What would cause a 700R4 to run hot?

[Hossbaby50]

My coolers aren't run threw the radiator anymore. I must have overtightened the fittings on the radiator and cracked the tranny cooler inlet so it leaked fluid all over.

I never really liked the idea of the cooler going threw the radiator but my tranny guy said I should leave it run threw the radiator probably for the reasons you mention. I am not so much worried about the summer and it getting hot enough but more about the winter. I know on a cold winter day it can take the fluid awhile to come up to operating temps.

I personally have not had a problem with not running threw the radiator and I know a few other people who don't either. My truck isn't a DD anymore though.

Harley

 

[ryoken]

Without the radiator cooler the tranny will run too hot in the summer and too cold in the winter and without reaching a temp of about 160-180* the tranny can't burn off any condensation within the fluid and water will kill a tranny.

Yeah, I've heard you say this before.. I'm not questioning the difficulty in warming up in the winter..

But as far as too hot in the summer? No way man... If I beat my truck silly in 100 degree weather, it'll reach 180.. General operating temps thruout the summer are 160 to 170.. And I'm not even stacked plate, I've got tube/fin...

 

[4X4HIGH]

Well, if you're not running too hot in the summer and not too cold in the winter then you're the exception to the radiator cooler. If you do run too cold in the winter you could always install a T-stat and hook the radiator cooler back up along with the external and that would allow you to not worry about winter time temps.

 

[ryoken]

Not to be a prick, but what is this theory behind "too hot in the summer"? You've yet to explain why this would be, and it's the first time I've ever heard it said..

My story is consistent is with many I've heard in here with the same setup, tough to warm up in winter and perfect temps in summer... Have yet to hear of a tranny running too hot from that setup...

Don't mean to nitpick this, I'm actually gonna go back thru the rad before winter myself.. Takes too long to warm up for my liking in cold weather... and if it raises summer temps 10 degrees, that'll be fine...

 

[4X4HIGH]

By too hot i'm talking anything over 200* for an extended period of time. It will vary with every rig since there are many factors to consider when dealing with tranny temps. Weight of vehicle, gearing, A/C or no A/C, 3 core or 4 core radiator, stall convertor or not, built tranny or factory. All of these things can and will make a difference in the resulting temps the tranny will see.

 

[ryoken]

Ummm, I understand all that...

But why would a "cooler only" rig run over 200? You don't have the rad heating it up to 210 initially, I just don't see the logic and would honestly be surprised to see it, no matter what truck config......

Heck, my engine oil temp will be rocking at 230, 240 when I'm beating on it, but the tranny has NEVER gone over 180..

 

[4X4HIGH]

If you can understand that the tranny temp runs hotter than the coolant temp then you would understand why running it through the radiator cooler would cool down the tranny. i don't know how to make it an easier for you to understand. Like i said earlier, there are many factors to consider when trying to keep your tranny cool. I'm sure there are some people who don't run the radiator cooler like yourself and don't have any troubles, (or so they say) but i'll bet their rig is on the stock side as far as tire height, factory trans (no shift kit, or stall convertor) factory axles not adding a bunch of weight with 14ff or D60 axles and such.

 

[ryoken]

ugh, no offense, but I feel like I'm talking to a democrat who keeps changing the subject.. You've yet to answer the question...

Yes, running thru a radiator will run cooler as opposed to say, running thru a closed loop... obviously... But it also heats it too, bringing it up to antifreeze temps.....

I've yet to hear the explanation why running it thru a cooling component that heats the fluid will make it run cooler than just running thru an isolated, non-heated cooling component...

I thought this was all pretty common knowledge around here... Been discussed numerous times and I pay attention... I'm sure if I search, I can find a 1/2 dozen to dozen people with similar results to mine... And none that have "cooler only" systems that have overheat issues... My truck is no fluke, but the norm from everything I've heard around here... Yeah, I'm not running a 3500 stall, but who is in our rigs? Other than some balls to the wall mud rig...

 

[4X4HIGH]

ugh, no offense, but I feel like I'm talking to a democrat who keeps changing the subject.. You've yet to answer the question...

Yes, running thru a radiator will run cooler as opposed to say, running thru a closed loop... obviously... But it also heats it too, bringing it up to antifreeze temps.....

I've yet to hear the explanation why running it thru a cooling component that heats the fluid will make it run cooler than just running thru an isolated, non-heated cooling component...

I thought this was all pretty common knowledge around here... Been discussed numerous times and I pay attention... I'm sure if I search, I can find a 1/2 dozen to dozen people with similar results to mine... And none that have "cooler only" systems that have overheat issues... My truck is no fluke, but the norm from everything I've heard around here... Yeah, I'm not running a 3500 stall, but who is in our rigs? Other than some balls to the wall mud rig...

What is it you can't understand about the tranny fluid running hotter than the engine coolant without any cooler? Now if you run the tranny fluid through the radiator cooler which is cooled by engine coolant it will make the tranny fluid run cooler. Now in the winter time when things are nice and cold it will bring the temp up faster so your tranny will work properly and stay alive by burning off the condensation that forms.

Do me a favor, disconnect your cooler lines from any cooler and hook them together so you do not have any cooler in the system and then come back and tell me how hot that fluid is getting, this should explain things.

 

[ryoken]

I should really just drop this... but I can't....

Here's what I said

Yes, running thru a radiator will run cooler as opposed to say, running thru a closed loop... obviously... But it also heats it too, bringing it up to antifreeze temps.....

please, don't talk to me like I'm stupid..

And you don't need to repeat again the condensation point, I've stated it numerous times in here, including a similar thread weeks ago...

I just wanted to hear evidence as to why a cooler only system would not cool as efficient as the radiator... Guess you have no evidence.... I certainly have evidence to the contrary...

edited for rudeness... long week....

 

[Pookster]

Since nobody's explained....

the in radiator cooler is a liquid to liquid heat transfer device, which is more efficient than a air/liquid cooler.

There are many factors that pull into this equation of course, some of which depends on your setup and conditions.

If your engine coolant is at 200, and your tranny is at 180, the coolant will heat the tranny up to 200. Simple as that.

Any cooler is only able to heat and cool to the limit of its equalibrium. If the outside temp is 140 degrees, your engine/tranny could not cool any lower than 140. There would be no way for it to shed any more heat than that.

So why is it recommended to run it through your radiator rather than a stand alone coolers?

1. The overall operating temp of the tranny is designed to be operated, somewhere in the vincinity of the coolant temp at the radiator (which is cooler than that of the engine temp. So if your engine is reading 210, most likely your radiator is significantly lower). As such, the in radiator tranny cooler helps equalize the tranny temp to the operating specs. The liquid to liquid cooling is very quick compared to air to liquid. Its important to add " of the same size core"- And as such, a small air to liquid tranny cooler cannot pickup or release heat as fast as the same sized liquid to liquid cooler.

So while this is how it is designed, sometimes the tranny gets taken out of spec- hard driving, age, slippage, towing, hills, etc etc... will cause the tranny fluid to reach higher temps. These higher temps, when it passes through the radiator, the radiator will acutally try to absorb as much heat as it can. However, it often cant take enough of it out in that single pass, and as such, we put in auxilary coolers- running an air to liquid supplimental to take it down another notch before returning the fluid. The amount of cooling that the air to liquid cooling can do is based upon a number of factors such as:

1. fluid temp
2. air temp
3. air speed
4. fluid speed
5. surface area/design (stacked plate vs tube and fin + overall area).

Some blend of these factors will determine how much lower (or higher) the temps will become.

It may be easier to understand if we reverse the process. Assume you park your truck outside. Its -20 out. eVery fluid is at that temp.
You move the truck inside to a 85 degree heated garage. Everything starts absorbing heat (instead of being a cooler, its now aheater!) until it equalizes with the room.

Does this mean your stand alone cannot cool as well as one which goes through the radiator? Absolutely not. It depends on those factors listed above. Im sure if you run a big enough tranny cooler, it will be even cooler than running it through the radiator + cooler.

 

[4X4HIGH]

Thanks pookster for clearing this up.

This thread was going to get me in trouble if it continued much longer. ryoken says i shouldn't talk like he was stupid but that seems to be what he was doing to me instead. I even went as far as to tell him that there are many variables to consider but he just seemed to not even listen to that part of what i said.

 

[ryoken]

None of what he just said, proves your point.. Air to Fluid, vs Fluid to Fluid transfer, yada, yada, etc..

BTW, noone here knows better that a fluid to fluid cooler is more effective than me. Sheesh, I work on raw water cooled heat exchangers every freakin day for coolant, intake air, oil and tranny fluid, don't think anyone else does...

But thats vastly different than having the choice between basically, a heat exchanger, in that sense of the term, where coolant heats the fluid and an isolated air-cooled option...

If your engine coolant is at 200, and your tranny is at 180, the coolant will heat the tranny up to 200. Simple as that.

Hmmm, gee, what have I been saying all along... Guaranteed, if I add my radiator to my equation, my temps are gonna go up from 170 to 190....

Does this mean your stand alone cannot cool as well as one which goes through the radiator? Absolutely not.

Sounds like what I, and all other posters with the cooler only setups have said all along.... When someone comes in and says they have a cooler only that runs hotter than a thru-rad setup, I'll admit I'm wrong, but till then I've yet to see any evidence to the contrary...

Heck, TCI goes as far as to actually recommend "cooler only"... Anyone with a BTO setup know what they recommend?

 

[Pookster]

kudos to you Ryoken. You know I respect your experience and knowledge.

Im just like to reiterate that there is certainly some porportion for the given transmission cooler. Whether that be by using a 12x12" stacked plate cooler or a 3x5" tube and fin. I have no idea what the calculations are exactly, I can do rough numbers, but thats it.

Someone could theoretically run a cooler only and have hotter temps. an *extreme* example would be someone who is running a tiny tiny 3"x3" tube and fin cooler. (I did say extreme, and unprobable, but it does get the point across).

Also, I think there is very wide varieties of where the temp sensor is placed. In pan, pre cooler, after cooler, etc etc.

Everyone's experience is unique and useful when trying to read these threads. I know that when I did my lift... even though most said it wouldnt be an issue... some mentioned issues that could be possible... and indeed, most of it did happen. (I had bump steer, the shackle flip caused weird balencing issues from front to rear, causing even more bump steer-; then I had issues with driveshaft vibes- shimming didnt help- so i got a CV shaft, but it was a little too long- so then i added a 1" spacer/relocator). Thats after i tried shimming the t-case, dropping the t-case, etc. etc. Each individual mileage may vary.

 

[ryoken]

Thanks Patrick....

Props for the informative post, i didn't mean to belittle its importance or anything... Well written....

And Scott, my apologies if my posts came across as implying ignorance on your part.. That wasn't my intention.. I've read many an informative post from you, I just don't agree with you on this particular issue...

take some solice in the fact that I wholeheartally agree in the winter aspect. Enough to where I've changed my mind about going back thru the rad in the last 3 months or so.. extra $100 for the rad, some more AN fittings and hose, but worth it imo, to get that needle moving a little quicker in the winter...

 

[4X4HIGH]

And Scott, my apologies if my posts came across as implying ignorance on your part.. That wasn't my intention.. I've read many an informative post from you, I just don't agree with you on this particular issue...

Apology accepted.

Like pookster said, everyones set-up is different and could make a difference.

I think that sometimes posts like these end up making for better knowledge as it will tend to make someone with more knowledge respond whereas they might not have at first reading.

 

[ryoken]

I think that sometimes posts like these end up making for better knowledge as it will tend to make someone with more knowledge respond whereas they might not have at first reading.

I've been in some very combative forums over the years, and sometimes those debate tendencies spill over in here.... I hate turning threads into abortions, but sometimes the stubborn side of me wins...

Actually all this tranny cooler talk got me thinking about my system and how I really should go look up what the specs on my freebie cooler are... Hmmm, 26,000 GVW....

I've been planning my oil cooler side for awhile now... When the factory hoses start looking like they need a replace, I'll go with some Proflex and Endura lines, and I've been eyeing the Fluidyne and Earl's coolers... Look nice..

Anyone have any companies they like what they're doing? Earls, B&M, Perma-Cool, Howe?

This stuff from Howe looks interesting... http://www.howeracing.com/Radiators/Index-Coolers-CoolTube.htm

 

[DPI]

This may not be whats going on but I just had a experience that drove me crazy.

My sender is in the pan and after about 20 minutes of the truck just idiling the temp got up to 250 So I pulled cooler lines making sure I was getting fluid flow, which I was. So then I turned my attention to the guage/sender.

Replaced the sender and it still happened. So I started messing with the guage and it turns out the ground in the guage was loose. Tightened it up and she nevers gets over 150


If it really is getting to 300 , then you would have fluid SHOOTING out of the vent tube, so I think you should first make sure its actually getting to 300.

Sorry for causing such a big issue. I didn't expect it to go this far...



I think we have a winner with the above statement...


I pulled my guage and checked the connections. I reinstalled the guage and started touching the wires and studs on the back of the guage. When I did, the guage moved around. This started to concern me. I then pulled the wire that is tied into the dimmer switch. When I did, it pegged the guage.

I then installed the wire and turned the dimmer switch. Doing this changed the temp guage. I found that there were some wires shorting out near the fuse box. I fixed the short and ran it all day saturday with no heat issues at all. Actually the trail temperature didn't get over 160 in the pressure port or the return line...

Thanks for everyone's help on this.

 

[Pookster]

I blame the mfgs for badly stating their coolers. I mean, WTF does a 26000 GVW really mean? It doesnt mean 26000 lbs of gross vehicle weight. heck, permacool says that compact cars get 12000 lb coolers. the GVW of compact cars does not come near that. a 30000 gvw cooler is " Recommended for 28 foot to 46 foot motor homes with frequent heavy towing."

thats kinda bogus if you ask me. In other words, just get the biggest baddest cooler you can, and call it a day. The risk of having some moisture in the fluid vs having the fluid over heat... I'll take the moisture.

 

[K5er4Life]

I blame the mfgs for badly stating their coolers. I mean, WTF does a 26000 GVW really mean? It doesnt mean 26000 lbs of gross vehicle weight. heck, permacool says that compact cars get 12000 lb coolers. the GVW of compact cars does not come near that. a 30000 gvw cooler is " Recommended for 28 foot to 46 foot motor homes with frequent heavy towing."

thats kinda bogus if you ask me. In other words, just get the biggest baddest cooler you can, and call it a day. The risk of having some moisture in the fluid vs having the fluid over heat... I'll take the moisture.

I agree, I ran the biggest cooler I could in my blazer. Heres my plan, and I will post my results once I get my temp gauges.
In my crew cab it has a aux cooler that is ran in conjunction with the radiator cooler. This one has a th400, 3.73's with 37's. Its a 4x4 crew cab with a 4 inch lift. The 400 has a stage 2 B&M shift kit.

The blazer has 38's and 5.13's, and I have a cooler only setup. And has a full manual valve body.

Both trucks have the big B&M cooler, 30K or something like that. And also have the B&M deep finned aluminum pan. Neither of these trucks have temp gauges, yet. I am going to buy trans temp gauges for both trucks. Anyone have any gauges in particual that they like or would reccommend? I want to do this real soon, especially on my crew cab because its not geared yet. And when I do like I said I will post results of my temps and what they run. The crew cab is my daily/ tow rig, althoug I am not going to tow until I get it geared the truck does see some pretty good hills on a regular basis when I go out riding.

I will say however, my blazer with the cooler only setup, has a fresh th400 and Im not easy on that trans. Nevertheless, the fluid in the trans (which has only been in there for 5 months now) still smells like brand new valvoline dexron. And for 3.5 months out of the 5, I ran it with 3.73's.

Dont know if anyone will be interested but that might help give a little insight as to what each trans is doing with or without the lines being ran through the cooler, I will also post ambient air temps and driving conditions.