I'm trying to pinpoint my problem before spending money and time. I have a severe vibration that goes though the entire cabin at 72 mph and on in fifth gear at 2200 rpm.
If I take it out of gear the vibration goes away.
If I take go to the same speed in 4th gear, it is silky smooth.
At the same rpm in 4th, I don't have a strong vibration (maybe very slight but that could have been the road).
These symptoms have me believe that it may be fifth gear related; however, I am not exactly sure.

 

id check your tranny mount also,it may be wearing out and could be causing the vibrations

 

u joint or slop in the output shaft is what i'd check..

 

Haven't drove the car in two weeks so I haven't had a chance to try anything yet.

If it was a transmission mount wouldn't the vibration be the same in any gear at that speed.

I'll have to get under there and look for potential causes of vibration.

 

thats what i thought,id drive for awhile and it would be fine but when id decelerate id get alot of vibration and i thought it might of been the shift kit but sure enough it was the tranny mount,also broke 2 shifter cables in the process,not sure its thats the case with yours since its a manual tranny

 

any luck yet?

 

We keep having winter weather whenever I could be driving it. And on the rare nice day I am working. So its almost been a month since I've driven her.
Anyone know if 5th gear has its own bearings that tend to wear out?

 

My car has that same vibration. It happens in fifth gear, and is barely there at 70mph. It gets very noticible at about 73mph, and annoying at 75. By 85mph, the car feels like it is going to shake apart. Also, the vibration gets faster as the speed goes up.

I thought origionally that it was out of balance tires. But the weights look brand new leading me to believe they were just balanced. I never did get a chance to balance them myself tho, I quit my tire job too soon.

Also, I have no idea weather my car does it in another gear or not. I will try this. But any solution would be nice, thanks.

 

Well, the other night I started taking the transmission out to replace the clutch. In doing so I found that one of the u joint bolts was lose by 2 revolutions. It didn't seem like the driveshaft had any play from underneath the car. However, at 70+ mph it may have been a different story.

Also what ujoints should I use for my car. I have a 2000 Aluminum Driveshaft with 1986 rear end. The catalog of u-joints have a couple different listings for various years/ driveshafts.

 

Humm, did the U of the 2000 shaft fit the pinion yoke of the 86 perfectly? If the LS1 and JG1 shafts have the same U, I'd expect you to have a mating problem with the 86. The P/N and some info are included in the following link:

https://www.thirdgen.org/forums/tran...light=carquest

JamesC

 

Well, the u-joints seem to fit fine into the yoke. But I've read a couple posts about requiring different u-joints when dealing with separate applications, so it was just to confirm.