Mystery Drivetrain viberation revisited.

Steven242 · Post by **Steven242** » 21 Mar 2009, 06:25

Alright, many of you may know the story of what I did a month or so ago with running my transmission too low on oil.

Thing is, I don't think it is the transmission anymore. It still shifts fine, but that same old vibration is still there at LOW speed. I mean really low speed, bout 10mph or less. I'm looking under the car this morning, and trying to find loose parts. Find out that the leak is gone! still has oil, but leak is gone. Grandpa told me to dump a can of Brake fluid down the tube of the trans, and it worked. He said it is an old man's trans fix, and the best leak stopper out there. Anyways, My rear axle was quite hot to the touch where the pumpkin is after driving for a few miles. I'm wondering if when that thing heats up if that is where the vibrations come from. Because it only vibrates when things are at running temp. And when the vibes start you can watch the auto shift lever MOVE an inch each way back and fourth, and I took the hood off the other day and the engine was doing the same. I don't think a bad trans would be causing stuff to bind up the way it feels like it is.

I'm thinking the exhaust shop may have dealt me a bad hand when they ran the exhaust pipe over the axle, instead of under.

Could an overheating center chunk cause itselft to bind up at low speeds?

Any ideas at all? I'm at a point of Total Confusion Daily with this car.

DeRail · Post by **DeRail** » 21 Mar 2009, 10:00

It could be the center carrier bearing on the driveshaft causing some problems, but with the shifter moving the way it is, I'm almost inclined to say that the transmission mounts may be at fault.

Post by **billofdurham** » 21 Mar 2009, 12:46

+1.

I'm thinking the exhaust shop may have dealt me a bad hand when they ran the exhaust pipe over the axle, instead of under.

The pipe should go over the axle.

Bill.

Steven242 · Post by **Steven242** » 23 Mar 2009, 04:03

billofdurham wrote:+1.

I'm thinking the exhaust shop may have dealt me a bad hand when they ran the exhaust pipe over the axle, instead of under.
The pipe should go over the axle.

Bill.

The original exhaust was on the car when I got it, and it was run under. there is almost no room above the axle for the exhaust pipe to run.

so the center carrier bearing and maybe the mount for the transmission may be the issue?

Post by **billofdurham** » 23 Mar 2009, 13:39

The original exhaust was on the car when I got it, and it was run under. there is almost no room above the axle for the exhaust pipe to run.

Was it the original exhaust at that age? I have not had a 242 but I have owned mosty rear wheel drive vehicles for 48 years and I have never seen an exhaust system that went under the rear axle.

The most likely causes are the centre carrier bearing and transmission mounts.

You say the diff is heating up. Have you checked the fluid level in it?

Bill.

Steven242 · Post by **Steven242** » 24 Mar 2009, 15:39

Have not checked the fluid, been meaning too...

I can snap a picture of the rear end if you'd like, but the antisway bar that runs across the rear axle has a bend on the right side where it goes from running level with the bottom of the axle to center, then back down to bottom, and the only thing that wasn't original on the exhaust for its age was the rear muffler.

I'm thinking that maybe my carrier bearing may be going out, and along with the trans mount being a little soft is causing the shake at low speeds.

As for the diff heating up, I'm hoping the exhaust pipe isn't run too close to the axle.

Post by **billofdurham** » 25 Mar 2009, 13:15

No need to crawl under the car with a camera. The attached shows the rear anti-roll bar and the exhausts fitted the 1978 2 series.

242 rear susp and exhaust.pdf: (741.17 KiB) Downloaded 134 times

The exhausts show two middle to rear boxes and pipes, parts 20; 27; 21 and 28. Looking at 28 it would appear to be designed to go under the axle whilst 27 is designed to go over the axle. I had a chat with my local exhaust supplier today. Parts 21 & 28 are no longer available in the UK so it may be the same over there.

I don't think enough heat will transfer from the rear pipe to the rear axle to heat up the diff, even if the pipe was in constant contact with the axle.

Bill.

Steven242 · Post by **Steven242** » 25 Mar 2009, 18:05

I finally was able to get under the car today to check out the drive train... I had a coworker hold the brake, ebrake up, and shift from N to D and back to N then to R I didn't notice much play from the trans like the mount was going, nor from the carrier bearing. but I did notice that each time it was shifted the driveshaft rotated about an eighth to a quarter turn. Maybe my rear gears are getting really worn out and could cause shaking/vibrating at low speeds? Or am I just needing to rip it all apart to find this thing?

Steven242 · Post by **Steven242** » 31 Mar 2009, 16:16

Alright, one last question... can someone tell me what size u joints and center carrier bearing I have, I'm going to be ordering the parts to get my drive shaft fixed, and they list two sizes... but not showing if one is for manual or auto or what... they just say for the carrier bearing 44.5mm and 50.8mm and the ujoints I forget the size.

MasterBlaster · Post by **MasterBlaster** » 05 Apr 2009, 16:30

each time it was shifted the driveshaft rotated about an eighth to a quarter turn. Maybe my rear gears are getting really worn out

No oil in the diff = friction, heat, worn gears, and "play" in the driveshaft (there should be almost none) where it enters the diff. Instead of smoothly meshing and rotating, the gears are likely so worn that they "leap-frog" from tooth to tooth, and could cause your vibration at "really low speed, bout 10mph or less".

Grandpa told me to dump a can of Brake fluid down the tube of the trans, and it worked.

Brake fluid is for brakes. The only way it can "stop" leaks in a transmission is by attacking the seals, and swelling them up. They will slowly turn to mush, and one day suddenly fail when you're 100 miles from home.