The Stovebolt Site Forums The Shop Area Driveline Chevy Torque tubes 47 to 50s

Did Chevy make different size torque tubes in the trucks back then? I have a 49 3100 per the numbers but the torque tube rear pinion whole seems a bit to small for the new 49 bearing. The engine in the truck is not original so maybe the complete drive line was upgrade by PO with something different than a Standard 49. Any help is greatly appreciated.

Chevy cars of that era also had torque tubes of different lengths from trucks. Not sure of specific differences beyond that, but experts will be here to answer your questions shortly...

If you mean this Pinion Counterbore
The pinion bearings were the same from 1937-1954 therefore the Pinion Bore is the same size from 1937-1954.
Group # 5.447 Front bearing part # 954780 double row
Group # 5.484 Rear bearing part # 125630 single row This one has a little bigger diameter.
However there were some improvements made in the early 1950's on the front bearing Close style cage vs. Open style cage

The truck axle is made of a heavier construction than the passenger car axle.
Read Here Under
>Rear Axle Assembly, 1/2 ton and 3/4 ton trucks
>Pinion Assembly---1/2 Ton Model
>Axle Shafts

Torque tube diameters changed a few times from 1929 and up. I would think that the 1937-54 would all be the same as they all use the same ball and the front skinny part of the torque tube were all 2". The rear half was increased in size from 2 13/16" in 1950 to 3 1/4" in 1951. This was done to "raise the fundamental frequency of torque tube vibration. With this change, vibrations from other sources no longer combine with that of the torque tube, over a narrow speed range, to produce a peak vibration point which was encountered occasionally in the past".

1/2 ton Rear axle cross section
Toque tube rear axle exploded
GM 1/2 ton axle overhaul Film strip slides

1/2 ton truck axle uses a Oil Retainer passenger car doesn't.
The purpose of the pinion bearing oil retainer is to slow the flow of gear lube into to the axle housing,
which helps to maintain a bath of gear lube on the front pinion (thrust) bearing.

Maybe they sent you the wrong bearings.
Why are you installing new bearings?

This is great information Jorb;

I bought a 49 Chevy 3100, however, discovering it may be something else or a hybrid. Had a replaced engine with block of 51 and head of 52 and had helper springs. So maybe the PO changed the complete drive line.

I purchased the complete 1949 kit to upgrade the Ring and Pinion gears to 3:55 from Patrick. The front bearing that was sent to me in kit is too big and they sent a second which is same. Too big. Is it possible the torque tube is of a different size and if so I would like to buy the correct bearing to complete the upgrade.

Thanks

Pat

It is very hard to say what has been done to your truck, I would like to see the parts.
The same front pinion bearing was used from 1940-54 in trucks.
Depending what was done, you may have spline count issues also, even at the U'joint end of the drive shaft.
You may be better off finding a 1948-54 torque tube assembly.

1929-57 Master parts catalog
Group # 5.504 Carrier Assembly, Differential, w / Propeller Shaft Tube (torque tube)
It shows cast numbers, tube length and parts numbers for torque tubes from 1937-1955.
There must be typo because 55 1st series 1/2 ton didn't have a torque tube. Should read 48-54
For comparison 1929-54 Master parts catalog Group 5.504

Just a FYI,
To use the 3.55 ring & pinion gear set in a 54 1/2 ton truck carrier/torque tube.
You have to use a 1940-1953 1/2 ton trucks spool/differential case Group # 5.510 Part # 3652336
The 3.55 ring gear will bolt on to the 1954 differential/spool case,
but the 3.55 ring & pinion gears are larger. Because of the larger gear size,
there is not enough room for adjustment using the 1954 differential/spool case.
The 1954 differential/spool case was designed for the smaller size 3.90 ring & pinion gears.
So you are better off using a 1940-1953 1/2 ton carrier/torque tube, there is no clearance issues when adjusting ring and pinion.

1925-54 PROPELLER SHAFT HOUSING WITH DIFFERENTIAL CARRIER Passenger car & 1/2 ton truck
PART #, LENGTH, Carrier stamp

Check attached photo on How to measure Torque tube.

I agree with Pre '68 Dave it would help to see what the parts look like.
Are you sure the cast numbers on the torque tube cast housing are from a 49 3100?

Also when the Torque tube diameters changed from 2 13/16" in 1950 to 3 1/4" in 1951.
They started using a thinner-wall torque tube.

xfiles

I think you can see the pictures of my bearing hole and the bearing trying to fit. Is this bearing suppose to be pressure fit into the hole. I thought it needed to be tested and pulled in and out to get lash correct. I feel if I pressure it in I'll never get it out.

https://www.flickr.com/groups/3473408@N23/pool/

The bearing hole and bearing link does not seem to be working, it does but there isn't any pictures.
https://www.flickr.com/groups/3473408@N23/pool/

Q. Is this bearing suppose to be pressure fit into the hole?
NO,
Read
Pinion Shaft Rear Bearing Installation Spacer page 1 (lower right corner of page)
Pinion Shaft Rear Bearing Installation Spacer page 2
The bearings are light drive fit into the differential carrier or carrier bearing bore.
Adjusting Ring Gear and Pinion page 1
page 2

Rear Axle Serial Number Locations

Note: Passenger car and truck torque tube overhaul procedures are virtually the same.

The Rear Axle Serial Number code on the one I am working on is clearly GE 2 09. This is not mentioned in the documentation you provided which is very helpful. I am getting closer to a solution I think.

Here is the pictures of the Bearing hole and bearing as well as the axle cast number.

https://www.flickr.com/gp/152898395@N07/212478

For some reason I thought you were talking about the front bearing.
The one you have pictured is the rear bearing.
The rear bearing should fit 1934-54.
The bearing number should be 1506.
Does that bearing you have fit in the pinion shaft?

Looking at the Rear Pinion Bearing and hole photos .
The bearing you show in one of the photos should tap in fairly easy.
That is a neat photo because you can see what I believe is the oil seal way down at the other end of the torque tube.

Your last post showing cast number GE 2 09 is from a 1949 1/2 ton truck. 1949 rear axle pre-fix or cast numbers
It says GE Detroit regular
G = 1949
E = 3100 regular rear axle
2 = 2nd month = February
09 = 9th day = 9th day in the month.
February 2nd, 1949 > Date of Assembly in Detroit

All I can think of is:
Its the wrong brearings
There is another carrier from a different year that uses the same cast code.

You can try to give this guy a call,
Northwest Transmission Parts, Ask for John 800-327-1955
http://nwtparts.com/ He knows a lot about the parts on these old trucks.

Keep me posted on what he says.

The Bearing fits perfect on to the Pinion. The problem is the bearing seems a bit to big for the hole. I bought the bearing from Patrick's and he sent me a second Bearing and it still seems too snug. Would I be remiss to hone the hole? I will also call nwparts to see if I can buy one from him and see if that one fits.

Did you inspect the area CLOSELY for any burrs nicks or other marks that could be the issue? You would be very surprised how a small knick can make a bearing fit impossible.

Yes, that was the first thing I thought was causing the problem. Is it possible its out of round? Maybe I need to heat it up and put the bearing in ice. My concern is adjustments. This bearing might have to be removed and replaced several times for lash adjustment.

The front bearing is a loose fit, held in place by the three set screws.
The rear bearing should be a light press fit.

Whats a lite press fit? And how easy does it come pout once pressed? Anyone have experience with these bearings during lash adjustment?

Snug but not so snug that you need a pulling tool to get it out.
Place piece of wood(2x4) on the front of the propeller shaft. With a 2 pound hammer a two or three good wallops should drive it out.
If you hit it any harder you might damage the bearing or the snap/lock ring.
When you took it apart how tight was the rear bearing that was in there?

Pretty sure it took some work to get it out because I ruined it taking it out. It didn't dawn on me to note how difficult ripping it down would be nor keeping it for reference.

I cannot get the bearing to sit in the hole as described in the rebuild. I would have to pound the point of the pinion bearing with something to sit it.