The Stovebolt Site Forums The Shop Area Driveline 2nd gear clunking

My R10 overdrive transmission started making clunking noise in second gear. Nobody around here will even look at it. Any guesses what could have went wrong.

Worn bearings. Disassembly required.

Ed

Thanks, I'll take a look.

Is this the same transmission for which you posted "3 speed trans noise"?
1st and second gear noise. Goes away when clutch is pushed in?
It only does it when I give it gas?

You need to start the symptom description again and be more specific. When and what does it sound like.

1. Engine running & transmission in neutral. Clutch in and clutch out. Rev engine and any associated noise.
2. Engine running & transmission in 1st/2nd. Truck is on the road. Clutch in and clutch out. Rev engine and any associated noise.

The bearings are usually reliable but can fail if no lubricant or contaminants (chip gear teeth or synchro bits) in the bearings.
If you are sure it's in the transmission then removing the side cover and having a look inside is needed.

http://chevy.oldcarmanualproject.com/booklets/55top13/index.htm

Second gear is on the mainshaft and has the center bearing right behind it. There are 3 bearing in an OD transmission and likely all of them are bad. Other components are worn out as well as no amount of clunking is a good sign.
Some components such as cluster gears and syncros for those transmissions are in very short supply.
Fred

I hate to admit this, but transmission fluid was low. Noise only when transmission is engaged and followed the amount of throttle, in first and second only however. Third and overdrive ok. I found another overdrive transmission and I'm putting it in tomorrow. Im hoping to find a shop to repair the first unit.

I put in my replacement overdrive transmission today, which is a later unit with the support bracket for a cross member. I used the same rear seal as the other unit, but it doesn't seat all the way. There are also half moon cut outs on either side of the end of the tail shaft. Does this later transmission take a different oil seal? Thanks in advance.

The half moon cutouts may be to make it easier for seal removal.

I was a senior electronics "train driver" when I was told I had to cross-train over to become a floor mechanic or hit the door with no retirement. One thing the instructor drilled into my head is to always verify the depth, ID and OD before installing a new seal. With calipers or gauge, check the area with seal removed. Check the old seal. Check the new seal you take out of the box. Check old seal numbers against new seal. The new box could have the wrong seal. If you see any problems, it makes no sense to install the new seal.

Check the online 1927-57 Chevrolet Master Parts book:

http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0335.htm
http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0410.htm

The original seal I ordered online does not have a number on it. I took it to the auto store and had a match, it seemed. New problem is the shift rods hit each other and make it impossible to shift. It's the exactly the same way I had the other unit hooked up. Do I need to bend the shift arms or modify the rods? Going a bit crazy.

Chaz58 Would get on that and look at your planetary gears for wear if they fail may demolish your hard to find parts for O.D. When you put it back together can hold 1-way clutch rollers with a rubber band tie onto rubber band with dental floss to get it out. Or grease rollers,freeze it ,put together while cold. Also look at O.D. of 1-way clutch should be smooth.

Chaz58 You can fix that overdrive get it on YOUR bench read your chilton or motor manuel,we'll coach not hard to work on. On your linkage just solve one problem at a time. Very common to have some clashes on an upgrade,first step is check your length to see if your driveshaft will fit. That's a tuffer problem to deal with,may not be a bolt-up but think it's the same.

I forgot to change the shift arms cover from the other unit. This is my work vehicle so I always get in a rush to finish.