VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Standard Transmission Problems

Just installed engine and transmission in my '52. Engine rebuilt, transmission came with engine, but didn't really have any info about its condition, assumed it was OK. Big mistake! First test drive everything was great until I worked up to highway speed, 50 mph, and trans jumped out of high gear and repeated this at speeds above 50mph. I started collecting parts to go trough trans and continued to drive below freeway speeds with no problems. I put about 200 miles on this drivetrain without any problem. at this point I noticed a "rubbing" sound, like something slightly dragging on a wheel. Up on jackstands to start the prosess of elimination. Determined that the noise was coming from the trans area. Eliminated clutch/throwout bearing as the culprit. Disconected u-joint and with no load on the trans, the noise went away, however, when I disconnected the "ball" housing, a large amount of oil came out. When running in gear with u-joint disconnected, oil is coming out of the trans past the rear bearing. Drained the trans and found that it only had perhaps 1/3 to 1/2 of the original fill. Oil is very "black" and I suspect has fine metal filings in it.

I realize the trans has to come out and gone through, I'm wondering if there is anything in particular I need to be aware of or look for. I'm under the impression that the '53 input shaft and mainshaft were redisigned to eliminate the earlier problems and will interchange as a unit. Since the parts manual doesn't show any seals, I assume that there are sealed bearing front and rear, obviously not sealing in my case.

Since this isn't a fun job, I only want to do it once! Any info or advice would be appreciated.

In addition to any other changes you make, the most important one is to change the input and output bearings with sealed bearings. You can remove the seal on the side that faces the center of the transmission.

Before you are finished you need to take a look at the level of lubrication in the rear end. Probably overfull and ready to be forced into the axle bearing and then the brake linings.

In addition to the information Ray posted:

When you take out the Clutch shaft (front Half) and the main shaft (rear half)to replace the old bearings with new sealed ones, notice the number of needle bearings that are inside where the shafts join. A single row of 14 is usual for 51 thru 53 transmissions. If some one has replaced the innerds with 54 stuff there will be two rows of needle bearings. It is possible to have a 1952 model year case with the improved 1954 innards. I have taken a couple apart that had the needle bearings welded by heat and lack of lubrication. The joint allows the two shafts to run at different RPMs when you are in any gear than 3rd which is 1:1 ratio and the front and rear shafts turn at the same speed. loss or worn needle bearings can cause noisy and jumpin out of gear, which can also be because of wear on the lever detents and worn shifting forks inside the transmission, as well as mis adjusted and worn shifting linkage from the transmission up and including the gear shift lever. You will observe them when you pull the side plate with the shifting levers.

You might want to research the archives under "Transmission woes" I posted a problem about jumping out of gear. Lots of good responses there. Also you will have oild coming from the transmission to the un joint as that it how it is lubricated, Probably want to order and Oakie bushing to replace the bushing in the front of the drive shaft and the seal located right behind it. A bad seal will allow lubricant from the transmission to flow into the differential over filling and as stated causing problems with leakage into the brakes.

There should be gear oil inside the U joint ball housing. This is what lubricates the U joint and the torque tube bushings. If you notice in the shop manual it says to remove the speedometer gear fitting and add 1/2 pint of gear oil (after the ball connection is assembled). If this is not done and just the transmission is filled the ball will slowly fill, lowering the level of the transmission. Do not install a sealed bearing in the rear location as this would prevent the oil from filling the U joint ball. The level can not over fill as it will just run back into the transmission.
It is not normal for the transmission to jump out of gear that easily, there are worn/defective parts in the transmission.
The best would be to find a used 1954 transmission with all the improvements and go from there..A late 1953 would do but there is no way to determine a late from an early 1953 without disassembly. Second choice would be an arly 1953.
Last choice would be to rebuild yours using the 1953 shafts mentioned + any other parts required. The problem with a 1953 is that there are several different styles of gears used in each one and finding parts may be a problem. If the 1953 main drive gear and main shafts are used they MUST be from the 1st design transmission. If the 2nd design parts are used the 2nd speed gear and syncro. drum must also be used.

Thanks for all the advice. My parts book only runs through '53. I assume that if I were to go by the part numbers in that book, no '54 numbers, I would have the correct conbination of parts, ie early production. The notes therein note that by using the '53 combination of input/main shafts, earlier prolems can be eliminated. How is the driveshaft bushing/oil seal removed/replaced? Also, there seems to be a difference of opinion regarding sealed bearing at mainshaft/rear case. ?? Thanks again,

The late design 1953 parts are not in my April 1953 book either. the change came after that date. You have to have a 1954 or later book to pick-up on this. The late version also had the roller bearing cluster gear and forr lugs on the rings in the syncro. drum. That is why the gear that mate into the syncro. rings are different.
Sealed bearing are unecessary. The factory never used them and the 1949-54 transmissions never had a leakage problem at these points....my opinion. It would cause no harm to use a sealed bearing in the front only. As I mentioned the U joint will recieve no lubrication if a sealed bearing is used at the rear.
To replace the drive shaft bushings get an Oakie Kit from the Filling Station or Chevs of the 40's. The kit supports the drive shaft better and prevents gear oil from passing by the present torque tube seal which is behind the rear drive shaft bushing. To replace the two factory torque tube bushings and seal the drive shaft would need to be removed from the torque tube. This involves removing the ring gear and pinion,etc.

I contacted "The Filling Station" as suggested but they didn't seem to have a clue about the "Oakie" kit. I assume it refers to the front driveshaft bushing, which they have with the oil seal. They also sell, or rent, a tool for removing and replacing the bushing. They weren't real clear on how this is accomplished though. Does the driveshaft have to be removed from the torque tube or can this operation be performed in the car? Thanks, Gene

gpallen2 , Well I would say, not if the bushing on the car is really worn out and there is a good gap between the driveshaft and the bushing then the puller will go right in and easily pull the worn bushing. I have had problems with a good bushing that don't have a big enough gap to push the puller in far enough to grab the back of the bushing. Maybe that was telling me to "LEVER B"!

Tell the guys at the F.S. to look on page 257 of their March 2006 catalog. Thats the latest catalog that I have.

I find it hard to believe that the "Filling Station" has any one working for them that does not know about Oakie Bushings and installation of same.

Well, I've started on this journey slowly and, at almost the first crossroad, I've run into a question situation. U-joint is separated and the driveshaft lowered, however, the convertible X-member prevents it from lowering emough to remove the u-joint and ball housing, unlike that on my BelAir. I didn't run into this before because the drivetrain was all assembled prior to the installation of the body. There's probably a simple solution, not noted in the shop manual, but I took a coffee break to think about this for awhile. Anybody been here before?

First on 1949-52 cars the transmission is remove from on top through the floor. On the convertible the extension on the very rear of the traansmissiom must be unbolted and removed. The ext. that the mount is attached to with two bolts.
Just be thankful that it isn't a Power Glide. :)

Let's face it guys our most patient and competent vendors can't always hire a retired Chevrolet parts man, a Chevrolet mechanic with 50 years experiance that are members of VCCA , one of the premier Chatter Groups and works on 1911 Thru 1980 Chevrolet cars and trucks for a hobby! They are lucky to find one that can crossover parts numbers from the store numbers to a 1928-1954 Chevrolet Parts Catalog! Try to get as many parts numbers,parts discriptions, crossover numbers that you can before calling The Filling Station, just in case some of their 'Older Folks" happen to be gone on a VCCA tour or meet!

:vcca: :vcca: :vcca:

Success!! It's on the workbench at last!! Chevgene to the rescue!! Now the next chapter will be disassembly without all those "special" tools they show in the shop manual. Thanks again you guys, Gene

I tore down the transmission in the 52 using a soft hammer and a brass drift. The very thin nut (left hand thread) in front of the front bearing took a little work but no special tools are needed.

Well, with the help of you guys, the trans is out, disassembled, all new internals, '53 design, and ready to re-assemble. I have a question about "shimming" the trans as referenced in the shop manual. I found two stampings on the bellhousing on the lower two bolt locations, "10" and "5", which I believe indicated the factory shims. If I understand the shop manual, the shimming was based on the original trans case and would have no bearing if a different trans case was used. The case I'm using is not the original and I can find no stampings on it. I'm proceeding with the belief that I don't need to add any shims to compensate. Am I on the right track?

Thanks again for all the help,

That is what I would do, not shim. I haven't shimmed any that I knew had been a replacement transmission. There is a procedure using a dial indicator to check runout, I have never done it.

Seeing you have a mixture of parts I would not shim. The few cars that did jump out of gear did it very infrequently and only under certain conditions. I would wait and see what happens, besides it should not happen with the 1953 parts.

What did you find wrong with the original parts?

Actually, I didn't find anything obviously wrong, although the components showed some wear on the teeth and sliders. The countershaft did show galling, but that wouldn't cause the problem I was experiencing. I took the parts to an old trans man and had him look at them. He examined it all and said he didn't see anything really "bad". The 2nd and 3rd shifting fork did show wear on the contact side. He advised replacing the input shaft and the syncronizer, and turning the fork around to give a new surface, just from my description of the performance. He didn't even think the bearings needed replacement. At any rate, I'm replacing everything with NOS parts plus bearings. Turned out to be a pretty expensive overhaul for a standard trans but I don't want to have to do it again. It apprears that the only difference in the design between the '52 and early '53 is the lengthening of the input shaft to allow for a second set of rollers and the mainshaft to accommodate them. I can see that this would provide greater stability between the two shafts. I feel pretty confident that my problem will be resolved.

Thanks again for all the support,