Hey guys, here's a first for me and I'm stumped. Working on my 68 Chevelle SS resto project. Installed a 396 with a muncie M21 and we fired the motor the other day for the first time (just chassis, no body). Motor sounds great and was running fine and then after about 10 minutes, started to hear noises coming from tranny. It was in neutral the entire time and never put into gear. I have a new flywheel, installed new pilot bushing (steel one), and new clutch. Any ideas? Pulled the tranny and there was fluid around the bellhousing to tranny seal (which I've read may be the shaft leaking), but all else looks good? I even had the rear end off the ground just a bit for safety precaution. After we heard the noise, we shut off the motor and I tried to turn the rear wheels, but the driveshaft wouldn't budge. After a few minutes, they finally broke loose again? Any ideas??? I bought this tranny as a supposed rebuild, and it looks ok..........Any help would be greatly appeciated!!!

Thanks,
iceman46:thumbsup:

The first obvious question is does it have enough gear oil in it? If in fact it does have the proper amount of gear oil and it is a new rebuild then possibly the input shaft was shimmed back to far causing it to bind up when the trans gets warm. Some builders have a tendency to want to shim the input back as much as possible and doing this will not allow enough room for expansion when the parts heat up. Another thought is to also check oil level in the rear differential and make sure the noise wasnt coming from the rearend and resonating up toward the transmission.

I have seen Muncies that were rebuilt with the input shaft torque thrust retainer washer backwards. This happens with unexperienced Muncie builders. Washer is designed to mate with input retainer. If it's installed backwards, it will leak oil and create groves in reatiner, let alone the squeeling noise. Matter of a few miles before it gives out.

Remove (4) bolts from input retainer and pull it forward. Look how the nut is installed. Hope this Helps!

Hey guys, here's a first for me and I'm stumped. Working on my 68 Chevelle SS resto project. Installed a 396 with a muncie M21 and we fired the motor the other day for the first time (just chassis, no body). Motor sounds great and was running fine and then after about 10 minutes, started to hear noises coming from tranny. It was in neutral the entire time and never put into gear. I have a new flywheel, installed new pilot bushing (steel one), and new clutch. Any ideas? Pulled the tranny and there was fluid around the bellhousing to tranny seal (which I've read may be the shaft leaking), but all else looks good? I even had the rear end off the ground just a bit for safety precaution. After we heard the noise, we shut off the motor and I tried to turn the rear wheels, but the driveshaft wouldn't budge. After a few minutes, they finally broke loose again? Any ideas??? I bought this tranny as a supposed rebuild, and it looks ok..........Any help would be greatly appeciated!!!

Thanks,
iceman46:thumbsup:

Hmmmm, the gland nut/oil slinger on backwards, seen that a couple of times, very funny. The wide part goes facing out, the side with the flats to tighten faces in, left hand thread.

It could be a real tight rear bushing. The part about not being able to move the rear tires in neutral bothers me. Some bushings are under size and need to be fitted to the yoke. Wheel cylinder hone will do the trick.

Does the trans spin free with it out of the car????

It's not in two gears is it?
Are the shift levers bolted on the forks? If not install them and make sure they are between the locked detents...neutral. Reverse also.

jim

It's not in two gears is it?
Are the shift levers bolted on the forks? If not install them and make sure they are between the locked detents...neutral. Reverse also.

jim

Think about that, in 2 gears locks up the main drive. It can spin and if it can't spin and you try to start the motor, better have the clutch in and with the body off the car how do you do that???

If in two gears, it locks the input gear as well as the mainshaft. Iceman46 mentions car was running great in neutral, never in gear!

If in two gears, it locks the input gear as well as the mainshaft. Iceman46 mentions car was running great in neutral, never in gear!

Locking in 2 gears locks the trans from the front to the back, nothing spins because one or more gears are locked to the counter gear and it is locked to input and it is splined into the clutch.

I lock the trans in 2 gears on the bench to tighten the gland nut on the front.

Thanks for the education. Pardon my poor choice of words ("LOCKED"). If the shift levers aren;t on the forks they can drop too far back into the side cover possibly causing the syncro hubs to get off center and "ALMOST" lock the trans. It sure makes a noise when the input is spinning.

I kinda sorta thought the point was to help the original post rather bust on somebody else.

Surely you've seen shift forks that would drop back in towards the scyncro hubs.

I imagine that most Muncies were built from the mid 60s to the early 70s at best.

Most are showing their age.

Think about it!

JIM

Well guys, I failed to leave out one small but crucial point - there was no fluid in the tranny when I started the motor. I figured because the tranny was in neutral and I was just breaking in the motor that no gears would be moving in the tranny and that I didn't need gear oil in the trans!!! That may have been a very stupid amateur mistake. So, my next step was to put gear oil in the trans. Started the motor again a few days later, trans in neutral with fluid in it and after about ten minutes, same noise started. I know that neutral works in the trans because the shaft moved freely on the bench and I've been pushing the car in and out of the garage many times. I took the trans out and dropped it off to a friend at a transmission shop. He's going to take it apart and check it out for me. Another thing that bothered me is when I removed the driveshaft to remove the tranny, there was a grove worn into the slip yoke - it's a brand new yoke and I've only pushed the car in and out of the garage!!! :( Wally mentioned something about a tight rear bushing - is this an indication??

iceman46:thumbsup:

Thanks for the education. Pardon my poor choice of words ("LOCKED"). If the shift levers aren;t on the forks they can drop too far back into the side cover possibly causing the syncro hubs to get off center and "ALMOST" lock the trans. It sure makes a noise when the input is spinning.

I kinda sorta thought the point was to help the original post rather bust on somebody else.

Surely you've seen shift forks that would drop back in towards the scyncro hubs.

I imagine that most Muncies were built from the mid 60s to the early 70s at best.

Most are showing their age.

Think about it!

JIM

I was helping and if you think I was "busting" on you you are wrong, just making a point:D:D:D

Well guys, I failed to leave out one small but crucial point - there was no fluid in the tranny when I started the motor. I figured because the tranny was in neutral and I was just breaking in the motor that no gears would be moving in the tranny and that I didn't need gear oil in the trans!!! That may have been a very stupid amateur mistake. So, my next step was to put gear oil in the trans. Started the motor again a few days later, trans in neutral with fluid in it and after about ten minutes, same noise started. I know that neutral works in the trans because the shaft moved freely on the bench and I've been pushing the car in and out of the garage many times. I took the trans out and dropped it off to a friend at a transmission shop. He's going to take it apart and check it out for me. Another thing that bothered me is when I removed the driveshaft to remove the tranny, there was a grove worn into the slip yoke - it's a brand new yoke and I've only pushed the car in and out of the garage!!! :( Wally mentioned something about a tight rear bushing - is this an indication??

iceman46:thumbsup:

The input runs engaged to the counter gear at all times. That is the primary lubrication for the trans, oil spun off the bottom of the case up all over the sides and on to the main shaft and gears. When the trans is spinning there is little to no oil in the bottom. If you ran it several times with no oil it's a wonder it didn't lock up.

It's hard to tell if the bushing was tight or suffered from the no oil deal.

If there was oil in there, when the car was running the trans will spin and cause the rear tires to spin as well, even in neutral. I have seen this numerous times and did it this week when I fired the 62 vette I'm working on, up on jacks, to test the new heater core for leaks. The rear tires roll around slowly.

I wouls pull the trans down all the way, the first gear sleeve needs a good look as well as all the moving parts.

Bet you won't try this again:noway::noway::noway::noway::noway:

Well yes, I think I've definitely learned my lesson and will NEVER do that again. I talked to my tranny guy the other day and we decided to take it all the way down and check it properly. I let you know later this week if it was a costly mistake or not!!!:( Thanks for the help guys!!

iceman46:thumbsup: