86 Corvette--Jolting Prob..Please Help

KThomp100

My dad's 86 Corvette has started to jolt pretty noticeable when shifting from park to drive. It is idling at about 500-600rpm and a tarns shop could not find anything immediately wrong without tearing apart the whole tarns. They removed the valve body cover and all springs etc are good. Tarns shifts fine during normal use, this is only when going from park to drive and park to reverse although it is not as noticeable when going to reverse. It has also recently begun to idle rough in drive. Car has about 65k on it. Any suggestions would be great. cranny shop estimates about $1000.00 to tear it apart and check it out.

Thanks

lucky20

From your statement, engine performance is in question. Check the obvious first. Check the cheepest & easiest first.

edtlewis

Hopefully the trans shop investigated the u-joints for you before looking elsewhere. If they are worn, you'll get a clunk going for park to reverse or drive. The one I have has 6 u-joints 2 on the drive shaft and two on each half shaft. I just had to replace them at 48K miles. They do get worn especially on Vettes because of the hard driving.

Is it setting codes (Check Engine light) with the rough idle? If not it could be anything. Try a tune-up.

TL

sonjaab

Did anyone check engine mounts, trans mount,
trans crossmember ????? Especially if a youngster
has been whooping on it ?????????

KThomp100

Thanks for the input. I will pass these comments on to my dad but the trans shop says it cannot be the motor mounts but who knows. He wants about $900.00 to tear the trans apart and dad would certainly like less expensive options. I think we will find a frame shop and have them do a complete underbody check.