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  #1  
Old April 23rd, 2008, 17:57
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MTN4X4 MTN4X4 is offline
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true or false

i heard that if you install a poly trans mount like daystar
you also must intsall poly engine mounts, if you dont you will
crack your bell housing. true or false
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  #2  
Old April 23rd, 2008, 18:27
daniel_1988 daniel_1988 is offline
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Re: true or false

False.
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  #3  
Old April 23rd, 2008, 18:40
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Re: true or false

Not to argue, and again, I'm not 100% sure about jeeps, but I have seen automatic transmissions crack through the bellhousing before because of a new poly mount on the transmission and old, soggy, soft motor mounts. 3 cases in person, several more hear-say. Motor mounts are more important than tranny mounts, unless your tranny mount is broken in half.
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  #4  
Old April 23rd, 2008, 19:30
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Re: true or false

Not sure if that could happen in a jeep, but I definitely agree that the motor mounts are more important than the tranny mount.

If you've got poly motor mounts, I wouldn't worry too much about the tranny mount, unless it's totally f'ed.
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  #5  
Old April 24th, 2008, 16:21
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Re: true or false

it seems that if you had poly mounts on the trans, and rubber on the motor, the motor would be able to torque more than the tranny, making it a hell of a lot more likely to crack your transmission. poly in the motor would probably be fine...
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  #6  
Old April 24th, 2008, 16:24
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Re: true or false

it would make since since the energy is beng transfered further back on the tranny(the vibrations) but idk...ive never heard of it
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  #7  
Old April 24th, 2008, 16:55
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Re: true or false

not just vibrations... rev the engine with the hood open, watch it torque side to side... it moves a good deal. then add the torque of turning the wheels to that, and you really got something there!
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  #8  
Old April 24th, 2008, 17:01
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Re: true or false

from what i heard, poly has too less of give, there really really tight so when u have it in gear and give it gas theres no give at all and puts alot stress on stuff, the rubber mounts has a little more give so its not as much as stress on stuff, just my opinion....... i dont know about mixing them, but i was always told not too, never had a good reason why.... tho
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  #9  
Old April 26th, 2008, 12:10
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Re: true or false

basically... poly is hard plastic... not compare that to rubber... rubber gives quite a bit, where poly doesn't. so yes, XBoBJ you are right.
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  #10  
Old December 18th, 2008, 20:09
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Re: true or false

Sorry to bring up an old thread...really old..but i figured better than starting a new one. Anyways, i had basically no trans mount before, the rubber had basically desintigrated, so intalled a daystar poly mount. While searching to see if the vibes were normal i ran across this. my motor mounts are in good cond. but are stock rubber...so am i gonna run into problems? A cracked bellhousing would kinda ruin a good day. O and to add to the problem i have little to no $ due to the holiday season..Got the poly mount for next to nothing. Im basically just looking for reassurement. has anyone actually see it happen? and under what loads? sorry in rambling. Thnks.
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  #11  
Old December 18th, 2008, 20:36
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Re: true or false

You should not get cracks from running mixed mounts - unless the rubber mounts are on the way out anyhow.

This has a lot to do with why you should always replace all mounts if you're going to replace one - the new mount will "fail" the old mounts, and they could take other parts with them. Does that include metal bits? It's possible. Likely? Hard to say.
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  #12  
Old December 18th, 2008, 20:58
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Re: true or false

So then the question is can i go with MORE's or should i go poly? Id like to go more if possible.
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  #13  
Old December 18th, 2008, 21:06
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Re: true or false

Quote:
Originally Posted by beatassXJ View Post
So then the question is can i go with MORE's or should i go poly? Id like to go more if possible.
"Aftermarket performance" mounts (like M.O.R.E) tend to use a stiffer elastomer (synthetic rubber) than OEM or OEM/Aftermarket replacemens - so M.O.R.E. mounts should work neatly with your poly slushbox mount.
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  #14  
Old December 18th, 2008, 21:09
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Re: true or false

O.k.. 1 more question. Those mores are expensive as Sh1+..how about rusty's. i know they arent known to be as good but its a motor mount how can you scew it up? By the way thanks 5-90.
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  #15  
Old December 19th, 2008, 04:12
xcm xcm is offline
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Re: true or false

im sorry, im far from loaded, but fox 3.5 bypass shocks are 'expensive as sh1+', but more motor mounts are far from expensive.

BUT.... if theyre not in the budget, you might want to look into brown dog motor mounts, lots of people run them and are happy (i prefer my zinc coating on the m.O.R.E.'S.... , and find the american flag out of place in an engine bay, and painted parts in that area unacceptable... but whatever), the brown dogs are time tested, trail approved as well.
http://browndogindustries.com/c2572-...tormounts.aspx


...unless the rusty's are like, $15, i would go with the brown dog stuff in a budget minded build.

Last edited by xcm; December 19th, 2008 at 04:16.
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