VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1937, 3 speed passenger transmission

Hi all,
due to growing gearbox noises and second gear shifting problems i decide to tear my transmission apart yesterday. After a first rough appraisal of the parts the Clutch gear bearing and the rear bearing gives me the most concern. I learned from the shop manual that i have to use a puller to pull the clutch gear bearing from the case. When i disassembled the clutch gear bearing from the case a puller was not necessary at all. There is rather a loose fit than a press fit between the bearing and the case. And that’s the same for the rear bearing. I got also the impression that the two bearing shells have too much play.
I would really thankfully for the slightest answer of the following questions:
1. Is the loose fit between the bearings and the case ok? The case seems to be ok, no cracks at all!
2. How about the play between the bearing shells?
3. Does someone know where i can get parts especially bearings, synchronizer rings and brass cone rings?
4. The brass cone ring (second gear) sits loose in the second and third speed clutch. Is it possible just to replace the cone ring?

See forward hearing from you!
Thanks a lot
Robert

The bearing to case being a neat fit but not moving in the opening I dont think is a problem but if it is moving in the case it could be a problem. As for play between "bearing shells" if you mean the inner and outer ball race I would replace the bearings.
Tony

sorry, but just another question entered my mind:
1. Are the brass cone rings pressed into there hubs of the second and third speed clutch or do they sit loose in the clutch?
2. Should the shift resistance between the energizing spring and the synchronizer ring for both gears (2 and 3 gear) the same. In my case the resistance for the second gear is much weaker. That would fit to my problems shifting into the second gear.

Hi Robert,

I have a couple of comments to help you. First have you a support system in Germany/Europe to help with questions? Some of the Chevy guys there should be helpful. Alligator (Andre Ruiters in Ostfildern) has rebuilt his 1940 transmission. germanchevy is Stefan in Bad Reichenhall. He also has a 1940 but, I think, used to have a 37.

Second, You need to be doing searches of our old posts on repairs you want to make. The following link will help you get started. If it is confusing then follow the directions under Advance Search, or type in Transmission as a Search Topic and under Display Name type Mike Buller. Eventually, as you master the Search process, you will be rewarded with a lot of information on the repair you want to make.

Search Function Tips

Last, finding the brass synchronizer cones/rings may be very hard. Keep looking on Ebay and post in our Parts Wanted Forum. The Filling Station used to carry them but I do not see them listed in their on-line catalog.

1940 Synchronizer Rings

41 Transmission Removal Part #1
41 Transmission Removal Part #2

Good luck, Mike

P.S. Robert, you have never told us why you decided to take your transmission apart? You seem to have gone from asking about transmission fluids to major surgery? More information would be helpful.

Finding a new synchro drum is difficult. I had an NOS drum installed and it has caused problems. It looked slightly different in that the one end was welded. I will be replacing it with a used one.

Hi Robert,

I am not a mechanic but have some experience with disassembling 41 transmissions. The same column shift transmissions were used from 1939-1948. I videotape my work so even have good footage on how things go together and come apart. I have several extra transmissions so can take them apart to scavenger parts or better understand how they work. I highly recommend you document how you disassembled your transmission since I think it may be sometime before you locate parts and reassemble it.

I hope you have had some time to look at some of our old posts on this topic. I, unfortunately, think you should assume that you will not find replacement parts for your brass synchronizer rings. At best you may find a set after a lot of searching. My advice is to try to replace the worn parts that you can easily locate. Go ahead and replace your bearings. A good local supplier of bearings in Germany should be able to replace them. If not I or someone else will volunteer to locate them for you and send you a set. Look carefully at each gear for damage or extreme wear. Some of our posts show passenger drawings of the parts with the correct names and part numbers. Be careful if you do not have a column shift transmission. Most of the parts are the same for the floor shifting transmission but double check each part for compatibility.

I would be very concerned with the wear of the yoke. I see new yokes for sale on ebay a lot. This post will describe yoke wear problems Double Clutching and Grinding. It appears that the yoke on a car that shifts on the column rests on a guide bar while the one on a floor shift rests on a shaft? Is your transmission set up for a floor shift or column shift?

The brass synchronizer cones were originally press into the clutch. If you need a closeup picture I can provide one. The picture will show that the brass cone has small indentations/punch marks in it used to set the cone permanently in the clutch. Replacement cones either need to be punched or glued in place. I know at least two regular posters (Aligator/Andre in Germany is one) that glued his in place. Personally, I am suspicious that this could/would work!

As I understand it, originally the brass cones were sold as part of the clutch assembly so not available for individual replacement. So in the best case scenario you will locate a NOS clutch and pay accordingly for it. My transmission also needs rebuilding to eliminate the grinding I get when shifting into second gear. I have been collecting parts for 3 years to rebuild mine. Fortunately, I can double clutch to correct the grinding 90% of the time. I also live in a community that I can get away with accelerating slowly. Most of the streets are posted at 35 mph.

Best wishes, Mike

P.S. Yoke on ebay for sale I think this is for your transmission. I could bid on it for you? Here is another one. Yoke #2

Hi Robert,
restored my 40 Transmission in 2013
Post
Don´t know how much parts are the same. The synchro rings i got from a vcca Chatter, but they are also on Filling Station part RW-453. For the Rest lets talk in German about PN

I just removed the brass ring from one end of my old synchro hub. I broke the ring in doing so. It was held in place by five copper or brass pins.

Robert,

GM did not sell the brass synchronizer rings separately. They were part of the synchronizer clutch assembly. For your transmission, you need GM Part No. 602339, which is the 2nd/3rd speed clutch assembly and includes the tapered steel synchronizer rings and their retaining rings. This one assembly will almost assuredly cure any gear clash problems you may have been experiencing during shifts into 2nd or 3rd gear, assuming your energizing springs on the 2nd and 3rd gears are OK.

I have seen these come up on Ebay occasionally. The price seems to range from $75.00 to $400.00, and the condition of the part can vary. Avoid one that has a great deal of rust on the clutch gear. If you do find a NOS clutch assembly, the steel synchro rings are likely to be stuck in the tapered brass rings. Be sure to free these up and lubricate them with oil before trying to assemble the transmission.

Mark

I will overhauling a 37 Tranny, too.
I noticed that these rings sit very strong.Why? How can I free these rings up? Hammer? Washing with ethanol?
Thank you!
Tino

If you look at the end of the hub that doesn't have the shift ring, you will see holes in the hub that have pins that hold the ring in. If you drill those pins out, the brass ring will fall out.

More info on Syncronizer rings. Mysterious Syncronizer Assembly

Mysterious!!!

Tino,

There may be some confusion in terminology of the parts on the 2nd/3rd speed synchronizer clutch assembly regarding the synchronizer rings. The bronze female tapered rings are permanently installed into each end of the sliding gear and were not serviced separately by GM. The male tapered steel rings fit into the female bronze rings and are held in place by a spring steel retainer ring. These male steel synchronizer rings with retainer rings were available separately from GM. When assembled correctly, there is sufficient clearance between the male and female rings to allow the male rings to turn freely. If you push the male ring into the female ring while turning it, the male ring will lock up. This is what it is supposed to do in service and is what causes the gears to "synchronize".

If your male rings are stuck in the female rings, clamp the sliding clutch gear assembly in the vice, using soft jaws to protect the surfaces of the external gear teeth. Using a long pin punch, reach through the bore of the clutch gear and tap lightly on each of the three internal lugs of the male ring on the opposite end. This should free the ring up and allow you to turn it and get some oil on the conical surfaces of the two rings. Repeat the procedure for the other end.

Mark

Thank you! Job done!
Tino

Looked at my saved Links from 2013. Found this seller http://www.vapinc.com .
Offers many Parts for the Transmission, also Sychro Rings and the Sliding Clutch complete
http://www.vapinc.com/chevy/main.html

The site Andre is posting is for Vintage Auto Parts. They do have the complete Syncro Sliding Clutch for sale but this clutch is only appropriate for 1937-39 transmissions. They advertise syncro transmission rings for 37-54 passenger car and truck transmissions.

Good luck, Mike

Hi Mike,
Roberts is a 37 Transmission?!

Hello all,
first of all thanks a lot for your comments. Excuse me that I didn’t come back earlier but seeking parts kept me busy. The part which confuses me most is the >>Reverse Idler Gear Countershaft <<. I learned from a part-number catalog that for a 1937 passenger transmission the shaft has the following dimensions and characteristics:
4.428
590827
7/8 diameter
7 3/32 length 2 flat oiling slots and 3/16 hole (for use only bushed type counter gear)
37-39 pass. and comm.

The 3/16 hole gives me headache because the shaft which was installed in my tranny has no cross-hole at all. The flat oiling slots look also rather sloppy carved. Does anyone know more about the shaft and its further development over the years (37-53)? Or did i even screw up finding the right part number?
It is also hard to find a 590827 shaft! Does anyone know a source where I could get one?
Sorry, but just one more question. Are there catalogs available with interchange numbers (GM <-> other vendors)?

Thanks a lot for your help!
Robert


@ André: Thanks for your messages. It would be great getting in touch with you as soon as i will start to reassemble the tranny
@ Mike: Thanks for your response and the offer to volunteer if i am not able to find the bearings in germany. It turned out that that was the easiest challenge so far.

590827 is the shaft for the cluster gear. Fits all 1937 and up 3 speeds with the bushing type cluster gear.
590831 is the shaft for the reverse idler gear. The reverse idler gear requires the pin that goes through the case.
They alll (years) use the same pin.