Smokie20

i have a 93 z28 and it is a manual. now my question. last week i was driving and i was cruising at 50 mph just normal driving and then out of nowhere the car jerks. the only way to describe it is that it felt like the transmission was getting caught on something. its like a quick hard jerk. and then i here a noise from the transmission. i just thought it was a one time thing and thought nothing of it but recently it has bee doing it more often. Any ideas on what it could be? maybe i just shifted to early and i was in to low of a gear? Any answers will help!

Injuneer

What gear were you cruising in when this happened? What was the approximate engine RPM? Are you sure it wasn't an engine stumble or misfire?

Fixed the "topic" - I assume you meant "transmission".

Smokie20

i was in 6th gear and the RMPs were at about 1400. and im pretty sure it was more then just a misfire. it was like you could feel the transmission move or something. Another thing that i just thought of. when i went to have the car looked at for the exhaust it was on the lift and the exhaust was really close to the drive shaft. Is that normal or could that possibly be the problem?

JakeRobb

I'm with Fred on this - probably a misfire.

When the rear suspension is fully extended (which it would be when up on a lift), it's normal for the driveshaft to get pretty close to the exhaust.

Injuneer

Running at 50 MPH in 6th gear is not a good idea.... that is "lugging" the engine at low RPM, and places a lot of stress on the ignition system. If you have a weak component in the ignition system, it's going to misfire and buck. 6th gear is intended for high speed cruising on the freeway. Both 5th and 6th gears are overdrive, so you want to use 5th to keep the revs up a bit higher.

Next, if the transmission seems to move around a lot, check the transmission mount, under the tailshaft housing of the trans. May be broken, allowing the trans to lift off the cross-member when the torque arm reacts to driveline torque. Broken trans mount is very common problem.

Yes, the exhaust is very close to the trans tailshaft housing and the driveshaft. Exhaust should be held ridgidly at that point by the bracket that supports the catalytic converter. The proximity of the exhaust should not be causing your problem.

moparman

In my 6 speed Formula, 55 mph is the slowest I'll drive in 6th gear. Below that the engine is lugging and it feels like it's bucking and missing a bit.

Smokie20

Im glad i asked. and yeah i think i was just shifting way to early. This being my first manual car i was unsure of when to shift into 6th gear. i will take a look at the trans mount this weekend just to be sure that it isn't the problem. Thanks for all the answers!