poly trans mount coming apart!?
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
poly trans mount coming apart!?
so i was under the car this morning adjusting the exhaust and tightening collector bolts, and i noticed that my energy suspension trans mount was distorted a little on the rear driverside. kinda strange, so i unbolted it and jacked up the trans a little, and the distortion went away, hmmm. so I put it all back together and i found that the block where the threads are for the bolt that goes through the trans crossmember, is moving around when im tightening the bolt. I took the whole mount out and the block in the polyurethane is a little loose. Is the mount failing? It is about 5 years old, but has very few miles on it. Im kinda hesitant to drive the car like this, im not sure if its ready to fall apart or if this is somehow normal? anyone?
Joined: Sep 2004
Posts: 2,777
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From: Casselberry, FLA
Car: 88 V6 'bird/89TBI bird/85 T/A
Engine: 2.8/TBI/TPI
Transmission: V8 T-5/700R4 x2
Axle/Gears: 3.42 open/2.73 open/ 3.27 9 bolt
Re: poly trans mount coming apart!?
It doesn't sound normal.
That being said; are you sure that your motor mounts are in properly? I have only known poly mounts to distort when they are under an abnormal force...
That being said; are you sure that your motor mounts are in properly? I have only known poly mounts to distort when they are under an abnormal force...
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: poly trans mount coming apart!?
the motor mounts are new, poly pieces as well, and they are installed correctly. the trans mount is not squished or anything, like all the weight being on one side or anything like that, just the metal part on the bottom that the bolts screws into is coming loose. Im a little confused, wonder if thats whats causing my vibration issues.
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Joined: Mar 2007
Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
Actually I just found out my 10 year old Energy Susp mount is doing similar. mine uses just the center bolt and the threaded side where that bolt goes in isnt any longer straight acrross. Its kinda cocked and twisted a bit. Also the edges where the poly and gold metal meet is peeling back. I just picked up another from AutoZone. Im redoing my trans anyway. Since I broke 3 rubber ones in about as many months way back when, I give it props for holding up through a few trannys, the 305 and 355 and giving me 10 worry-free years. $25 in 10 years vs. $15 in less than 6 months = still a better deal! =)
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Joined: Jan 2000
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: poly trans mount coming apart!?
At least with the ES mount too, when it fails it still retains the tail of the transmission so it doesn't start banging against the floor.
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From: Northern, VA
Car: Pair of 92 Z28s
Re: poly trans mount coming apart!?
You know...i thought about that twice when i got my tranny out of the car the other day. The stud on the poly mount looked a little crooked, cause ibet it is ill have to check it again. Cheap enough to where i will just replace it while its out. Mine has been in a little over 2 years.
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Joined: Mar 2007
Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
Ill try to get a side by side of mine. Also Does anyones motor sit lower on the right?
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Moderator
Joined: Jan 2000
Posts: 20,981
Likes: 11
From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: poly trans mount coming apart!?
It should be about even, unless the clamshells are on the wrong sides.
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: poly trans mount coming apart!?
well i ordered a new mount, not going to take any chances with this beat one. Going to try a Prothane one, its built a bit differently so maybe its a little stronger. I was going to go the two bolt route this time, i figure it will help hold things together and keep the twisting to a minimum, are there any downfalls to two bolts?
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Senior Member
iTrader: (4)
Joined: Mar 2007
Posts: 860
Likes: 1
From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
My ES mount is all loose too. Like Apeiron said, at least they stay together when they're going bad. I bought a new one, and I've been too lazy to put it in yet. The loose one is still holding though, and I first noticed it being sloppy about 6 months ago. As much as they're talked up, they can still wear out apparently. But I agree that they're much better than the stock ones. The sad part is it's only behind an anemic L03 motor!
Senior Member
Joined: Jan 2004
Posts: 678
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From: Connecticut
Car: '89 Firebird Formula
Engine: 305 TBI
Transmission: T5
Re: poly trans mount coming apart!?
These kinds of threads make me laugh because everyone seems confused that an aftermarket part failed... reality check :P
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: poly trans mount coming apart!?
i think it has little to do with confusion. I asked if this is good or if it was going/gone bad.
I wasn't like "OMFG WTF is happening here this thing is like super and stuff and it broke what gives!!??"
Just a little disappointed that it did fail after so little use.
I wasn't like "OMFG WTF is happening here this thing is like super and stuff and it broke what gives!!??"
Just a little disappointed that it did fail after so little use.
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Joined: Aug 2007
Posts: 444
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From: Westfield, Mass NEC-F.org
Car: 1984 RPO "Y84" Recaro T/A
Engine: HO 305ci L69
Transmission: T-5
Axle/Gears: WS6, J65, GT4: 3:73, G80: posi
Re: poly trans mount coming apart!?
Sorry to hear that. I'm gettin ready to start replacing my suspension bits. Thanks for the warning. I'll try and avoid their stuff. I used PST's bushings and trans mount on my '72 Chevelle back in '94. Big improvement. Hows their stuff for Third Gen's?
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From: Charles County, Maryland
Car: 2000 BMW M5
Re: poly trans mount coming apart!?
My brand new Energy suspension mount does the same thing, the "plate" with the three holes in it twists when you tighten the bolt, if you only use one bolt. That is normal for this mount. Just the way it's made unfortunately. If chevy didn't try to save money by only using one bolt, instead of 2 like my nova had, we wouldn't have this problem. 2 bolts keep the plate from spinning.
Member
Joined: Aug 2007
Posts: 444
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From: Westfield, Mass NEC-F.org
Car: 1984 RPO "Y84" Recaro T/A
Engine: HO 305ci L69
Transmission: T-5
Axle/Gears: WS6, J65, GT4: 3:73, G80: posi
Re: poly trans mount coming apart!?
I'm sure the engineers had it better designed originally, GM beancounters likely. Just like our hatch pull down motor support & plastic headlight motor gears...LOL
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Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
Im not complaining though. Hell, its served many years. And $20 compared to about $15 a pop for the 3 rubber ones I replaced in a short time, its a bargain. Time served.... =) Here is a side-by-side of my old and new.
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From: Charles County, Maryland
Car: 2000 BMW M5
Re: poly trans mount coming apart!?
I hope you were using the metal plate that goes behind the mount, to compress it during install. Without that the mount will be weakened a lot. But yeah my metal block in the trans mount was "loose" from day one. Not just on my mount either, I installed one for a friend and it was exactly the same. It started wrapping up the mount a little as soon as I torqued the bolt to spec.
Re: poly trans mount coming apart!?
Yeah, really no confusion here either. I was actually amused since most everyone touts them as being the best thing since sliced bread. They're still leagues better than the stock rubber ones though. When the stock one goes bad, you get some nice dents in your tranny tunnel since it completely separates in half. If the ES mount was like that, I would've changed it the very next day. Since it's just sorta "loose", I'm just going to leave it alone until I get around to dropping my new motor and trans in. I'm also running the ES mount in my 69 Camaro with a stout motor and a 4 speed manual. Since the 69 uses 2 bolts for the trans mount instead of 1, it's still as tight as ever on that car. I just think it's funny that my 69 is easily putting out over 400 HP, compared to probably about 150 HP with my L03, not to mention it gets hammered by a manual trans, yet the L03 breaks or loosens the mounts up all the time.
I wonder if the extra, lateral stress from the torque arm on the thirdgens is another major contributing factor for the mounts getting trashed so easily. Senior Member
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Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
Yeah, I used the back plate as instructed. Also the radiused side was rearward. I never noticed it when installing it. Then again its been in and out with the different trannys and the motor swap on a few occasions.
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iTrader: (4)
Joined: Mar 2007
Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
So I was at my storage unit today and came across a forgottedn jewel. A Spohn DS Loop. Its the bolt on to the OEM crossmember one I had gotten a few years ago. So, ir utilizes the 3 holes in the aftermarket mount. In fact it has to. So, my new mount should never twist. Pretty smart design and the red powdercoated arm will look cool too =)
Senior Member
Joined: Jan 2004
Posts: 678
Likes: 0
From: Connecticut
Car: '89 Firebird Formula
Engine: 305 TBI
Transmission: T5
Re: poly trans mount coming apart!?
Maybe I'm having a brain fart, but 1 bolt, 2 bolt, 3 bolt, 14 bolts, is not going to have an effect in the direction its twisting in.. and that entire block is one peice so no matter how many bolts you put in it, if it can move inside the block, then it will.
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iTrader: (4)
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Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
They were sayinf theoretically the center bolt is causing a twist to the t-shaped metal lug inside from the tourque applied when tightening it. If 2 outter bolts are used the tightening of each forces that twisting motion against the other which has negative force on it from it being mounted to the crossmember
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Joined: Jan 2004
Posts: 678
Likes: 0
From: Connecticut
Car: '89 Firebird Formula
Engine: 305 TBI
Transmission: T5
Re: poly trans mount coming apart!?
If one believed the tightening of that bolt caused any real signifigant twising force then ok.. but I mean this is the same peice that gets ripped in half by the forces of your drivetrain (in stock rubber form)
As far as I can see, the only upside to having one of these.. which has already been pointed out, is that it wont literally tear in half, it has a safety feature to it.. mine was nice until I installed the shift-kit in the 700r4 and romped on it for the very first time.... behind the L03 no less.. it went limp after that. I actually thought I had broken something it was such a dramatic change.
The above is the only point I was trying to make earlier, I like to see someone question all these aftermarket parts, this one in particular is probably cheaper then a standard mount and offers a safety feature so why the hell not buy it.. but at the same time, I can only imagine how many people went out and bought one for no other reason then to say they have one, and had no troubles with their stock rubber mounts.. along with 12 other things they picked out from the catalog that day they didnt need, or is doing them any good..
I personally bought it just because, and it felt different until the shift-kit, then it felt just like the stock rubber mount was there.
As far as I can see, the only upside to having one of these.. which has already been pointed out, is that it wont literally tear in half, it has a safety feature to it.. mine was nice until I installed the shift-kit in the 700r4 and romped on it for the very first time.... behind the L03 no less.. it went limp after that. I actually thought I had broken something it was such a dramatic change.
I was actually amused since most everyone touts them as being the best thing since sliced bread.
I personally bought it just because, and it felt different until the shift-kit, then it felt just like the stock rubber mount was there.
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Joined: Mar 2007
Posts: 860
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From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
Yeah, I see what your saying. And agree that some do just pop up and buy something just because. I got mine after multiple rubber failures and that dreaded 'BANG' under the car on shifts. Its served me a long time and I was impressed with its performance thus far. As far as the twisting of the center, I dont think it was causing any issues. But Im pulling the trans to fix it and seemd like given its many years, looking worn and $20 bux that was well spent B4, I just went ahead and got another one. I was planning on getting one for the truck one day anyway. The S10 ones have a problem with becoming soft and colapsing down. But mies a 2003 and hasnt had issues yet.
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: poly trans mount coming apart!?
i got my new Prothane mount in today and put 2 bolts through the crossmenber instead of 1. and guess what, just about all of my vibrations went away! I can finally run the motor over 3000rpm without this horribly droning vibrating noise. Im quite happy
Re: poly trans mount coming apart!?
Just curious. Did you drill an extra hole or two in your crossmember to be able to use more than one bolt? If so, maybe I'll do the same thing when I put the new one in my car.
Thread Starter
Joined: Aug 2006
Posts: 12,803
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: poly trans mount coming apart!?
i have an aftermarket crossmember/torque arm setup and it has 3 holes
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iTrader: (4)
Joined: Mar 2007
Posts: 860
Likes: 1
From: Tallahassee, Florida
Car: '86 Trans Am and '03 S-10
Engine: 355ci and 4.3l
Transmission: 700R4 and NV3500
Axle/Gears: 7.625/3.42 Auburn and 8.5/3.08 Gov-
Re: poly trans mount coming apart!?
I just put on the Spohn DS Loop on the stock crossmember. Requires adding 2 more holes, uses 2 long bolts and requires use of the Poly mount with 3 holes. Ill get it back on when I get the tranny back in.
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