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Discussion Starter · #1 ·
Hey guys, I just replaced my forward transaxle mounts and now have quite a lot of prop vibration at idle. It doesn't seem any different through the rest of the rev range.

When I put everything back together, it seemed like the rear guibo was 'stretching' a tiny bit rearwards, like as if the transaxle was sitting a couple of mm further back than before, not twisted ir mis aligned, just pulling backwards. I've not touched the rear trans mount, so I wouldnt have thought it would be able to move like that and the new mounts are exactly the same as the old.

It all went back together fine as well, no probs lining up the bolts for the crossmember, which you can see has seated back exactly where it was before.

Maybe it's just that the new mounts are transmitting that much more vibration to the floor ( the old mounts were TOAST .. the side opposite the shift mechanism was in 2 parts :eek: )

Also, I know my rear motor mount to be good so the whole thing should be in good shape

Any thoughts would be appreciated
 

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Have you read Greg Gordon's Driveshaft notes?

The driveshaft needs to settle into a position where there is no fore or aft load on the Guibos. If it's not positioned just right it can lead to vibration and worse premature Guibo failure. This is especially critical on a high powered modified car. The Guibos are strong as long as they only have to deal with rotational force. If they are being stretched in a fore or aft direction thier ability to handle a rotational load can be diminished.

Setting the fore and aft alignment is easy. When installing the driveshaft put plenty of never sieze on the spines at the front of the shaft. DO NOT tighten the pinch bolt. Finish everything else first and start the car, let it idle for a few minuets, then rev it up and down in neutral about 20 times. This will allow the Guibos to find thier neutral point and move the driveshaft into the correct postion. Now go back under the car and tighten that pinch bolt.
 

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One expert recommends running the engine with the gearbox in neutral with the Giubo bolts not fullt tightened, as well as the loose pinch bolt. Then stop the engimne and tighten the bolts.
 

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Running with the pinch bolt loose for a few good revs I buy (I do that), running with the Guibo bolts loose I don't.

Kevin
 

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Discussion Starter · #5 ·
Stop me if I'm wrong, but on my TS, I dont think I have the pinchbolt?
 

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Discussion Starter · #7 ·
Yep, that's what I thoought, any ideas on how to go about seeing to the fore / aft adjustment? Try and creep the whole gearbox forward a touch?
 

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+1000 on the pinch bolt thing. Mine rattled most of the time i had it, then i took it apart and it was even worse when i put it back together (i did run it with the pinch bolt loose, but only reved it about 5 times). A while later i loosened the pinch bolt and reved it about 30 times then tightened it up, and it was perfectly smooth.
 

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I seen how to set that up before posted. I can remember if it is set with shims or just lose pry and tighten.
I would go the the Alfetta selection try a search. and if you can't find the setup ask there,
you need to have it so it is not pulling or pushing the guibo.

Also check that the nuts and washers are matched for each set of 3. They are different weights and sizes. and some times that get mixed up. and that can cause a out of balance.
Then after everything else is sorted. you can do the last fine tune of balance with a hose clamp on the drive line, mark the drive line in quads, clamp on a hose clamp rev it in neutral notice the vibrational. rotate the hose clamp to the next quad and try again. leave it in the spot with the least amount of vibration.
might need one on each end of the drive line.
 

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Discussion Starter · #10 ·
yeah already been over to the alfetta area, joined in on a thread with similar issues, It looks like a case of moving the Transaxle forward with the crossmember loosened to take the stress off the giubo, then tighten the crossmember back up
 
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