The Stovebolt Site Forums The Shop Area Driveline Transmission advice needed

The three speed tranny on my 54 1/2 ton went out and I need some advice on my options. Mainly cost and ease of installation of 4 speed vs. automatic. I want to change the gear ratio to help it cruse at highway speed. I have found a trans. shop that will do the work but I don't know what year/make of transmission would work best and be most cost effective in four speed and auto. What do you recommend as good fits for my baby?

you might post this in the transmission forum

Cheapest easiest way is likely to rebuild the 3 speed and get the 3.55 gear set for your rearend.

Other options include changing the rear and using a wide range of other transmissions.

Some transmissions that have been used include, but are not limited to the following.

T5 5 speed. (search the tech tips)
A833 4 speed
t10 4 speed
saginaw 4 speed
sm420 4 speed
sm465 4 speed
3 speed with OD
NV4500 5 speed

As for automatics
th350
th400
700r4
200r4
powerglide
dual-range hydra-matic

What engine do you have in your 54? Do you plan on swapping engines?

The Manual transmissions are going to be a much simpler swap than the automatic transmissions.

You could do a T5 swap. 5th gear is overdrive. Look for the tech tip and read about it. Many guys have done the swap and speak highly about it. If you go to local car shows and ask around you should be able to find someone to do the swap for you.

What rear end do you plan to use?

Any transmission change for higher speed driving will require a different rear end.

An overdrive transmission will work well with a stock rear end.

I'm replacing my 3 speed tranny soon because I want syncro in first gear. I found a good 3 speed with syncro out of a '65 Impala. Something to think about!

Another question to ask yourself is "do I want to cut up my truck to install the transmission?" There is only one automatic transmission that fits. The one that chevrolet used at the time and the rear crossmember is special just for that transmisson.

The important issue here is what engine do you have? A 216,235,261 engine has no provision to mount a late model transmission. This leaves you with a small choice of automatic transmissions to use. If useing a standard trans. you have a number of choices. The t5 seems to be the prefered trans.that most people switch to, 4 gears plus overdrive. The other issue you will need to deal with is your rearend,is it open( has a drive shaft that you can remove) or closed ( with a torque tube). If it is open you can put just about anything in, however with the closed drivshaft you are pretty much limited to what you already have.

His truck should have an open rear end? He mentions its a '54.

What overdrive transmission will work with a stock 1954 1/2 ton enclosed driveshaft rear end?

The only torque-tube overdrive unit (not a transmission) that I have seen requires that the torque-tube and enclosed driveshaft be cut (a Truckstell overdrive).

1st series 55 was the first open driveline. Your 54 should still have the closed driveline unless someone changed it.
Fred

I have the 235 and as it seems to be running well and compression is good I'm happy with keeping it as I think with better gearing it will cruse as highway speeds just fine. Many transmission shops are leary of taking on this project due closed driveline and getting into possible rear end, speedo, and other issues.

I think 54's were all closed drivelines. Thanks for the great advice guys, I'm leaning toward rebuilding the three speed and putting in the 3.55 gear. I suspect my truck has the heavy duty 3 speed but how would I tell for sure? Also I'd need to replace the gear shift lever,(mine rusted and broke off and is braced with a metal splint and duct tape) which may mean replacing the upper control shaft - parts I have not found in any of the catalogs. How tough of a get is this?

I should also add that I love the foot starter. Would any tranny / clutch changes mean a change in starters?

If whatever transmission you use can work with the original clutch housing and any 216/235/261 flywheel, you should be able to use a 6v or 12v foot-actuated starter.