t-34 transmission


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Golden Jubilee
Golden Jubilee

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Post Mon Aug 18, 2014 5:48 am

t-34 transmission

I'm looking at a transmission at a junkyard that may be a t-34 . I looked at Gangster Mikes site and it looks like it should have numbers around the drain plug but I don't see them . Are there other ways to tell what it is . I'm interested in the trans if it is syncronized , there were other t series trans 5 OD that were not sync , and short of opening it up is there a way to tell them apart ?
I took an input shaft , clutch disc , and an f-51 case there and compared them , and it looks like it will bolt right in . this trans is new enough to to have an elect connection on top of the shifter cover, has a dbl.jointed e-brake handle and the same 9 1/2"size e-brake drum on the back as an f-51 , but the driveshaft to drum connection is a little different , I'm thinking that the output shaft will except the older drum if the splines and diameter is the same . Anyway it seems like a possibility for a 5 OD for our older trucks . I know that the t series was available in the Loadstars .
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Golden Jubilee
Golden Jubilee

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Post Mon Aug 18, 2014 9:05 am

Re: t-34 transmission

I read somewhere, probably here back a few years that the shift pattern for a 5th over is over and up towards firewall and 5th direct tranny is over and back towards the seat. I never had a chance to confirm this but possibly others that know for sure will chime in. MM
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Golden Jubilee
Golden Jubilee

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Location: SW Washington

Post Mon Aug 18, 2014 10:31 pm

Re: t-34 transmission

Every OD tranny I've driven has OD forward. Somewhere I ran across some info that said the T-34,35,36 have synchros and (I think) T-31,32,33 are the same trannies just non-synchronized.
'52 L-160 dump truck
'57 RD-405
'58 Allis Chalmers D grader
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Golden Jubilee
Golden Jubilee

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Joined: Tue Dec 04, 2012 5:38 pm

Post Tue Aug 19, 2014 6:40 am

Re: t-34 transmission

I turned the brake around and counted the revolutions of the input shaft with the shifter forward and back and it was 1 turn for 1 turn while the shifter was back and 3/4 or so on the input for a full turn on the brake when the shifter was forward so for sure its an OD trans . I was hoping to find some way of telling if it was a t-34 ,which I think is the only 5 OD that had syncronizers by numbers from the outside . Scottso are you out there ,? , I was going to PM you to ask but thought it would make a good post because it leaves another option for a 5 OD that at least I was unaware of when I was looking .
My truck a KBS6 had the older 4 speed that came behind the bld 250 that came in it , it was mounted with the 4 speed bell housing to the BD 308 that was in my truck when I got it . I changed it to the f 51 , a 5 OD that required a different bell housing but bolted up just fine no modifications nessessary , other than shortening the drive shaft . Now it looks like I could have a trans with syncronizers that would bolt right up , which means if you take it a little further that if you had a KB 6 with a 4 speed and wanted a 5 OD with syncronizers you could find a loadstar and identfy by numbers a t 34 trans , find a 5 speed bell housing and bolt it right up . In that case you would have to shorten the drive shaft a bit .The thing is that the f-51 trans is getting harder to find and to have another option would be great .
The thing is I don't know what truck this came out of . What I need to do is identify the input shaft by part number in this particular trans and see if it is the one that was in the t-34 option for the loadstars , and also check the output shaft and make sure it is what I think it is and it fits my brake .
I'll keep working on it and keep you all posted .
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Golden Jubilee
Golden Jubilee

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Post Tue Aug 19, 2014 7:44 pm

Re: t-34 transmission

Where to start? Image

I spent a few hours with my nose in the books (5-6) to find out what the differences are in the IH 5spd's,ie; the T-34,35,36,495,496,698 & 699. They all "look alike" and share a majority of internal parts. They are "constant mesh" and are synchronized in 2-3,4-5 direct in 5th transmissions (except the T-34).
The shift pattern is the same in all but the T-34...
Left up = 1st
Left down = Rev.
Center up = 2nd
Right up = 4th
Right down = 5th
1 2 4
R 3 5
With the T-34 4th & 5th is opposite the above.

Here's some ratio's,1st,2nd etc.
T34 6.21, 3.43, 1.81, 1.00, .082
T35 Direct in 5th = 7.17,3.96,2.36,1.41,1.00
T36 Direct in 5th 1.22 in 4th = 6.21,3.43,2.05,1.22,1.00
T495 Direct in 5th = Same as T-35
T496 Direct in 5th 1.22 in 4th = Same as T-36
T698 Direct in 5th = Same as T-35
T699 Direct in 5th 1.22 in 4th = Same as T-36

If there's no tag then try the case casting pn,if the 1st 3 digits are 238 it's a 34-36,if they're 440 it's a 495/496 and 497 for the 698/699.

Another thing I found is that a T-34 from a Loadstar/Cargostar will have a 1-1/2"-10 spline input shaft no matter the engine and if from a light line truck will have the more common 1-1/4"-10 spline as will a 35/36 unless it was mated to a diesel or RD engine,which are also 1-1/2-10.
That being the case,a T-34 from a Loadstar would be easy to ID.

The gearing difference between them is the main drive gear (aka. input shaft) and the gears on the countershaft,I made a list up if anyone's interested. I also have a tooth count if I deciphered the aftermarket catalog I have crappy listing correctly(?)

OK,I'm tired,did I miss anything?
12 yrs.exp. in IH dealer parts dept.
Never argue with a fool...
If you don't have anything nice to say...say nothing.
If you don't learn something new everyday...you weren't paying attention.
THINK! Be sure brain is connected before mouth is in gear.
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Golden Jubilee
Golden Jubilee

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Joined: Sat Oct 26, 2013 10:11 am

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Post Tue Aug 19, 2014 10:32 pm

Re: t-34 transmission

That's some good info right there! The part about input splines could make things a lot easier for a guy.
'52 L-160 dump truck
'57 RD-405
'58 Allis Chalmers D grader
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Golden Jubilee
Golden Jubilee

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Joined: Tue Dec 04, 2012 5:38 pm

Post Wed Aug 20, 2014 6:06 am

Re: t-34 transmission

You are an amazing resource Scottso , thats a lot of work .Thank you those casting numbers should confirm it , I guess it was from a lighter line truck . I was thinking about the parking brake and that it might be from an r, or s because it's a drum like mine , the loadstars look like they had an option for similar brake but also had one that has internal shoes ,a little newer . I talked to Irish Mike and he said that the t-34's were sought out and put in a lot of different trucks for the benefit of overdrive and were mated to many different makes with the rounder type bellhousing .
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Golden Jubilee
Golden Jubilee

Posts: 743

Joined: Tue Dec 04, 2012 5:38 pm

Post Sun Aug 31, 2014 6:30 am

Re: t-34 transmission

Well it turned out not to be an OD trans but it was syncronized I had counted revolutions in what I thought was the 4th position and it was 1to 1 and the 5th position I had reversed the counts from front to back , a bad case of wishful thinking . Never determined which trans it was by numbers ,but it would bolt right up all the dimensions work and the yoke from the driveshaft would bolt right up . From all this I am pretty sure that a t-34 with a 1 1/4" input shaft would bolt right up , if it could be found . I wonder what light line trucks came with them , I'll have to do some looking in gangster Mikes library .
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Golden Jubilee
Golden Jubilee

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Joined: Fri Nov 30, 2012 6:22 pm

Location: Grand Junction, Colorado

Post Sun Aug 31, 2014 8:53 am

Re: t-34 transmission

I pulled a Transmission in a junk yard many years ago only to find I too had pulled the wrong one. MM
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Golden Jubilee
Golden Jubilee

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Joined: Thu Jan 24, 2013 8:49 pm

Post Mon Sep 01, 2014 5:41 pm

Re: t-34 transmission

The T-34,36 were optional in light trucks from at least '65 up to '73(?) and Loadstars/Cargostars of the same years along with the more common T-35.

Here's some food for thought,a quote by Doc Stewart on BP...

"A. The T34 has a large jump from 3 to 4. No problem in flat country but a pain in the hills with a load on. No problem with an empty truck.
B. An OD transmission is an advantage only when it puts the engine in a better operating range. For example, if you are running 3.07 gears behind a 266 SV8, the OD is not going to do much and you will be constantly shifting to 4th whenever there is any need for torque. On the other hand, if you are commuting in flat country in a truck running 4.88 gears and street tires, the OD will be very useful.

I had a T34 in an 8000 lb service truck running 4.30 gears and normal tires. Towing with that trans in the hills was a pain because when you lugged down far enough to shift down from 4th to 3rd, the was a 2000 RPM jump which resulted in actually slowing down to shift down. I changed to a T36 and am much happier towing loads in hilly country. On the freeway with no tow, the T34 trans was OK."

With your 308 the above could be worse,he has an SV8.

You should see if you can ID that trans,even a T-35/36 would be better than a 4spd. or old non synchronized 5spd. Plus if you really want a T-34 a 35/36 can be made into one if you can find the needed gears.
12 yrs.exp. in IH dealer parts dept.
Never argue with a fool...
If you don't have anything nice to say...say nothing.
If you don't learn something new everyday...you weren't paying attention.
THINK! Be sure brain is connected before mouth is in gear.
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