Driveline woes.

[Inline Sex]

I'll try to make this short and simple. 89 325i M20 5Spd

My car needed a new tranny and clutch. There were no noticeable vibrations at any speed under any load, just had no 3rd gear and 2nd wasn't far behind.

Mechanic installed good used tranny, new clutch, step-cut resurfaced flywheel. Also installed E36 M3 Shifter, new CSB, Flex disk/guibo,and new Tranny mount. In order for the shifter to fit, the vibration dampener had to be removed.

Now the tranny feels nice and i'm loving the short shifter, but the car shuddered and vibrated VERY badly under heavy acceleration in 1st and 2nd gear.

Did some reading that convinced me to buy a new driveshaft, the rear U-joint was pretty stiff. Picked up a rebuilt one, freshly balanced with (another) new CSB. Also picked up some new motor mounts.

Back on the lift. Removed vibration dampener and installed new driveshaft. Installed new motor mounts.

At this point I was Hoping that the problem would be gone and i'd get to feel how smooth the car drove with the new driveshaft.... No.

The shuddering/vibration is less severe, and is now happening at lower RPMs in 1st gear under any load, and 5k+ in 2nd gear under moderate to heavy load.

I'm thinking that maybe if the rebuilt driveshaft was balanced with the vibration dampener on, that taking it off maybe messed up the balance?


So..

New tranny
New clutch
New flywheel
New tranny mount
New motor mounts
New driveshaft
New CSB
New Guibo

Taking it back tomorrow to remove and rebalance the driveshaft.

Keeping in mind that the car did not do this before the new tranny/shifter/clutch/mounts/driveshaft were installed, can anyone offer any other suggestions before I pay to have it rebalanced?

[jlevie]

Drive shaft speed is too low in 1st or 2nd for balance to be an issue. What you describe sounds more like a bad drive shaft or possibly a problem with the differential mount or half shafts.

[Inline Sex]

Drive shaft speed is too low in 1st or 2nd for balance to be an issue. What you describe sounds more like a bad drive shaft or possibly a problem with the differential mount or half shafts.

Ok i'll pick up a diff mount too. If it were the half shafts why would I just now be feeling it after replacing everything?

[s_ribs]

Curious to hear what you find out.

[Wh33lhop]

Can you semi-locate the vibration? e.g. Right now I've got a bad guibo and it "feels" like the vibration is coming from directly underneath me when I get on it.

[StereoInstaller1]

I have the same issue...maybe not as severe, but it pisses me off enoughto not drive the car.

I was reading the factory service manual, it kept talking about the "Drivetrain Alignment", as in the perpendicularity of the engine/tranny to the rear end, and how BMW actually made a specific tool to test/meassure/fix all that crap, which is why the tranny crossbrace is so adjustable.

Just saying....

[Inline Sex]

Got the "new" driveshaft rebalanced, the guy said that it was unbalanced in the rear. Put it in the car and I'm pretty sure it is exactly the same. 1st gear from about 2500-4000 under any acceleration, and 2nd gear 5000-Red only under heavy acceleration. This time I made sure the CSB was preloaded, I pushed the bottom of it forward a little bit while the bolts were loose, then we bolted it up, which I THINK is the proper method. I also got the tires balanced cause they needed it anyway.

So assuming it's not the tires, tranny, clutch, flex disk/guibo, driveshaft, csb, diff (new-ish) or the diff mount (checked, it's fine)..

That only leaves the drive axles. From what I've read though, this doesn't seem to be a symptom of bad drive axles/CV joints, I could be wrong..

Additionally, I forgot until now, but my mechanic used E36 325i tranny mounts, he said he likes to use them because they're more sturdy.. or something. I just went with it, I don't think they are any taller so I don't think that would cause an issue, but I could be wrong.. any thoughts?

I'll update when I figure it out, too many vibration threads with no end result.

Until then, any more suggestions?

Thanks!

[Inline Sex]

Can you semi-locate the vibration? e.g. Right now I've got a bad guibo and it "feels" like the vibration is coming from directly underneath me when I get on it.

It's hard to tell, I think it feels like it's coming more from the rear. I don't feel it in the wheel, the clutch or the shifter. A brand new guibo is on there and I don't think they can be installed improperly.. so I doubt it's that. Does yours only do it in lower gears?

I have the same issue...maybe not as severe, but it pisses me off enoughto not drive the car.

I was reading the factory service manual, it kept talking about the "Drivetrain Alignment", as in the perpendicularity of the engine/tranny to the rear end, and how BMW actually made a specific tool to test/meassure/fix all that crap, which is why the tranny crossbrace is so adjustable.

Just saying....

Yeah I was just reading something similar in the bentley, about using shims to test the "driveshaft deflection"?

That's the only thing that makes me wonder about the tranny mount. It says in the bentley that if a driveshaft is vertically misaligned, shims can be placed between the CSB and the body. so if this e36 mount is either taller or shorter.. that could throw off driveshaft alignment. I haven't been able to find any measurements to compare the two mounts, I guess you can't find EVERYTHING on the internet. :down:

[Wh33lhop]

It's hard to tell, I think it feels like it's coming more from the rear. I don't feel it in the wheel, the clutch or the shifter. A brand new guibo is on there and I don't think they can be installed improperly.. so I doubt it's that. Does yours only do it in lower gears?

I had a bad CSB which I just replaced, that did it sort of all over, but the guibo really only acts up towards the top of first/bottom of second, otherwise it's fine.

If you really pay attention, you may be able to locate it. Once I realized where the vibration was coming from, it was pretty easy to diagnose the problem (had another problem where the dead CSB caused the driveshaft U joint to bang against the heat shield whenever I got on the brakes, I was pulling my hair out until I tracked it down by really listening to where it was coming from).

[dreamchasin]

bump on old thread. i have this issue if i get on it in 1st gear. or slowly climb to high RPMs in 2nd and get on it. i hope its not axles but ill be ordering a new CSB next week.

[jlevie]

A problem that occurs when the drive train is subjected to high torque loads, like accelerating in the lowest gears, will be binding drive shaft u-joints and/or a bad CSB/guibo, or a problem with the half shafts. If the problem only occurs at high speed, out of balance tires, out of balance drive shaft, or a bad guibo are possibilities.

[gp.plus]

I thought the e36 mounts were different, and the e21 trans mounts were a stiffer upgrade. Doesn't. The e36 come with a zf trans and a different crossmember? I know the e21's came with getrag boxes. Maybe your mechanic was misinformed.

[dreamchasin]

A problem that occurs when the drive train is subjected to high torque loads, like accelerating in the lowest gears, will be binding drive shaft u-joints and/or a bad CSB/guibo, or a problem with the half shafts. If the problem only occurs at high speed, out of balance tires, out of balance drive shaft, or a bad guibo are possibilities.

thanks j. my guibo is in mint condition actually. my CSB looks a little shady but it feels like it's coming from the rear end. i am hoping its not axles but i think it is. they are soooooo expensive and the ones from advance auto are shitty as hell and 70 dollars each. im going to put it on jack stands tomorrow morning and check over everything. wish me luck.

[dreamchasin]

so i was just under my car for a couple hours. my driveshaft is hitting my gas tank. i don't know how. my center support bearing is completely fine. so is my guibo.

[jlevie]

so i was just under my car for a couple hours. my driveshaft is hitting my gas tank. i don't know how. my center support bearing is completely fine. so is my guibo.

That would mean:

The tank is adrift and has dropped down.
The differential is adrift or the subframe is damaged.
The drive shaft u-joints are blown out.