I am fresh out of ideas and patience with my E30. It's had driveshaft issues for a while and I can't figure it out. Any help would be greatly appreciated and keep me from setting it on fire.
It vibrates pretty bad past 70 mph and only gets worse as speed increases. It's speed dependent and nothing to do with engine; trans in neutral and vibration doesn't change.
The backstory: I got a junkyard 87+ eta trans a year ago with some issues I didn't realize at the time. I think the output shaft was a little bent from the getgo. I also got a serviceable driveshaft from an E30 parts shop for cheap, which ended up being imbalanced and having junk ujoints. I replaced the ujoints and had the shaft balanced. Still vibrated pretty bad, but the trans output shaft was visibly bent by this point. I broke the giubo bolts at least 5 or 6 times before the trans bearings started screaming under boost. I got a one piece driveshaft from driveshaft shop and had to space the diff off the subframe with the oem washers to get the diff adapter to clear. Driveshaft vibrated at 70+ mph, so I took another look. While I was at it, I replaced the diff and transmission with fresh ones that had no issues. The car shifts great and there's no more noise or excessive lash in everything. However, the driveshaft vibrates pretty bad at 70+ still.
I tried rotating it 180 degrees and rebolting it to the rear adapter and spacing the diff with a second set of washers just in case the driveshaft ever moved enough to hit the subframe.
In theory, the bushings and washers would only move the diff vertically and retain the alignment with the transmission, so the angles would be complementary.
I checked the motor and trans mounts and they seem fine. Poly motor mounts with maybe 8k miles on them. Rubber oem trans mounts that look good. I have lifted the motor and let it set a couple times with the mount bolts loose to swap oil pump and relief valve, but I didn't see any alignment dowels on them, just solid poly cylinder with a bolt in the center.
With the original driveshaft, I had the car up to 140 before and had no vibration. Now, I'm worried to take drive take it up to 70. Is there something I'm missing?
It vibrates pretty bad past 70 mph and only gets worse as speed increases. It's speed dependent and nothing to do with engine; trans in neutral and vibration doesn't change.
The backstory: I got a junkyard 87+ eta trans a year ago with some issues I didn't realize at the time. I think the output shaft was a little bent from the getgo. I also got a serviceable driveshaft from an E30 parts shop for cheap, which ended up being imbalanced and having junk ujoints. I replaced the ujoints and had the shaft balanced. Still vibrated pretty bad, but the trans output shaft was visibly bent by this point. I broke the giubo bolts at least 5 or 6 times before the trans bearings started screaming under boost. I got a one piece driveshaft from driveshaft shop and had to space the diff off the subframe with the oem washers to get the diff adapter to clear. Driveshaft vibrated at 70+ mph, so I took another look. While I was at it, I replaced the diff and transmission with fresh ones that had no issues. The car shifts great and there's no more noise or excessive lash in everything. However, the driveshaft vibrates pretty bad at 70+ still.
I tried rotating it 180 degrees and rebolting it to the rear adapter and spacing the diff with a second set of washers just in case the driveshaft ever moved enough to hit the subframe.
In theory, the bushings and washers would only move the diff vertically and retain the alignment with the transmission, so the angles would be complementary.
I checked the motor and trans mounts and they seem fine. Poly motor mounts with maybe 8k miles on them. Rubber oem trans mounts that look good. I have lifted the motor and let it set a couple times with the mount bolts loose to swap oil pump and relief valve, but I didn't see any alignment dowels on them, just solid poly cylinder with a bolt in the center.
With the original driveshaft, I had the car up to 140 before and had no vibration. Now, I'm worried to take drive take it up to 70. Is there something I'm missing?
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