65Z01

I have an '88 Vette and an '88 IROC-Z; though the question concerns the A4 in the IROC-Z I thought it might be pertenant here too.

About a year ago I purchased the IROC-Z on ebay and was told to not put the shifter into 3rd gear as it would result in some "noises". So I had always started out in 4th, until two days ago that is.

I mistakenly put the shifter into 3rd gear before pulling out of a parking lot and began to hear "grinding" and/or "scraping" noises, both upon start up and under very light throttle. And there was hesitation of acceleration under light throttle.

At first I thought it was a front wheel scraping on the fender as the car shuddered but, when the noises continued in straight line motion, I began to think of an A4 problem. I checked the shifter position and noticed my selection error when stopped at a traffic signal. After moving the shifter into 4th bear operation was once again smooth, effortless and acceleration was strong.

I thought the A4 moved through the gears till it hit the top gear of the shifter position. In such case, what can be the difference between putting the shifter in 3rd gear or 4th gear???

BTW, I have never started out in a lower gear due to the warning of the former owner.
Also acceleration is very strong even with the LB9 engine, shift points feel normal and even forced down-shifts on the highway feel normal.

Pete, do you have any clue why driving in 3rd gear vs 4th gear could make such a difference.

Pete K

Off the top of my head, I would think the problem is in the input drum. The overrun clutches and forward sprag are on in the lower gears. Although neither typically cause the problems you describe.
Very unusual.

65Z01

Aaaah so there is an internal difference between starting out in 3rd vs 4th, in which case I should avoid starting in any gear other than 4th.

Thanks Pete.