Hello, I'm new to this, so bear with me. My '92 RS has a vibration at Highway speeds, I've had the wheels balanced, alignment, Which helped but it's still there. I bought the car about a year ago and only drive it when its good weather so I have no idea what maintenence has been done on it. It has about 150,00 mi. on ti any sugestions?

 

There are a bunch of posts on this, depending on it's characteristics. Do some searching and see what you come up with. Having the wheels/tires balanced doesn't necessarily mean that you may not still have a bad tire. Start simple. Bad tire. Bent wheel/axle. Rusted out body. (My wheelwells were rotted out and attributed to some of the vibrations i felt on the highway. Some, not all.)

 

Thanks for the reply. I'll check it out.

 

check your torque arm bushing.

 

before you get too far, there is a problem with the driveline. Hot Rod magazine (I believe) did a test on the factory driveline and at about 65-70 mph they worbble, and flex badly. They tested many many drivelines and everyone of the flexed in someway...some of them even is S shapes. you'll never drive fast again if you see the pics. Anyway there are a bunch of threads about it if you search. I went through the same situation a while back, changed wheels tires all bushings, the whole rear end, etc etc etc.
You need to get an aluminum driveline from a newer lt1 or ls1 camaro/firebird. They are a direct bolt in replacement and I promise it will get rid of your vibration.

Here is a link that is a must read, https://www.thirdgen.org/forums/tran...iveshafts.html this guy replaced all sorts of stuff and then fixed problem with new driveshaft..... and if you read down to my post #19 (near bottom of page) and read his response on post #20....you'll see where he states it's fixed. hope this helps.

 

have you checked the rim's yet? look and see if there are any dents or gouges in them. When I got mine, I was informed that the previous owner had curbed the car a few times, and at higher speeds I can deffinately feel vibration. A tire shop might also be able to check and see if they're bent, les shwaab helped me. also, don't forget to check motor mounts, if they are bad/going bad they may cause some vibration, that has also happend to me. good luck

 

Thanks, for the reply I'll try that first. So I need to get an aluminum drive shaft from an auto lt1 or ls1 camaro/firebird, or does the trans matter? I appreciate all the help.

 

Good info in these threads!!
cfoxworth asks the same Q I ask--

Does the donor trans make a diff, OR just get the LT1//LS1 aluminum DS? I have the 700r4 trans.
Plans are a Bigblock, street driven maybe a few track passes.
Rear is stock, but 4:xx gears will go in with the motor.

 

The aluminum drive line can come from any LS1 or LT1....the line fits 82-02 f-body manual or auto, they are all the same. Mine came out of manual, my car is an auto, there is no difference....just make sure it's aluminum....I believe some lt1 cars still had a steel line..you'll be able to tell difference, aluminum line is much bigger in diameter and of course, aluminum lol. Any year any trany type will fit (don't get a v6 line).

 

Thanks for the info!!

 

I know Im beating a dead horse here. But I snapped my 4th gen alloy dr. shaft in half drag racing. I went and bought a spohn extreme duty steel unit and the vibrations have reared their ugly head. The vibe is bad at 70mph and up, you put the car in neutral at that speed and it gets even worse! Im not understanding why it would get worse? Is this because there is no load on the dr. shaft causing it to act up even worse? I called Spohn and they said there dr. shafts are balanced within 2grams on the machine? Im so disappointed. I cant go back to the alloy because I have since upgraded to a viper output shaft on the T56. I wish someone can give me some good advice. Can anyone recommend a good steel vibration free driveshaft? Im not happy with this Spohn dr. shaft.

 

isnt there somewhere that can put a better balance on em?

 

I guess its worth a shot to take it to get balanced, but from what Ive read in the forum balancing a steel dr shaft hasnt solved these problems.

 

Though smaller in diameter, the alum JG1 (the so-called 1LE) shaft was available in thirdgens. IIRC, the aluminum shaft is three inches too short for the TH350 (with the six-inch tail shaft) and, I 'believe' the TH200C as well.

JamesC