My 89 IROC has a clunking, rubbing sound that has come back. I heard it once the day after I bought the car last November but it went away and now has done it 2 out of the last 4 times i've driven it. Very loud, sounds like the rear end is coming apart. Seems to be more on the left side rear and "feels" like something rubbing (driveshaft?) . I think maybe when automatic transmission shifts from low to 2nd. We put the car up in the air last week and checked the differential fluid level, the axles, brakes, u joints felt ok. Any ideas on what to look for or what next steps should be. Thanks

 

Hows the transmission mount look? When they get really bad, it'll feel like a mule is under the car kicking you in your hip when the trans shifts hard into second.

 

I didn't check that. I'm not sure i would know what to look for, thanks.

 

When you look at the mount, you'll probably know. Or you can lift the trans a bit and if you see through the mount... LOL It's usually pretty obvious, but the weight of the trans can hold the two halves of the broken mount together. Very, very, very common in these cars because the torque arm is mounted to the trans, so they're under a lot of stress.

 

Thanks Drew, I will see if we can get some time at a friends shop to put it on a lift this week.

 

While Pat is under the car, he might check the torque arm mount as well as the parking brake cables. I've seen this latter so loose that they can actually groove the drive shaft. If it's the trans mount, I'd avoid the OE Anchor version and go with beefier rubber:

Napa DTM 6441261/$19.79
O'Reilly PowerTorque A2672/$11.99
AutoZone Duralast A2672/$10.49 (In the note of this latter, it says "With Sport Shift—whatever that means)

JamesC

 

Thanks James, now if I can just get him under the car.

 

Frankly, I'm surprised, ahem, that you yourself don't crawl under there. Shoot, I'd be ready with both my camera and EMT's on standby .

JamesC

 

When I looked that one up on AutoZone's website, it says that it does not fit my '92 T/A. But it does say it fits a '92 Camaro, although only the V6. Their website makes no sense sometimes. I thought the tranny mounts were pretty much all the same for automatics.

 

I note that both the Duralast 2672 and the Duralast 2394 will fit my car while only the latter will fit yours. If both will fit mine, I can't imagine why they won't fit yours. For more accurate info, you might check RockAuto.

BTW, Black, is there any chance that many years ago, I sold you an alum drive shaft?

JamesC

 

I don't trust the fitment option at face value at all. I just found it amusing that it said it didn't fit my car but it did 1990 through 1992 Camaros. The funny part was that the only year of Firebird it did say it fit was the 1993 year. Huh? OK.

Yes, I did buy an aluminum shaft off you....years ago. Like, YEARS ago. IIRC, it was probably around 2000 or 2001. Still on my '91 GTA all these years and two pinion yoke replacements later.

 

One thing I forgot to mention is that the noise doesn't happen all the time, just sometimes.

 

At any speed or just when you "get on it" a bit?

JamesC

 

Pretty much just normal acceleration, happens a couple or few times and then doesn't happen for a while.

 

Bumpy roads?

JamesC

 

All kinds of roads but did notice once on bumpy stretch, happened the other day after leaving your house, happened leaving Slimmers Friday after getting the new starter installed. Probably try just showing up with the car and hope he can make time to look.

 

Went to the shop and Pat drove the car (no lifts available), tried tight circles to check the limited slip, hard acceleration, normal acceleration, start and stop, thought he might induce my vertigo but no noise from the car or me. Guess have to wait for a time they can get it in and up in the air and hope Pat can find something his guy didn't.

 

My apologies to James, I got under the car and crawled around checking stuff after you left, no cameras and no EMTs. Found nothing loose.

 

 

nope, keep looking around under the car but not finding anything loose, need to get it on a lift.

 

Whatever was making the noise probably fell off the car.
Problem solved.

 

i would be thrilled if that were the case but i don't think that kind of noise.

 

well, i stuck my phone under the car to take a picture since i could see some sort of fluid on the bottom and this is what i see. really like to get it on a lift so maybe i could tell what's leaking. I know, crappy photos that don't seem to tell me anything but general idea of something maybe?

 

Now you have to use your 5 senses - stick a finger in it (TOUCH) and then LOOK at it, SMELL it, and maybe TASTE it.
I guess there is nothing to HEAR.

Unfortunately, I can't tell what it might be from those pics.

 

yep, lousy pictures. My mechanic says he will have a lift free tomorrow so hope to get under it and look and feel and probably not taste but move stuff around and hope to find something loose.

 

Put it on the lift this morning, looked around and we can't find anything obvious, transmission mount is good, nothing appears loose underneath. Pinion seal is leaking so needs replaced. Pat says next step is to pull cover off rear end and look (will replace seal then too) but he didn't have time today so I guess I still know nothing.

 

Finally! Got it up on the lift and pulled the cover. Everything looks/feels ok, said clutches a little worn but normal/common. Pat made the decision to just change the fluid and add some posi lube and not replace the leaking seal until finding out if this solves the noise problem, i understand it was because he had other things he would rather be doing. Lucky for me I was able to arrange a technical advisor to stop by. James C couldn't stay away from the bottom side of a third gen. All back together and I guess see if the fluids solve the problem.

 

Glad to see you photographed my best side Were you surprised at the gearing?

JamesC

 

I was, 2:73 seems strange for an IROC.