CK5
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Considering a re-gear...

Paul you got a 700R4 right? If so don't waste you time with 4.10's and 35's. You will hate it. Get 4.88's. My 700R4 with 35's is marginal with a 350.

Harley
 
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Swap your axles for 3/4 ton units and you'll get 4.10 gears...

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you won't always get 4.10 gears, most likely in the 73-80 or so you will. my 3/4 ton has 3.42 and im buying a 86 k20 that has 3.73. im just saying just because its 3/4 ton doesn't mean its 4.10 gears, check it first /forums/images/graemlins/waytogo.gif

[/ QUOTE ] My 78 3/4 ton axles are 3.73's.

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I got ripped! Mine came with 4.56 /forums/images/graemlins/angryfire.gif
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[/ QUOTE ] Sence you feel you got ripprd, I'll be a nice guy and swap my 3/4 ton axles for yours aslong as they're 3/4 or even 1 ton axles. Bring them on out to Western South Dakota. I'll even turn some wrenchs with ya. /forums/images/graemlins/deal.gif
 
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Please don't encourage the children when they misbehave. Report it to a moderator rather than adding fuel to the fire.
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700R4 with 33's = 4:56 gears minimum!!!
Overdrive is nice sometimes...
 
Harley , my decision is based on driving my truck right now. I mean I have a 3.06 to 1 first and a torque converter , it is workable now. 35's will measure 34 if I am extremely lucky . I will feel the difference for sure going from 3.08's . If my truck didn't climb over everything I have tried thus far , and didn't cruise 65 mph, I may go higher than 4.10's /forums/images/graemlins/k5.gif

BTW , I have decided to keep my current Blazer never going taller than 35's, and get a wrecked truck to cut up alot
 
I don't say to go to 4.88's for trail use with 35's. 4.88's will make 35's very driveable on the street.

4.10's with 35's (34") at 65 ph in OD is only 1850 RPM. That is barely above factory stall speed and also below most motors mid range power band. This will not promote 700R4 transmission life due to the fact that the transmission will have to kick back and forth between D & OD alot. Your cruise RPM at 65 should be in the neighborhood of 2000-2300 RPM where the engine makes its torque.

So far with your truck you have never felt is true highway potential. I didn't understand it either until I had my 4/56's with my 32's. I cruised at 2250rpm in OD at 65 which is about where you want it to be. I also had the ability to pass people and accelerate up Sunset Point.

I didn't have to be that guy in the right hand lane anymore doing 50mph up sunset point because someone broke my momentum and I didn't have enough gear to get my truck going again. I truely had the ability to have someone brake my momentum and then step on the gas and start to accelerate again. It was a great feeling not having to have my foot to the floorboard while climbing heavy grades. It was also nice to not have to kick out of OD to climb small hills on the highway. I can't even begin to tell you how cool it was when I climbed Sunset Point with throttle left to spare. Even when I had 32's and 3.73's I had to run sunset point with the throttle to the floor to keep momentum and stay at 65 mph. With the 4.56' it was easy.

Your transmission will love you for making sure it is stalled and locked up and not having to kick in and out of OD. You will love yourself and your truck when you don't have to be the guy everyone stares at when they pass you on the mountain grade.

Ask Jay 4.10's and 35's kinda sucks.

I will honestly tell you I was going to regear to 5.13 just so I could get back all my highway power. I was already setup to by a set of 5.13's for my front axle and I decided not to because I need the money to move. Otherwise it would have been a done deal. Once I get settled in Colorado I will get 5.13's for my truck. I am going to do it just to make street driving better. You know I have enough crawl right now. I am not regearing to get more crawl ratio. It is purely a streetability decision.

If you do alot of highway driving at 75mph on flat grades then 4.56's might be an option to consider but if you seriously only do 65-70mph on the highway and ever go the rim country then get 4.88's.

I cruised from here to Safford at 65 mph with 32's & 4.56's and got 11-12mpg doing it. That may not seem good to you but for what my truck was getting prior it was a very slight loss of mpg if any.

When I did my regear I was debating between 4.56's and 4.10's. Now that I have done it I will tell you flat out that if I would have regeared to 4.10 it would have been the biggest mistake I could have made. 4.56's is marginal.

I had 32's and 3.73's. I went to 35's and 4.56's. If you do the math it is a wash totally. I didn't gain anything, I just kept it exactly the same. The only thing that makes it half livable and half right is the TPI. Don't put yourself behind the 8 ball and waste a bunch of money.

Harley
 
yeah, if your going to be paying for these gears, definitely go to 4.56 or higher if you have the 305. I am going to 4.10 with the same setup, mostly because i don't want to break anything and they are going to be free! If they break no big deal, I will have 2 other entire axle assemblies to put together any way i want.
 
I'm runnin a TH350 with 4.10's and 37's. It flat out sucks going up anything, but I top out at 3000 RPM at 75 MPH. The tranny starts to serge around there. I do have a low stall set up though so there is no *get on it* above 50 MPH. I could go for 4.56's but that would kill my freeway speed. It is a real trade off with out overdrive.
 
I've always thought it would be cool to run a 700r4 with 5.13s and 33's. It would be a beast pulling I-70 through the mountains here. I'd go full manual and basically use 1st like a granny low and start in 2nd most of the time. Just my thoughts and ponderings.
 
OK lets say I went with 35's ( measuring 34 ) and 4.56's . My rpm in 3rd at 65 will be 2929 , dropping a little lower with a shift to OD . I would like to cruise with my engine around 2500 rpm , that why I was thinking 4.10's with 34 inch tall 35's and OD will get me there at 65 mph . Will definitely have more power than I have now .

Oh well , didn't mean to take over this guys thread .

You and harley have until tax time to talk some sense into me ...........and trim my fenders SLIGHTLY for 35's , no big big big big dog trails though , gonna buy a beater later to really cut /forums/images/graemlins/thumb.gif
 
In OD with 35's (33.5-34") and 4.56's my 65 MPH cruise is 2050 RPM. That is on the very low end of the engines power band. 2950 is cruise in D but with a 700R4 you don't cruise in D unless you are climbing hills.

If you have to cruise in D now it is because of your lack of gearing. You should be cruising in OD on the highway unless you are pulling a hill or pulling a trailer.

4.88's would get you up 2200 RPM cruise and 3150 RPM. In my honest opinion that is about right. That is just a little under what I ran with my 32's and 4.56's which I REALLY liked and wish I still had.

Harley
 
When I was in Colorado I ran Eisenhower pass in my truck. Mild 350, 4.56's, and 32's (31" true height). My truck had every tool I own in the back and was HEAVY. I had no problem pulling Eisenhower at 65 without any deceleration and still had throttle left. I was pretty pleased. I had to back out of the throttle so I would keep the RPM's down some. /forums/images/graemlins/waytogo.gif

If you have a good motor 4.88's and 33's would kick arse in the mountains. I am going to go to 5.13's and 35's when I move to Durango.

Harley

Harley
 
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In OD with 35's (33.5-34") and 4.56's my 65 MPH cruise is 2050 RPM

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If thats true , then it doesn't sound too bad after all . Was concerned about buzzing the engine real high for extended periods . I do cruise the highway in OD now , most local freeways are 65 mph and I can do that in OD ............when flat /forums/images/graemlins/k5.gif
 
Now I am really confused. I was going to run 4:56 with my th350 but now I think I might stay with 4:11 and my 35"(34.5") tires?
 
It would kind of depend how much interstate travel you do.
If you want to run 75mph, with the 35s(say 34" actual) and 4.11 you'd be runnin about 3000rpm.
Same setup with 4.56 you'd be runnin around 3300rpm.

If your TH350 is nonlockup you're going to see higher rpm's than that.

With my current setup with the TH400, nonlockup torque converter, I'm going to use 3.73 gears with 33's. I run a lot of interstate and I want to be able to at least travel 65mph at about 2800rpm. I add 300rpm to the formula results to account for nonlockup slippage, that's how I get approx 2800rpm with 33s & 3.73 gears.

No matter what, I know the 3.73s are going to be a hella lot better than the 3.08s I have now.
 
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