Hey guys,
I sought out this forum after I started having some trouble with my 1999 Monte Carlo z34 in the hopes that someone might have had similar issues.

Recently I noticed after driving for about an hour, my car started to shift a little rough and bog ever so slightly going up hills. Since I commute to school driving about 2 hours a day I'm quite familiar with the way it runs. So when it starts shifting rough, it gets progressively worse. If I try to downshift into a lower gear, say down to 3rd gear at 45mph, it clunks hard into 3rd making a terrible noise.

Also, just in case it happens to be related, last summer my airconditioner stopped being able to switch from face to vent to feet and is permanently defaulted to defrost and feet (I've read that it defaults here for safety reasons in order to enable the driver to defrost the windshield, and happens potentially due to a loss of vacuum).

I know I'm new around here but I'd greatly appreciate any suggestions.
Thanks!

- Ryan

 

Since you are having trans problems and its bogging under load, I would say your cat is probably clogged.

Your vent problem does sound like a vacuum leak. Most likely unrelated to your shifting problem.

 

Vent= vacuum leak... check all vacuum hoses for cracks. Or small holes. ( the way most of these things are routed under our hood, I have had to fix many hoses just from years of rubbing against something.

As for the bogging, could be the cat... the hard shifting part could also have something to do with that, but id actually check the trans fluid... make sure it doesn't smell burnt or anything. Nor look burnt. The hard shifting happened on mine after warming up due to a clogged trans cooler.