to be more specific in the subject line; didn't mean to provoke anything here. Steph, thanks for the owner's manual transcription. I meant to check mine this morning but didn't get a chance. I certainly do appreciate everyone's input. Thanks.

Rick

 

[CaptCrunch]

You can tow in OD w/ a 700R4, but you need to make some modifications to the tranny to upgrade the weaknesses. The tranny is flat out not made for towing in od and in fact the downshift pattern and stiffness if valved different fo D then OD because of it. Anyway you go... why risk blowing a $1500 tranny for and extra $5 in gas. If you tow regularly I would definetly say swicth to a 400 or 4L80

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>

 

[azblazor]

Hey man, nothing to take it easy about. I made a post about my experience with an overdrive transmission and I identified what kind of transmission. Then Rene made an overly obvious post about what a 4L80E was and was not. As if I somehow did not know that, or as if I should not have posted my experience. Well that deserves a DUH, in my opinion. Then of course Steph comes to the rescue of Rene, (like he needs it). Of course she has a " typo" and an erronous statement (maybe also a typo) in her reply / defense of Rene. So that deserves a Duh also, in my opinion.

I entered this thread merely to convey my experience with an OVERDRIVE transmission, towing heavy trailers with 4:10 diff's, for extensive mileage.

So in closing Chris, I own 2 different trucks with 4L80E's in them, for the really uninformed ( and for Rene and Steph), that means they are turbo 400 electroniclly controlled overdrive transmissions. They ARE NOT turbo 350 overdrive transmissions (either mech or elec controlled - 700R-4 or 4L60E). And I'll even give myself a DUH here (for 1. - stating the obvious, and 2. - to even the "duh count" , I certainly wouldn't want Miss Steph to think me immature).

And one more thing, neither of MY 4L80E's have (or had) factory temperature gauges. And neither of them have "tow-haul" mode (one is a 1993 and one is a 1994). I believe some of the very latest production trucks may have temp guages for transmissions, I've never seen one though. I know that the newer Allison transmissions have tow-haul modes, but I've haven't seen one either, and I've never seen a 4L80E with a tow-haul mode- but again, they may certainly exist.

<font color=blue>azblazor</font color=blue>
<font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>

 

[dyeager535]

I'd like to see someone step in and say why the 700 gets hot running in OD. (someone that knows these trannies) You are completely eliminating torque converter "slippage" (D is the same way) which is what causes heat in an automatic tranny. Thats why higher stall converters are hard on trannies. Its not the other way around.

Now, there MAY be a problem with the way fluid is routed to be cooled when in OD, IIRC, I had heard that it is routed from the PAN to the cooler when in OD, (or was it when the converter was locked up) which is just plain silly, since the heat doesn't come from the pan. Again, not being a tranny guy, IIRC, in all other gears, the hot fluid out of the converter goes straight to the cooler. But I'd like someone that understands the fluid routing diagrams for the 700 to explain it.

Although the OD clutches are fewer in number and size than the other packs, if you aren't towing a LOT of weight, and have the gearing to match, it really shouldn't be a problem. Gear hunting is one of the main problems, as would be, with the fewer/smaller clutches in OD, lugging the engine. Don't let the engine bog down, and you will be fine. If you have to press the pedal far enough that it downshifts, you need to be in D, not OD.

In any case, throw a tranny cooler on there.

Dorian
My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
Why insist on counting when the ring gear has the tooth counts stamped in?

 

[tRustyK5]

Mark, my post was written in haste...

I'm sure you are well aware of which tranny you have...but not everyone here knows the diference between the 4L60, the 4L60E, the 700R-4 and the 4L80E. My reason for 'stating the overly obvious' was that someone that doesn't know the diference between the 4L80E and the 700R-4 may infer that towing with their 700R-4 in OD is a good idea because you had such a great experience. So clearly stating the difference between transmissions was for their benefit, not yours.

Rene...duh

<font color=green>Dyslexics of the world...UNTIE!</font color=green>
<a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>

 

[azblazor]

Rene,
Thanks for the clarification. Not to belabor the point (well actually, we both have a tendency to do that), but when you wrote only these words:
<font color=red> quote:4L80E is not a 700R-4...it's a TH400 with an overdrive. There is a huge diference in strength and longevity between the two tranny's. Rene </font color=red>,
it seemed to me, at the time (zero dark thirty), that you were somewhat, just a tiny bit, telling ME that I'm an idiot, in so many words.
So again thank you for your wonderfully courteous reply. As far as Steph goes, I thinks she is enamored with you. So I fully appreciate her taking some issue with my seemingly disrespect of the truly revered, "Great One of the North".

Yours in duh-ness,
Mark

PS, how's work situation?

<font color=blue>azblazor</font color=blue>
<font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange><P ID="edit"><FONT class="small">Edited by azblazor on 10/18/01 07:59 PM.</FONT></P>

 

[84_Chevy_K10]

I'm with CaptCrunch, as I have noticed that my tranny shifts way differently in 3rd than OD.

You're crazy if you tow in OD with a 700. I don't care what you've done to it. 700R4s weren't made for towing at all, much less in overdrive with weight behind you.

In my not so humble opinion, you're nuts if you tow in overdrive. In fact, if you didn't have the 4.10 gears, I'd say you were nuts for pulling with a 700R4, period.

I have a 700R4, I tow with it, and I stay OUT of overdrive.

And I find it hard to believe that GM ever said that you could tow in overdrive with any 1/2 ton or similar vehicle. I've never read that.

4L60E and 700R4 are basically the same tranny, just one is shifted electronicially.

I wouldn't tow in overdrive with either.

Tim
'84 Chevy K10, lifted, loud, fast, and 3/4 ton axles

 

[tRustyK5]

<blockquote><font class="small">In reply to:</font><hr>

it seemed to me, at the time (zero dark thirty), that you were somewhat, just a tiny bit, telling ME that I'm an idiot, in so many words.

<hr></blockquote>

It was my bad...it was late and I should have been more clear the first time.

<blockquote><font class="small">In reply to:</font><hr>

"Great One of the North".

<hr></blockquote>
I thought that was Wayne Gretzky?

Rene

<font color=green>Dyslexics of the world...UNTIE!</font color=green>
<a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>

 

[azblazor]

Wayne Gretzky? Oh.. that guy who just became part owner of the Phoenix Coyotes. He was from Canada?

<font color=blue>azblazor</font color=blue>
<font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>

 

[Blazr77400]

If a 700r4 has been updated with the newer stuff, and built by a person who knows what they are doing, then you will be okay towing in overdrive. I have 35's and I tow all the time. I tow a Enclosed snowmobile trailer with four snowmobiles and all the gear, including the weight of my truck, which is heavier then a blazer. I tow it up fairly steep grades to. I have a trans temp guage. Has never been hotter then 190. The trans never fights for gears. Every time I change my fluid it looks great.
Pulling with a Stock 700r4 I wouldnt do. Pulling with a modified 700r4 I believe you will be okay.
When I first bought my truck the trans had been rebuilt 2 or 3 times. They never got it right. 6 months later it blew up. So I had A guy who has been rebuilding transmissions all his life build me one. Have not had a problem since.
The 700R4 IS ONLY AS GOOD AS ITS BUILDER!


4 wheeling is like sex, when its good, its really, really good, when its bad its still pretty good.

 

[Thunder]

I kind of resent being called "crazy and nuts" As i stated in previous post" I tow in OD with no ill effects". I have had the pan off my 700r4 many times and found it clean as a whistle. I have towed my boat and other trailers many thousands of miles in the hot desert summer. My tranny if fine . I have a firend who tows a big ol 5th wheel with his K2500 with a 700r4. His trany is holding up well. he uses OD when towing also. I have another buddy who hauls around a huge overhead camper in a K2500/700r4 It never comes off his truck.No tranny problems there either. I know many people who have 700s and beat the hell out of them. The only person I know of who blew one. Had one behind a 454 in a 4x4 flatbed he used to haul drill rod around in.It was always overloaded and the guys who worked for him raced the heck out of it. And went 150000 miles before it blew.
I guess all these people are nuts too. Maby we are all stark raving lunatics.
To listen to some of you people talk around here you think the 700 is some kind of a shabbly built thing that will blow up if you look at wrong.
But I have found quite the oppisite is true. it is a good reliable tranny if cared for properly.
Fresh clean fluid is a must. Heat runis 700s because it breaks down the fluid and it looses its lubrication properties rapidly. 700s must have fresh clean fluid or they will blow. If your fluid is the slightest bit discolered it should be changed. You shoud have a good cooler too.
Well I gotta go now.................. Here come the men in the white suits again..........................


<a target="_blank" href=http://coloradok5.com/gallery/Thunders-Blaze>http://coloradok5.com/gallery/Thunders-Blaze</a>
<font color=blue>NEVADA: Where the pavement ends, and the West begins.</font color=blue>

 

[CaptCrunch]

the overheating issue in od...

The number one killer of the 700 is obviously heat. In the 700 heat is caused by 2 major items... 1.constant cycling of the tc and shifting up and down... 2. lugging of the engine and not allowing the converter to enguage... thus allowing slippage. I read alot of posts here that said you had to be going at least 2000 rpm at freeway speeds or you'd kill the 700 and blah blah blah... that isn't necessarly true. To set the record straight it all comes down to the tc locking up and STAYING locked up. (If you aren't familar with lock up tc's... the lockup allows the converter to become much more efficient. This reduces heat... increases gas milage, etc. A non-lockup type converter would never be able to be at the exact same speed as the engine. The small difference in speeds of the engine and trans wastes power and creates heat) Ok so we have established the converter needs to be locked up and not slipping or heat will build up. Now lockup is totally different on each vehicle... it varies depending on the converter stall speed, the power of the engine, gear ratio or the rear and tranny gears, tire size... etc. My guess on the how the whole issue begun was w/ the trucks equipped w/ 3.08 gears. Every truck I have looked at w/ 3.08 gears came from the factory (as listed in the doorjam and/or glove box sticker) w/ a smaller sized tire... I can't remeber the size, but something pretty weeny like a 235. Obviously that looks lame so lots of dealers and/or people put on a more reasonable 31 or 32 inch tire.Even though the difference was very slight it probably made for a lot more slippage because the 3.08's were probably cutting it very close to the danger zone if not already in it from the factory. Bare in mind that the 700 was one of the first real experiences w/ overdrive and not too many years before the first 700 they had just begun using a lockup style converter. Again this is just kinda a theory on my part... so if anyone wants to add to it or rip on it feel free

I won't claim to be any tranny expert, but one of my good friends partly owns a transmission shop and does all the rebuilding of their 700's. He has modified 700's for many different applications including towing, mud trucks, drag cars, and street rods. His current street rod is a BBC that puts out over 500 hp at the rear wheels and is driven hard both on the street and at the strip. So since it is a 700 behind it I would say he knows his stuff... What he has told me is it isn't a heat build up issue while towing... it is the strength of the overdrive parts along w/ the some other items such as the sungear shell and sprag. All the 700's have some pretty weak components in them... thus this is why you shouldn't put a shift kit in one unless it is modified. Overall he says the 700 isn't much more heat sensitive then a lockup style 350, but it is much more PRONE to being in the position to create heat and kill itself.

Seems to make sense to me. I do have to say that most tranny shops don't know enough about 700's and you really have to be careful who rebuilds them Returns and comebacks are very common on the 700's as lots of places attempt to update and improve them, but in actuality cause more problems.


-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>

 

[Leadfoot]

Hey man

, there is something to take is easy about

. There probably shouldn't be, but with all the stuff that has taken place on this board recently, I feel there is. We are all trying to help each other. With people like Buttman and Fartman around it gets a little annoying. But because of them, it is sometimes hard to tell whether people are being light hearted or mean when they make a witty reply (i.e. Executioner, although he means well). As has been noted in several posts, there have been some pretty heated debates (which is not always bad), but when somebody offers advice or makes a statement (which sometimes MAY be wrong), it is best to let them know why it is wrong/incorrect rather than saying "DUH". And not that saying DUH is necessarily wrong, but if you mean it light-heartedly then post a

or two (that's what they are there for). From what you wrote, I understand your meaning (and is appropriate), but when I first read it with no context, I thought you were being rude to Steph and Rene. Now I know better

. I apologize if I seemed a little rude.

***background info***

For everyone with 700's I have done some research (local tranny guy) and the reason the 700's overheat when towing in OD (even with converter locked), is that the mechanical advantage the load has over the tranny, causes the bands and clutches to slip (this is where the heat comes from, not from converter slippage). By using higher quality bands, fresh fluid, properly adjusted TV (a little firmer than stock), and using aftermarket billet servo's (more holding force), and a larger than stock pressure valve (I think it's .5 or .05 inch orafice size) you can create more holding force for the bands and clutches. Even with all these mods you can only create so much holding power, and with a big enough load, that holding power can be overcome (that's why even the pro built 700's say 6,000 pounds of trailer weight is the safe limit). Because the 4L80 is a physically bigger tranny, they have wider/thicker clutch packs and bands (plus fluid pressure is matched), so it can hold a heavier load in OD (or any gear for that matter). The reason shifting to D from OD can help in any trans, is the mechanical advantage of the load is decreased. Just like changing gear ratios in a rearend from 3.08 to 4.10.

Also too, because the 4L80 is a heavier/stronger unit, it requires more horsepower to turn, so the amount of HP loss from crank to rear wheels in more than that of a 700r4, but I was told that the amount of difference is negligable.

As Brian stated, for some a 10 bolt is More than enough, and for others it won't last a day. Same with trannies, it all depends on how you use it. Some may need a 4L80 because they tow heavy loads, but some may not if they are just towing occasionally or lighter loads. If you don't do much towing or tow light trailers, a 700 may be more than enough. It's the same issue of 10 bolts vs. D60. Cost vs. need. D60 cost alot more than 10 bolts and 4L80 cost more than 700r4. If you don't need the beefier unit it's a waste of money, but if you do, then it's a good investment (rather than buying the weaker unit first only to break it in short time and need the stronger unit).

See my rig at <a target="_blank" href=http://coloradok5.com/gallery/Leadfoot>http://coloradok5.com/gallery/Leadfoot</a>

 

[dyeager535]

Yes I should have clarified...the lock up is what I'm talking about. You should THEORETICALLY generate more heat in 1st or second, since in those gears the converter can never lock. Even stock, most running around in 3/4 is done with the converter locked, and stock, the converter lock (without tach) is transparent.

I don't know as I agree to the heat not being an issue. These trannies are still being used (I'm assuming that internally/mechanically), they are still VERY much the same..I know about the electronics difference, but the clutch/bands/drum arrangement is what I am talking about. "Hard" parts. If you look in a tranny parts catalog, you will see that there are actual tools made to remove parts that are WELDED together from heat. If parts are welding together, thats heat. (believe it was a planetary)

Now, what I will say is that the later the model, the better it will be. The first ones are going to be poor. The bugs aren't all worked out, and thus, you have tranny problems with 4800lb vehicles and 3.08 gears. Hardened parts come up, minor things are tweaked, etc.

My friend, during racing season, uses his 88-up (no clue year) 1/2 ton (700/4L whatever) to tow every other weekend Some journeys 1000miles, over the Cascades. With his car, tools, trailer (the thing is heavy enough for a bulldozer) he is easily at or above the 6000lb mark. And he tows in OD. I've towed with that combo before as well, and with 3.73's, it's fine.

I'm going to blame most problems on the OWNERS of the vehicles. Talking about lugging the engine, lock/unlock, etc., thats because people are TOO ACCUSTOMED NOT SHIFTING. If you try and tow up a mountain pass, with a manual tranny, 6000lb load, 454, 10" clutch, and just leave it in 4th up a hill, you will fry the clutch, if you even make it up. People must think that an automatic somehow knows what the terrain ahead is, and figure the tranny is going to know what to do. That MAY be well and good for a lightly loaded (or light in general) vehicle with decent gearing, but waiting until the engine is lugging, vehicle speed has already dropped, and the gas pedal is to the floor, is not the time to shift.

Not sure what you mean lockup is different. Lockup is lockup. The converter is locked or its not. The load on the converter BEFORE it locks up can make a difference, but locked up is locked up.

I also don't agree with "All the 700's have some pretty weak components in them". Although OD IS a "weak" gear, there are far too many vehicles running around now with 100k plus trannies in them, to call the internals weak. Weak for loads they were not designed for? Yes. Weak for what GM deisgned them for? No. Thats why GM goes 4L80E when its needed. GM makes CONSTANT improvements on these things, and every consecutive year will be better and better. You will see that certain "new" designed parts, such as pump valves, are recommended or demanded, during rebuilds of earlier units.

Saying the 700/4l60/4l60e is a weak tranny is bad form. (not you Cap'n) There are ALWAYS good and bad stories about anything, but if it WERE that bad of a tranny, and couldn't have been improved or fixed, GM would not keep that tranny in its line up. Which they have.

Dorian
My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
Why insist on counting when the ring gear has the tooth counts stamped in?

 

[Leadfoot]

Capt., I can understand what you are saying, but have to disagree. If it all came down to converter lockup then you would not be able to tow with a 400 or 350 because their converters never lock-up and from what you say heat would constantly build to the point of failure. I will agree though that if a lock-up trans is lugged while the converter is locked, it will cause the small (read tiny) clutch inside the converter to slip. This alone will not generate a tremendous amount of heat, but over time it will lead to "converter shudder" (basically a worn out converter clutch). As for the weak points being hard parts, well yes and no. The hard parts of a 700 are not as strong as a 4L80, but that is not the reason MOST (some do) fail. If you lose an input sprag or sungear shell, your tranny is toast (no go). In reality most 700's start to slip or mis-shift (just look at the hundreds if not thousands of posts on this board from people with ailing 700's). Hard parts can break in a 700 (I'm not saying they can't), but it is not likely unless you have NO2, or do alot of full throttle shifts from R to D. All the posts of slipping or slow shifting, are not a hard part failure but rather a clutch pack or band gone bad (or sometimes a bad valve body).

I will agree that since it was GM's first attempt at an overdrive, they had a lot of bugs to work out. Also as you say the gear ratio and tire size played a role. As tire size increased (people wanting more ground clearance), the leverage placed on the tranny not only by the poor (usually 3.08 gears), but also due to the tranny crippling itself with a .7 disadvantage with OD lead to too much force (especially during shifts or towing) for the bands and clutches to hold. Even if you didn't tow, you still had a slightly longer delay between shifts (which eats clutch/band material), over a period of time it would take it's toll and cause the tranny to slip longer and longer (causing more and more heat), and given enough time...Bad tranny. If you notice even some of the performance shops don't put in stronger hard parts (some do for added insurance), but they all use better clutches/bands, and they all use better servo's and pressure valves to help the bands/clutches hold. These trannys are better for towing because they have a hardened input sprag, or sungear, they are better because they have more holding power. The ones that have better input sprags and such are still better yet, but those components mainly come into play during hard launches and jolts. This is from a tranny guy who builds just about every tranny (manual or auto) for our truck pullers. See the picture of my rig below and ask whether or not it is stressed (it is a 700 with the stock input sprag and sungear). Granted in that picture I am not pulling a trailer in OD, but that sled weighs 45,000+. I also tow my buddy's unregistered old F350 to the pulls on a car trailer on the highway in OD to the pulls. His truck alone when we put it on the scales is 6,200 and that is not the weight of the trailer.

See my rig at <a target="_blank" href=http://coloradok5.com/gallery/Leadfoot>http://coloradok5.com/gallery/Leadfoot</a>

 

[blazbrnc]

I work in one of the plants that makes the 4L80 transmission along with a bunch of transaxle trannies. I supply all of the tooling (drills, reamers, broaches, etc.) that make these transmissions. Before this job, I worked directly for GM Powertrain for 7 years in a transmission test lab as a test engineer. I have tested all of Powertrain's transmissions in one way or another (dyno tests, component torsional tests both dynamic and static, FEA, and static stress analysis). One of my jobs was to determine why transmissions had failed in the field. That being said, here's one of the issues that caused customers stranded quite often (not good as far as Power train is concerned): Problem #1: Overheated trans caused by towing in OD. Slipping clutches heat up. They contaminate the fluid which in turn plugs valve body and pumps. Also, the oil starts to boil out of the vent or filler tube. I don't know about anyone else, but up here in relatively flat Michigan I have seen quite a few trucks towing trailers of some sorts that are either blowing a bunch of smoke out the back or already parked on the side of the highway. That is caused by an overheated tranny. I tow my blazer with my 4L80 equipped suburban. I have and never will tow in overdrive. I know there has been a lot of proof that a tranny may last towing in OD, but why take the chance?
As for GM always upgrading to the best possible components, no way. Powertrain is in the business of making money. You can't make money by changing components from year to year. Except for a few casting changes, the transmissions today (4L80 and 4L60 at least) are the same as when they started making them in the late 80's. GM will change when failures in the field cause them to. But, GM is making a HD 4L80 right now in limited production that has a few internal upgrades.
I have a '99 4L80, no temp gauge, no tow/haul mode.
Overdrive is an afterthought in the 700R-4. It isn't designed to tow. The reason it doesn't need to be as beefy as 1st through 3rd gears is because it is designed to maintain speed. In other words, the torque of the motor is what gets it up to speed, at the speed that OD should kick in torque is greatly reduced.
Towing in OD is asking for trouble in my experience.

'79 K5, '79 Suburban, '76 Br**co, 77 K20
'99 BB 4x4 Suburban to tow more junk home

 

[riz]

<font color=purple> After reading all of the replies to this post, I will NOT ever tow in OD ! I've heard enough to convince me !!

L8r,
. Riz . <a target="_blank" href=http://www.geocities.com/rizmonkey>www.geocities.com/rizmonkey</a>

<font color=purple> BOW CHICKA BOW WOW !

 

[dyeager535]

"As for GM always upgrading to the best possible components, no way. Powertrain is in the business of making money. You can't make money by changing components from year to year. Except for a few casting changes, the transmissions today (4L80 and 4L60 at least) are the same as when they started making them in the late 80's. "

You said it right there. LATE 80's. There were a lot of changes the first (6?) years of those trannies. I know GM won't put in the best parts, its actually the cheapest part that will keep the vehicle from coming back to the dealer under warranty. Obviously there were concerns "early" on, or things such as servos, pump valves, pump rotors and vanes, and hardened parts would not have come into play.

If GM doesn't want these vehicles back under warranty, from towing in OD, maybe someone should consult a 1/2 ton owners manual for the different years, up to present.

Dorian
My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
Why insist on counting when the ring gear has the tooth counts stamped in?

 

[azblazor]

DUDE! all this trany experience and knowledge - you been holding out on us. I still tow with my 4L80E in OD.


<font color=blue>azblazor</font color=blue>
<font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>

 

[azblazor]

Hey Man, DUH.........oh I almost forgot

<font color=blue>azblazor</font color=blue>
<font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>