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Discussion Starter #1
Seeking help desperately,

I have acquired some vibtration ever since the transmission mount were replaced. The mounts were from IAP and they did come with the extra plate Greg Gorden mentioned that should be removed for gtv6 application. So i followed his advise and removed those plates but situation had only improved slightly.

There's still significant vibration coming from the rear left and right when the engine is revving between 2k to 3k even when the car is standing still. That made me suspect vibration is coming from the transmission mount instead of driveline related.

I am sure someone out there has similar experience but i just couldn't find a solution from the threads i had read.
 

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Discussion Starter #2
Can anyone give me a little feedback regarding your transmission mount replacement experience. Tell me your story and may be the wisdom of the crowd can get my problem solved.

Thanks in advance
 

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I replaced mine with ones from IAP. I did not remove the plates and I have no problems with vibrations. I also cross drilled and bolted them. I also replaced the front giubo and the center surround on the driveshaft. Al Mitchell modified my ceneter surround to make it stiffer. I also replaced the clutch with a lightened and balanced flywheel from Richard Jemison.
 

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first you need to establish where its coming from. 1)dip the clutch then see if it goes away. if it goes away on dipping and revving, its the transaxle/clutch assembly, if it doesnt its the driveshaft.

you simply replaced the forward transaxle mounts nothing else? If so 1) did you pull down on the shaft in anyway? did you support it whilst it was disconnected at the rear end? (easy to bend them) 2)when you seperated the rear donut from the spider, did you grease up and make sure the shaft end bearing was free, 3) when you put the shaft end shperical bearing back in, did you make sure it was perfectly centred? if its not centred or free it will vibrate. 4) did you eye ball all the bolts from the rear donut and make sure they were all the same before you re-fitted them? I weighed all mine to make sure they all weighed the same. Lastly after bolting it all back up did you run the entire drive line with all the bolts backed off (including the front yoke pinch bolt) a turn, to let everything find its natural position, before you tightened it all up again?
 

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Discussion Starter #5
Thx for the replies,

First of all i have an 85 gtv6. What i did was dropping the transmission slightly only, didn't disconnect the drive shaft at all. I replaced the two front mount and the rear round mount, but that's it. Didn't replace anything else.

The banging noise came from the rear left and right, pretty sure it's not the driveshaft or exhaust vibration because i had the car jacked up in the garage for inspection. The rear vibrates significantly while the car is revving between 2000-3000 rpm regardless of moving or not. Dipping the clutch while driving reduces rpm so the noise went away. I will try dipping while the car is sitting still to see if its a clutch aligment problem.
 

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i suspect you have damaged the drive line by failing to disconnect at the rear guibo. by lowering the transaxle without dissconecting the rear guibo, you will have thrown the vertical alignment out at least and put stress on the front and rear guibos, as well as the drive shaft itself, I suspect you have bent the spherical bearing and nub at the rear guibo.

Also you have put in new mounts so you have changed the vertical and fore/aft alignemnt. you MUST slacken all rear guibo bolts and front pinch bolt, to allow the drive line to find its new alignemnt. you simply cannot cheat on these drive lines, otherwise you get the symtoms you now have.
 

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Discussion Starter #8
Thanks mjr. My original intention for not disconnecting the drive shaft was due to the many threads i'd read from disassemble related issue. I guess my gamble had made my car worse then. I will go with your suggestions and see if replacing the offending units will improve the situation.

Thanks again
 

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I agree that dropping the transaxle far enough to replace the transmission mounts is likely to do something bad to the driveshaft. I would try to find a good used complete driveshaft. There should be plenty of them in your part of the world. If not, Larry at APE should be able to help.

Whenever I worked on a Milano driveshaft the isostatic linkage made me I wish it was a GTV6 and whenever I work on a GTV6 I wish it were a Milano with the removable cross member. Either way it is a pain.
 

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before you spend any money, try slackening off all the 3 guibo to spider bolts, and the front yolk pinch bolt, then run it for 5 minutes and do them all back up again. you may be lucky and it could just be out of alignment.
 

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FLEXIBLE gearbox mounting

Hey guys. I need an experts advice, as I have never encounterred this before.
Firstly, my car is a 1984 GTV6 2.5, and I need new front transaxle mounts. (I have already replaced the rear, about 2 months ago, and car in storage at the moment)
I went ahead and orderred a set from a "reputable"supplier in the u.k. I have just received them, and just noticed the strangest thing, the one (dunno if it is left or right), seems to be more pliable, or flexible than the other. I can literally flex the inner tab by holding it in one hand and squeesing. The other one seems really hard, can only feel the slightest flex if I apply force. Is this normal, or did my supplier friend do me in by selling me re-dressed oldies?
Any advice would be appreciated
 
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