Ok, so I've put the D300 in, and it makes the engine and tranny do a dance when I shift the Tcase. I know that the increased torque is bringing out the worst in my 6 year old motor mounts. Is rubber or poly the best solution for me? Can I assume that poly wouldn't allow as much flex, but will vibrate more? Any suggestions of a brand to go with? I ran a search, but couldn't fine exacltly what I was looking for. Thanks!

BTW - 1998 XJ with 4.0 - AW4/D300 w/ 4:1

I was using the Currie poly mounts, and there was some vibration. You'll notice it more with an auto trans. It's not to bad though. I did switch to Bombproof rubber mounts though. I don't have a good reason for doing that. I guess I just wanted to try them.

Originally posted by 4x4 Pete
I was using the Currie poly mounts, and there was some vibration. You'll notice it more with an auto trans. It's not to bad though. I did switch to Bombproof rubber mounts though. I don't have a good reason for doing that. I guess I just wanted to try them.

So do the rubber ones cut down on the vibes significantly?

I'd say it's between the Currie mounts, and the stock mounts. I'm guessing it's a harder rubber than the stock mount.

Not to hijack the thread but if you have poly motor mounts (MORE Boomproof) should the xfercase mount be a poly mount also or can it be rubber?

rubber mounts will absorb the vibes better than poly, however poly will be more durable and last longer.

Currie mounts are the most affordable for poly's
but if I had known just how much vib I'd get I would have replaced my old mounts with OEM rubber.

Originally posted by 1978CJ5er
Not to hijack the thread but if you have poly motor mounts (MORE Boomproof) should the xfercase mount be a poly mount also or can it be rubber?

MORE BombProofs for an XJ 4.0l aren't poly. They use LCA rubber bushings and are rebuildable.

They're stiffer than stock, and will loosen up a little after a month or so. Vibes only at idle.

ChiXJeff

Poly should not be that much more noticable than the hard rubber mount. Something else might be going on.

Make sure the case is not touching the crossmember or the skid plate.

I would use these to make my own
http://www.rocklogic4x4.com/products/suspension/XJBushing.JPG


www.rocklogic4x4.com

Go SOLID!

CJ

I don't like rubber mounts...........

http://www.wfo-offroad.com/carnagecorner/images/DSC01816.JPG

That's not looking good. Please tell me your hard on your equipment.

I use rusty's poly MM and surprisingly they have held up well, more vibs, but who cares, they do their job. Go poly and forget about them... Judd

Originally posted by ChiXJeff


MORE BombProofs for an XJ 4.0l aren't poly. They use LCA rubber bushings and are rebuildable.

They're stiffer than stock, and will loosen up a little after a month or so. Vibes only at idle.

ChiXJeff


Blah, yeah you're right. I thought they were poly bushings for some reason :emb4:

So the consensus is go with the MORE bombproof RUBBER mounts? I'm wanting something pretty stiff to cut down on the movement of the D300. Is poly a better solution for my application, or will the MORE's be stiff enough?

I say get the poly bushings. Its a 4x4...you guys are complaining about engine vibes?

before doing anything, check the torque arm and stud on your transmission mount.

for some reason, there is some slop built into this. also, i have broken 2 studs with stock 258's...so check it out.


this is my solution to the funky stud: get 2 new rubber or poly isolator bushings, a stack of 1/2" grade 2 flat washers (larger o.d. than grade 5), a few 1/2" grade 5 or 8 flat washers, and a 1/2" grade 5 or 8 bolt and nylon lock nut. drill out the hole in your skidplate to 1/2". measure from the top side of the skidplate, to above where the top of the upper bushing would be and add a little to that to get to a common bolt length...i think 3" is close. stick the lower bushing under the torque arm and place a stack of the grade 2 washers under it to hold it snugly against the bottom of the torque arm. slide the bolt up thru them, thru the torque arm, and place the upper bushing on it with another washer and the lock nut. i prefer the bushings to hold the torque arm firmly. sometimes its necessary to use a utility knife and trim the bushing a bit so that when compressed it will be against the torque arm. tighten the nut and bolt until the bushings are slightly squished, and you are ready to go.

this can be done on both CJ's and YJ's. it really keeps the tranny shifter from flopping around when driving and i think it helps save motor mounts. i too thought i had a broken motor mount when i found i had a broken torque arm stud.

matt

Its no secret that poly out performs rubber in almost every catagory. Poly is also 2 times more expensive. I am working on a poly line as I type this and i can tell you that poly is very cool, you can mold it as hard as aluminum or as soft as gum. I willl never go back to rubber and will never run a solid mount again. Go poly and forget about the cracking rubber issue

So who makes a quality Poly mount? Daystar? I found one on Rusty's site, but am a little leary about the quality of anything coming from Rustys. Anyone have experience with these?

Originally posted by TexasBlake
I don't like rubber mounts...........


That is what my old OEM style mounts always did. The rubber bushing would just simply wear out and leave the bolt flopping around. I went through three sets of them within two years.

I now run the MORE Bombproofs with poly bushings, and a Daystar poly tranny mount. With three+ years on this set up, I do not notice any vibrations from the drivetrain. Maybe I just got used to it. Maybe they 'broke in,' I really don't know. All I know now is that I have no problems with engine mounting issues.;)

after pushing my fan into radiator a couple of times with worn OEM rubber mounts, i ended up with Daystar poly mounts. They were roughly 1/2 the price of the MORE bushings. Yes, I have picked up some more vibes, but with a gear driven atlas sandwiched against the floor and SX's, I figured a stereo mod would fix all that. I now know that my engine will stay put when I am all flexed up.

I also use an OEM rubber tranny mount so there is a little give to take the stress off the drivetrain.

SeanP

SeanP - Looks like I'll be trying a set of those Daystar poly mounts. Don't think that I'll notice in more vibes in mine either :) Thanks for the suggestions guys.

how bout the 2.5 I'v heard the vibes are horrible

any1 have any experience

95 yj 2.5 ax5/231 8.8/30 35 ssr

poly means vibs get -Jess:D

Originally posted by MountaineerMac
So who makes a quality Poly mount? Daystar? I found one on Rusty's site, but am a little leary about the quality of anything coming from Rustys. Anyone have experience with these?


I'm using the rusty's mounts. I've had them for about 11/2 years now. So far they have held up great. Other things I've bought from him have been complete junk, ie. tow hook brackets, bu these mounts seem pretty solid, my .02 Judd

Originally posted by 4x4 Pete
That's not looking good. Please tell me your hard on your equipment.

That is what happens when you do about a 5 foot sand dune jump. The motor kinda "fell off" after that, blew the oil filter up against the frame, bent my shackle against my frane, shattered the little bracket that goes from the mount to the block on the 2.5L, my head slammed against the windshield and shattered it. It was really cool.

I replaced it with a lifetime warranty rubber one from CarQuest, a year later it's worn out. If I make another one, I'll just use poly wrangler leaf spring bushings and make my own. I don't care how much it vibrates, I hate replacing shit.

why not do poly motor mounts with a rubber xfer case mount. that would cause the minimum stress on the driveline. That's what I'm going for when I do my swap.

Originally posted by TexasBlake


That is what happens when you do about a 5 foot sand dune jump. The motor kinda "fell off" after that, blew the oil filter up against the frame, bent my shackle against my frane, shattered the little bracket that goes from the mount to the block on the 2.5L, my head slammed against the windshield and shattered it. It was really cool.

I replaced it with a lifetime warranty rubber one from CarQuest, a year later it's worn out. If I make another one, I'll just use poly wrangler leaf spring bushings and make my own. I don't care how much it vibrates, I hate replacing shit.

At least you had to smash your head to break the mount. So, if I keep my head in one piece, my mounts should be ok..;)

I'll keep my Currie poly mounts in case the Bombproof mounts break. I'm a hardass, and need to find out the hard way.

Originally posted by gipper
why not do poly motor mounts with a rubber xfer case mount. that would cause the minimum stress on the driveline. That's what I'm going for when I do my swap.

Well, the Jeep mounts are designed like an isoselese triangle. If you have the two on one side poly and the one on the end rubber, it would put lots of stress on the rubber and cause breakage.

However, I have had beter luck with rubbre tranny mounts because they have much more material in them.