The Stovebolt Site Forums The Shop Area Driveline 3-speed tranny condition??

A very kind fellow ‘bolter gave me a 3-speed tranny. He told me up front he did not know it’s condition and therefore would not/could not charge me. Thank you Josh!
I cleaned it up today, then took off the side cover to take a look inside. All the gears looked good and sharp except the largest gear. The teeth look worn on both ends, and several teeth look chipped or broken a bit. I know nothing about transmissions, having never worked on one, but I figure if the teeth are rounded off then the transmission might slip when in gear. Take a look at the pics and let me know what you think. Does it look normal enough to install, or should I keep looking for a better one or have this one overhauled?
BTW, my original tranny is toast. Started jumping out of 3rd gear and now will not even go into 3rd.
Thank you!

That transmission has seen some hard use. Rebuild before using.

I agree with Martin.
Looks like you need a reverse idler and a first/reverse gear at a minimum. Looks like someone has been jamming it into a non-synchronized gear, resulting in chipped teeth.

As stated those gears are seriously damaged. The cluster gear (also known as counter gear) is also damaged where the L/R slider comes in contact with it in the L position. It is likely the most expensive part in that transmission and could be difficult to obtain. It's possible that there are some useable parts like the syncro assembly that you could use in yours.
Fred

Fred is correct. I was confusing the reverse idler with the cluster gear in your photos, but the reverse idler may need to be replaced also. You may be able to get by without replacing the reverse idler, but it needs to be checked. Since you have two trannies, you may be able to swap parts between them to come up with a good tranny.

Does your current transmission's gears look better than this one? Can you use parts from both make one good one?

Good topic. Mine is also showing signs of wear such as jumping out of 3rd under torque. It still runs very quiet though - if that means anything. I am running a 235, but I baby it.
My brother had a 1950 1/2 ton that occasionally jumped out of 3rd and attached a bike inner tube to the floor under the shift lever and would simply reach down and slip the other end over the lever whilst in 3rd.
Worked that way for a long time. He called it a "Tennessee overdrive". I guess I have 200K miles on this one. I looked at the Chevy Assy Manual for a part number and found #3845068 for a LH 3100, but not sure that is correct for mine. Does anyone have a good part number I should look for?

Jumping out of 3rd is usually a synchronizer, input bearing or pilot bearing issue.

That's the part number for the entire tranny. You won't find a new one, or likely even a rebuilt one with that number. You can find part # information here: 29-54 Parts Manual
Some of the vendors carry some transmission parts, although gears are very hard to find, and most bearings can be purchased locally with the PN on the original bearing.

klhansen, Thank you for that link. I have not checked that out in a while. I did climb under my truck to find my tired tranny's part number: 591618. I am hoping you are correct and the synchronizer is the culprit.

Terry

The number you cite is a casting number. It is probably a 591618 which was the transmission case used from 48-54. However, 53 and 54 have quite a few different gears than the 48-52. The later synchronizer has 4 logs while the older one has just two. Two lugs can be ground off and used in the older transmission. However other gears will not mix and match. I haven't built any transmissions in a long time, but if I remember correctly counting the lugs on the synchronizer is the quick way of identifying the transmission. Unless you ran your transmission out of oil, it may not be as bad as you think. Worn shift forks can cause it to jump out of third. A worn out pilot bushing will also do the same thing.

Thanks crenwelge,
The tranny is original to the truck. It was working well when I took my truck down to the frame and over an 8 year period put it back together. At that time, I did not open the transmission, but replenished the lube (90 W) and scrubbed the exterior prior to installing it in my then open frame. The pilot bushing was brand new 5K miles ago. Other than jumping out of 3rd under load, It shifts very well and is quiet. The shift forks condition are unknown. While under there yesterday It does seem to now have a leak. I am wondering if installing a "kit" would help and may be the next option to approach. I may need to make some pins (upper bolt locations) to aid in the removal where they slide back away from the bell housing. BTW Is there a recommended kit I should look for?

Thanks everyone for your comments about the condition of the transmission I picked up. I haven’t looked inside the other tranny because it’s still installed in the truck, but if I decide to take it to a shop for a rebuild I would definitely take them both in with the hope that between the two there would be enough good parts to make one good transmission.

Thanks again for the help!