jshepard77

I have a couple of squeaks coming from under my '79 (auto transmission).

One is definitely a brake squeak, and seems to be due to rotor runout. The pads oscillate in the caliper and squeak against the retaining pin. I can see where the pads are wearing on the pin. I think I can fix that with some kind of brake grease on the pin. I'd like to shim the rotor to correct the runout a bit. What should I use for shims?

The more troubling (because I can't figure it out) squeak appears to be coming from the front of the driveshaft. I don't think it's coming from the u-joint. When I put the car up on the lift, I can turn the drive shaft by hand with my head right there and the squeak seems to be coming from the transmission. It almost sounds like it's coming from the rubber seal at the rear of the transmission. It also kind of sounds like it's coming from inside the transmission itself in the same area. I've tried spraying some lubricant on that rubber seal...but it didn't seem to have any effect. There doesn't seem to be any play in the u-joint at all and the noise doesn't seem to be coming from there. Of course I could be wrong. I'll try to attach a link to a picture showing the area where the squeak is coming from.

The squeak is not always there...but is usually there. It is related to wheel speed, and not engine speed. I hear it under 30mph or so, but I think over that speed the wind noise drowns it out. If I put the car in neutral and coast, the squeak remains.

I was initially suspecting the u-joint...but when I put the car on the lift, it really doesn't sound like that's where the sound is coming from. Does anyone have any other ideas? Anything in the transmission that would make that noise? I bought some transmission additive that I was gong to try for the hell of it. I've never changed the fluid in the transmission, but it looks OK on the dipstick.

Any comments are appreciated!



In case that picture doesn't work, here's a link to the pic:
https://picasaweb.google.com/lh/phot...eat=directlink

dgood

do you think it might be coming from the speedo cable...rubbing inside it like it is worn? check that and then drop the pan, see if you can hear the noise better.

jshepard77

Thanks for the advice. I d/c'd the speedo cable and the noise was the same, so I dropped the transmission pan. I hear the noise much more clearly with the pan off. I can't really see much inside the transmission, but the squeak is definitely coming from inside there someplace.

So...what does that mean? The car dives and shifts well, so it's not a function issue...just annoying. Is there some kind of additive I can put in the fluid to quiet it down. This is just a summer cruise car, so if I can avoid a costly rebuild it would be worthwhile.

Any opinions/advise?

jshepard77

More bits of info...probably not significant.

1) I did check the fluid and it was OK.
2) The transmission filter looked pretty clean, except for a dime-sized piece of paper. Looked kind of like "brown paper bag" kind of paper. Not sure where that came from. A couple bits of dirt, no metal parts.
3) The fluid was red...and seemed normal in color and smell to me.
4) The transmission gasket was new. The car is fairly new to me, and I don't know when the transmission was last serviced...but I would guess relatively recently due to the fluid and the new looking gasket.

Not sure that this helps...but I'll throw any info out there I can think of.

Anyone else have this kind of transmission squeak?

hugie82

I would pull the driveshaft and take a closer look at the U jount. They don't need play to squeek. Its rare to have a tailshaft bearing go and if it did you would have found metal in the pan or a leaky rear seal.
Don't overlook trans mounts, cross member, brake cables or anything else that can wiggle at the same rate as drive shaft speed.

jshepard77

Thanks for the suggestion. I just put new fluid in the transmission, along with a bottle of Lucas transmission treatment. Took it for a spin and the squeak is the same.

I think my next step is to disconnect the drive shaft at the forward u-joint and try to recreate the sound by turning the output yoke of the transmission. If the sound is still there, then it's a transmission issue. If not, then perhaps the sound of a bad u-joint is being transmitted into the transmission...I read someplace that this could happen.

If that doesn't yield any results...I'll get earplugs.

1979VetteGirl

I know this thread is a bit old, but I am having this same problem on my 79 vette, it is also an auto trans, and I was wondering if it ended up being a bad u-joint, or something with your trans. Any input would be a HUGE help!

jshepard77

I never did find out what that squeak was/is. I don't put a lot of miles on the car, and haven't really noticed it much the past few times I've driven it. I think it's still there, but I've just lived with it.

I don't remember if I ever did what my last plan was (disconnecting drive shaft and isolating the transmission from the rest of the drive train). But if I were to tackle this again, that would be where I start. Then I would know if it was something in the rear drivetrain (u-joints, differential, wheels, etc) or the transmission itself.

Sorry, that's not much help...never did figure it out.

Big2Bird

Speedo cable/drive gears? I would pull the cable and see what happens/.