The Stovebolt Site Forums The Shop Area Engine Shop 1952 Chevy 3/4 Rear End Question...

Hey all...

I'm sure this has been covered before (I tried searching but didn't find what I was looking for or anything that specifically applied to what I was asking about). As the title says, I've got a 1952 Chevy 3/4 ton truck. I bought it when I was 15 (and am now 23) with a 292 and a two speed powerglide with the stock rear end. I can run about 55ish (the speedo reads about 75, and I've GPS'd it to about 55) with the motor wound up which was fine when I was in High school simply because I didn't care and I looked cool riding around in a 52 Chevy truck...lol...I have done alot of body work, interior and paint work to the truck, so it looks nice enough, not going to win any shows or anything, just looks good enough for me. Enough background stuff...

The real question is this: I would like to change out the gears in the rear end without changing the whole rear axle. I don't have the fabrication skills or knowledge to do so. Is there anybody out there that makes new rear end gears for a 3/4 ton truck? I've looked and can't seem to find anything. I"m just looking to be able to cruise to neighboring towns without getting flipped off on the way for going too slow on the highway. Oh I should also add, that I've redone the entire brake system (still drums) so stopping is not an issue. Thanks for your help in advance.

Reid

Forgot to add, that I am already running a taller tire (16")

Nope, there are really no readily available choices on faster rear axle gears for your truck.

Chances are you have the stock 4.57:1 R&P.

If you search you can find some 4.11 gears from a slightly later model axle, someone will be along with the details shortly.

Then theoretically there are some 3.90 or so gears out there to fit your axle, but I have talked to many people who have been actively searching for these elusive gears, and not one of them have found any.

The simple solution is probably an OD transmission and or a later model rear axle.

This site will be a big help with figuring gears and speed: http://www.onlineconversion.com/bigger_tires.htm

Grigg

The '67-'72 was available with the 4.11 gears, and the 3rd memeber is a direct swap into your existing housing. One thing I'd suggest would be to change out the 'Glide, perhaps to a 700R4. That will not only get you better gear range (4 instead of just 2), but you'll gain an overdrive gear which will greatly help in the rpm dept. Combine that with the 4.11 gears, and maybe a taller tire, and you'll have a truck that'll cruise vry nicely w/o overrevving the engine.

The 4.57 gears were typical but 5.14 were an option in the 3/4-ton. You might want to confirm which you have because going with the 4.11 gears would be a big improvement over the 5.14s.

If you are running a 292 with a Powerglide another choice is worth looking at. The 700r4 or 4l60 overdrive automatics would bolt right up to the 292 and give you about 30% overdrive giving you 1.3 times 55 or about 72 as a cruising speed.

That 292 and Powerglide are not original in that truck. Are you sure that is what it has?

OldSub...

Thank you for your reply...I did not say that it had the stock motor and transmission...only stock rear end. I know the motor is a 292 and I know the transmission is a Powerglide since I know the person that did the swap.

About this 700r4 or 4l60 option...I guess I'm not very familiar with those, but they should bolt up to the 292? If that is true, would I still need to change the rear end gears?

As for the gearing, are there any particular model '67-'73 vehilces I should be looking for, as in trucks (1/2, 3/4, ton) 4x4 car?

Thank you all for your help so far.

You'll want to look for a '67-'72 3/4 ton Chevy, V8 automatic. You'll want to look for the one with the drop out center section, GMCs and most Camper Specials use a different rearend (Spicer) that won't work.
As to the TH700R4 and 4L60E, both will bolt up to the 292 just fine, they are very similar to the TH350, I would advise the 700R4 over the 4L60E only because of the computor controls required to rune the latter. Those trannies are essentially the same otherwise. Yuo might be able to get away with just the overdrive trans swap, but doing both will give the best overall benifit, especially for a daily driver.

I would find some in your area A BOLTER? to help me change the rear end to a late model that will be cheaper. the rear end is the problem. you can always put a 1/2 front axle in the future so the expense is done in two payments. you will love a 3.27 gear ratio or so.

If you want to keep it as close to org as you can look for 60,s 3/4 ton that had an auto as it should be geared higher.If can,t find bite the bullet and install a pass diff as it should be no problem unless you are hauling heavy loads...doc

Reid sometimes newcomers here don't really know what they have, so asking to confirm seems a good idea when in doubt.

There is more than one version of the 700r4 available, but the one designed for Chevy V-8s and 4.3 V-6s should bolt right up behind the 292.

I believe the transmission will be a little longer than the Powerglide and use a different yoke and might require modification to the transmission crossmember. I'm the wrong one to offer some of these details, but these are all things you'll want to check so you are prepared when you start the project.

I'd make the changes one at a time, the transmission and rear gears, because you might find with one or the other complete you may be satisfied and not need the other.

A few month back I had posted a similar question. The rear end swap is one option...a 67-72 with a 4:11 pinaple. But the tranny swap to a 700R4??? Wanting to keep a mannual tranny, what is another option? Also Steve has a good recomendation of swiching one piece at a time. I have a 4:57 rear in my 3/4 ton and will try the tranny swap first to see how it does? Engine is a 261.
Anybody done a newer tranny with original 4:56 rear?

Eric

Eric,

This is a frequent topic in this forum. Look at this post from "Mugsy" in this thread and you'll get an opinion about leaving the rear end as is (4.57) and changing the tranny to a T5 which has an OD.

https://www.stovebolt.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/59155/fpart/2

The passenger diff will not swap into the existing housing, and would require changing the whole assembly. That would also require 5 lug wheels, and reduced braking capacity (smaller brakes). If you were to swap the entire rear, one from an '80s/90s model van (Dodge/ford w/Dana 60) will fit nicely. I'm not sure about the GM vans, should be similar exept for the use of the Corp. 14 bolt in either semi or full float, depending on GVW.

Thanks for your help Longbox.

If I were to go after a '80s/90s van. What model would I want? I've been to several different salvage yard and every E250 full float axle that I find measures the correct backing plate distance (when I say correct I am refering to what is currently in the truck), but the wheel mounting surface is about 4-5inches too wide. Any suggestions?

Thank you all for your help so far.