When i take off in first and shift to second there is a slight clanking sound. What could it be?

 

I've been having a problem with my car lately as well, hearing a "clunk" or "clank" sound in the back. I just took it to the dealership yesterday, and one of the mechanics said I just need to do a "differential service" ---> change the oil in the diff?! Apparently he has a Camaro himself, and has the same problem, and doing a service will get rid of the noise. He said the noise is something to do with the posi unit? It sounds almost like a worn out universal joint though?!

I know your car is an M6 and mine's an A4, but for me the problem happens mostly after the car has shifted into overdrive and it's under no load, then when I hit the gas to accelerate, I'll hear the "clunk". If you hear it between 1st / 2nd, it's probably because you're off the gas for a second and clutching (so there's no load on the car) then applying the load again?

Maybe others have had similar problems?? That's what mine is though, and it may be the same thing? I plan to "service" the diff when I change the gears in a couple weeks.

 

its a common problem.

i asked about it b4, and was lead to belive its just "normal".


at what RPM do u usually shift into 2nd??

 

just out of curiosity how many miles do you guys have on your cars as i would think that if you had a generous amount of miles on your z's that they could be overdue for the rearend oil change. but regaurdless of that i would go ahead and change the oil anyways because if you do and see metal fragments in the oil that would tell you that your rearend is messed up and needs a mechanic's attention. i don't know about you guys but i'd rather find out that i have a bad rearend now than be driving down the road 5,000 miles later and get stuck because the rearend seized up. but it sounds that theoretically it could be just about anything from the tranny back. could be something as simple as a loose bolt on the u-jount or could be something as hard to find as a tiny crack in the axle. just my .02 even though i'm not a mechanic.

 

1st - 2.66
2nd - 1.78
3rd - 1.30
4th - 1.00
5th - 0.74
6th - 0.50

I guess 2.66 --> 1.78 is a fair drop? but it's nothing compared to the split between 1 and 2 in the A4 tranny!!

1st - 3.06
2nd - 1.63
3rd - 1.00
4th - 0.70

 

My car has 32,000 miles on it. What kind of gear lube should i use. I heard that gm made a good additive for these rear ends. Appreciate the input.

 

Yeah, I believe that GM does make an additive for the posi rear end..............I was told by the service guy at the dealership last week that I should use the additive as well as change the oil in the diff to quiet the noise in there.

 

I had the same problem with the noise.

Turns out, my axle was BENT! I had to get a new one.