Poly MOTOR MOUNTS and TRANNY MOUNTS

[bigd65]

Has anyone used or are using both. I am thinking of putting both. I was told that the Poly Tranny mount alone is hard on the transmission case, there fore I want to install the motor and transmission mounts. Question is, do they cause ALOT of vibration. I like the stability of they poly mounts and have used them on on suspension and body. Those were stiff, but curious as if the motor and tranny mounts would cause excessive vibrations and such
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[Duncan and son]

Gary Terry "cheyenne superman" who has been doing these trucks before they were cool always advised us NOT to use the poly mounts so we have always taken his advice.
My 2 cents Paul

[bigd65]

Thanks, but any reasons why...
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[85burb]

I have poly motor mount in both of my trucks. One is not running yet but the other i had stock ones in and my 6.0 moved the rubber in them and my motor was sitting croked. It moved one up and the other down. I cant really tell a differance with just the motor mounts in the vibration area. Motor moves WAY less now tho.

[INSIDIOUS '86]

I have them. Shifter mounted to trans. No more vibration than before if anything more but smaller. The whole truck rolls and shakes more from the lumpy cam than anything Tuning the carb is easier since it don't move around so much.

Solid mounted engines can transmit an instant more tork than rubber mounts. Helps the overall et in a race and reaction time is a lil easier to dial.

The benifits aren't grand but still there.
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[INSIDIOUS '86]

I have them. Shifter mounted to trans. No more vibration than before if anything more but smaller. The whole truck rolls and shakes more from the lumpy cam than anything Tuning the carb is easier since it don't move around so much.

Solid mounted engines can transmit an instant more tork than rubber mounts. Helps the overall et in a race and reaction time is a lil easier to dial.

The benifits aren't grand but still there.
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[mooseknuckles]

.....every bushing in my truck is now poly! .....suspension, motor, trans, sway bar, and cab mounts....more efficient than 30 year old rubber.

[KQQL IT]

Poly motor trans and cab. Cant recomend for control arms unless a grease zerk is used. Mine squeaked after the 1st rain.
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[bk2life]

Originally Posted by bigd65

Has anyone used or are using both.

millions of cars on the road and not one from the factory comes with poly motor/trans mounts. that alone should tell you something.

[kalbert]

Originally Posted by bk2life

millions of cars on the road and not one from the factory comes with poly motor/trans mounts. that alone should tell you something.

It tells me that auto manufacturers build vehicles to appeal to the largest range of potential customers possible. That means the cars represent broad generalizations of performance, comfort, safety, maintenance, etc. Would your mother buy a car that required bushing lubrication every 1500 miles? I doubt it.

I used poly bushings on a Mustang II, squeaked terrible and I hated it.

Used them on my 97 K1500 upper arms, installed grease fittings and used silicone grease in them. Nary a squeak was heard.

I did not notice a significant performance change in either vehicle, other than the polly strut rod bushings on the MII prevented the front suspension from fully drooping so I changed them back to soft rubber.

EDIT: I have not used poly bushings for motor mounts, so I can't offer more than speculation. I would expect them to perform similar to rubber but with slightly more vibration and slightly less movement.

[CSGAS]

Before poly became mainstream, and racers used solid mounts, the advisable practice was to use a motor plate or a four point mounting system (like our 3-speed trucks) with the solids. That prevented the aluminum transmissions from taking on any stresses.

If you used a three point mount THEN you needed a rubber mount at the tranny because the aluminum would crack much more easily, especially in the cast ears at the tailshaft. If you had an iron trans some street racers would put a rubber mount on the compression side of the engine, maybe with a tiedown or turnbuckle, to make it more comfortable for everyday driving.

I am sure the recommendations about using poly on the trans mount developed from those recommendations. Whether it really is an issue or not should depend on what durometer the poly mounts are. You could even mix soft and hard poly mounts.

Soft poly still provides the benefit of lasting far longer than the factories expected the trucks to last.

I've learned that the only place you REALLY don't want to put poly in, is the truck arm front bushings. I haven't done it myself, but apparently even the soft poly bushings cause a bind that transfers the stress somewhere else--and I don't think any of us wants something else to get bent.

The single place where poly bushings will show the greatest benefit especially in responsiveness, is in your shock eyes/mounts. The shock can have a horribly sloppy reaction with rubber bushings. Heck, I'd even recommend rod ends or monoball inserts there. As long as you are using "interlocking" motor mounts (either with tabs or through bolts) then the next step would be the rest of the suspension bushings except the track bar. After that the motor &/or trans mounts. Then yes even harder (or solid) body mounts will help performance in the twisties by tying the frame and sheet metal together for more structure--imitating a space frame or unibody.

[bigd65]

I had the Poly bushings in the body mounts and the the suspension, including the control arms. I did like them but the suspension was considerable stiffer. I may even do it again, but kinda stuck on the motor and tranny mounts , stabilizing them more
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[gchemist]

I use polygraphite everywhere. Trans, motor, control arms and bushing. I can tell the difference right away from stock rubber. Power is put through faster and firmer through the drive train. I even upgraded my S15 Jimmy front a-arms to polygraphite. It feels better firmer around corners and curves. Any SUV should have polygraphite for control.

[bigd65]

Leave it to the CHEMIST to talk me into it. although I did not use the ploy graphite last time, I definately will this time. I will probably start with the Motor Mounts and tranny mount, and im sure sooner or later will also do the suspension and body... I did love the way my 85 handled and drove.

[Firebirdjones]

I use poly on almost everything here, (4 or 5 cars that I can think of) and no complaints here. Even my wifes 2000 SS came with factory poly mounts on the front/rear sway bars.

On my 72 blazer I put poly mounts on engine/trans/body mounts/ and the leaf spring eye's front and rear as well as sway bars. Drives like a dream.

Several others here I run poly mounts on that vary from front subframe mounts on unibody cars, to sway bars etc...

Most of them come with grease fittings now, and some are also impregnated with graphite, so squeaks aren't much of an issue anymore, and relatively easy maintanance.

Best part is that they will last the rest of my lifetime. Can't say the same for the chinese rubber you get nowadays.

[INSIDIOUS '86]

Originally Posted by bigd65

Leave it to the CHEMIST to talk me into it. although I did not use the ploy graphite last time, I definately will this time. I will probably start with the Motor Mounts and tranny mount, and im sure sooner or later will also do the suspension and body... I did love the way my 85 handled and drove.

Leaving the trans mount rubber isn't a bad idea though. The motor mounts being changed will make the biggest diff

Auto manufactures use rubber cause its cheap and gives a good ride. Same with transmissions and thier soft shift and overlap. Grandma doesn't want snappy shifts even if it means her trans last longer.
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[THE "10" SILVERADO]

Originally Posted by INSIDIOUS '86

Leaving the trans mount rubber isn't a bad idea though. The motor mounts being changed will make the biggest diff

Auto manufactures use rubber cause its cheap and gives a good ride. Same with transmissions and thier soft shift and overlap. Grandma doesn't want snappy shifts even if it means her trans last longer.
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I have heard that if you run one poly you need to run both poly. If you just run one, there would be to much flex in the system and the bellhousing could crack. Cant confirm this or not. Either way poly engine mounts will make a good difference.
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[kalbert]

Originally Posted by THE "10" SILVERADO

I have heard that if you run one poly you need to run both poly. If you just run one, there would be to much flex in the system and the bellhousing could crack. Cant confirm this or not. Either way poly engine mounts will make a good difference.
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I think that's more the case with mixing solid mounts than polyurethane and rubber. Some of the F body car guys used to run solid transmission mounts to help take the load from the torque arm, but found that by doing so it put a lot of stress on the tail housing sometimes cracking it. Probably still not a bad idea to not mix rubber and polyurethane if you can help it.

[INSIDIOUS '86]

Originally Posted by THE "10" SILVERADO

I have heard that if you run one poly you need to run both poly. If you just run one, there would be to much flex in the system and the bellhousing could crack. Cant confirm this or not. Either way poly engine mounts will make a good difference.
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I think the two motor mounts being poly should do. At that point I don't think a poly trans mount will make much difference.

Then again as I think about it the vibrations may funnel down to the tail and such. Idk all three if mine are poly. The nice thing is the trans mount is blow proof so it can't separate like the old stock ones.

I'm sure auto trans are easier on the bell housings than manual.

If I crack my trans case Ile let you guys know but so far two years no issues. And it's a lopey sucker!
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[THE "10" SILVERADO]

Originally Posted by INSIDIOUS '86

I think the two motor mounts being poly should do. At that point I don't think a poly trans mount will make much difference.

Then again as I think about it the vibrations may funnel down to the tail and such. Idk all three if mine are poly. The nice thing is the trans mount is blow proof so it can't separate like the old stock ones.

I'm sure auto trans are easier on the bell housings than manual.

If I crack my trans case Ile let you guys know but so far two years no issues. And it's a lopey sucker!
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I'd imagine if yours held up for two years there isn't a problem

[bigd65]

Well that's the first place I am starting, engine and transmission, WHEN IT WARMS UP, I live in South Texas and its COLD !!!! I hate the COLD. Guess I'm gonna have to learn Spanish, may have to relocate to Mexico, SOUTHERN MEXICO
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[Rich84]

South Texas is cold?? lol..6* this morning in Ct.

Poly cab mounts, didn't really notice a difference other then correcting the lean a little..Went with rubber on the motor and tranny...The console shakes so much it could shake a martini..But I think that that is because of the tires that the truck sat on for a few years while she was on the back burner.

[bigd65]

Well went and bought them, Autozone had the morpotr mounts and Orielys had the transmission mount. All ENERGY SUSPENSION. I FIGURE THESE ARE JUST MOUNTS, NOTHING TO SQUEEK, so these are not the Poly Graphite one. When I get to the suspension and such, you bet they will be the Poly Graphite ones. Now just gotta get the ambition to do it (won't take much coaxing. But it is cold, but then again, I do have a garage and a heat lamp. The Cowboys are out of the Playoffs soooo I guess I have time on Sunday to do it ....
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[bigd65]

OK , those that have not done this, I TOTALLY RECOMMEND IT. I put them in today, good ole south Texas, it will always get warm enough to work on the truck. Anyway, the Transmission mount was bad anyway, but with all the Poly Motor and Transmission mount, took any and all hesitation from the acceleration and drive line out. I wish I would have done these on my 85. There is ALOT more rubber in the motor mounts, kinda wonder why the factory don't use these. Gonna look at doing this to my 2010 Ford F150
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[cory d]

i may go all polyurethane soon. i need more clutch feel. rubber cab and drivline bushings have too much give and let stuff flop around