VCCA Home Forums GENERAL DISCUSSION New User Forum Transmission problem, 1941 Chev pickup

Noise in 3 speed transmission, apppears to be damaged bearing on input shaft. I have good 590874 and also 1948 side cover trans. Will internal parts of either of these fit the 1941 591195?
Are the needle bearings on the inner end of the clutch shaft a known weak spot?
Thanks!!

YES! I have had them melt and weld themselves to the male shaft end. They are in use anytime the input shaft is turning except in high gear. I suspect most of the damage is from a low level of gear oil and when the car or truck is left idleing. or pulling a load in R,L or 2nd.
my 51 and 52 cars had 14 needles . The design of the 54 and maybe the 53 had 24 needles:
I have found them asking for the roller needled for a 1972 4x4 fourspeed truck.
As far as I know they are one size fit all (4.352) 1/8" x 1/2"

1939-48 Passanger







1949 - 1954 passanger

The 590874 is a 1937-1939 rans. and no gears will interchange.

The 1948 side cover trans. is probably from a passenger car.

Your 1941 1/2 ton trans had "heavy duty" carbirized gears and are different from the passenger car gears.. See shop manual about the gears and how to identify them.

The 14 roller were used for many years and the rollers are still available. In 1953 a second set of rollers was added to provide better alignment between the two shafts to eleminate the jumping out of high gear problem.

As long as there was at least 1/2 pint of gear oil in the transmission 99 9/10 percent of the rollers lasted the life of the car.

I have owned this 41 Chev pickup in excess of 40 years and managed to keep it roadworthy most of the time. I have had the 580874 transmission laying around most of that time "just in case", so I can get rid of it now. The side cover box is identified GM591615 on the housing and 3688832 on the cover. I am very pleased to know the rollers can still be found. Thanks for the help!

Thanks for the help. I'm guessing I'll be needing the needles, and am pleased to know they may be found.

Chevgene,

You mentioned that 14 rollers was standard, but in 1953 they added a second set of rollers to give better alignment and to eliminate the jumping out of high gear problem.

How prevalent was the jumping out of gear problem in the 40 and up transmissions? On a road trip last summer, I had my 40 1/2 ton 3-speed pop out of high gear, twice while drifting down hill and once while pulling up a long hill. I've since inspected the internals and everything looks to be in good shape. The pilot boss on the main shaft is in good condition, as is the pilot bushing in the back of the crankshaft. I'm going to pull the transmission and have another look at it, and this time, I'll check the alignment of the bellhousing bore with the crankshaft. Beyond that, I guess it may be a design problem that I have to live with.

Mark Yeamans
VCCA #35724

When the 1937-1948 transmission were new, or lets say in their day, jumping out of high gear was unheard of. If it did occur on the cars with the vacuum assist it was due to the adjustment of the assist mechanism.
When there is something worn insde the transmission they can jump out. There could be a long list of things. Also the alignment between the transmission and bell housing can cause a problem. First the contacting surfaces must be clean and free of paint, etc. Shimming can also eleminate the problem.
The problem became more common in 1949. More or less uncommon from 1950-1951 and came back and was more common in 1952. At that time Chevrolet's fix was to install the main drive gear and main shaft from a 1953 which had the double set of rollers.
Just the normal wear on the area of the shaft that the bearngs ride on + the wear of the bearings could contribute to the problem.