question about transmission mount

My transmission mount has not dry rotted or torn but does have some play in when I put up on the t-case. My question is can a rubber transmission mount become soft and allow too much movement when it gets old? My 97 XJ has it's original mount and is now 14 years old with 200,000 miles on it.

I have been battling cracked headers for a while now (I think I just cracked number 8). I have replaced both motor mounts with stock rubber replacements from the dealership. I have also added a flex pipe to the down pipe. I also had polyurethane motor mounts on it at one point and it still cracked but the poly mounts transmitted too many engine vibs into the chassis for my taste. The vibs made every rattle and creak in the jeep go crazy when idling in traffic. So with my ADD it about drove me insane.

I thought about maybe a poly trans mount but after my previous experience explained above with poly mounts, I am worried a similar situation will happen.

Any thoughts?

Ben824 said:

My transmission mount has not dry rotted or torn but does have some play in when I put up on the t-case. My question is can a rubber transmission mount become soft and allow too much movement when it gets old? My 97 XJ has it's original mount and is now 14 years old with 200,000 miles on it.

Click to expand...

Yes.... at 200K it's more then definately "loose" and allowing for a fair amount of play.

I have been battling cracked headers for a while now (I think I just cracked number 8). I have replaced both motor mounts with stock rubber replacements from the dealership. I have also added a flex pipe to the down pipe. I also had polyurethane motor mounts on it at one point and it still cracked but the poly mounts transmitted too many engine vibs into the chassis for my taste. The vibs made every rattle and creak in the jeep go crazy when idling in traffic. So with my ADD it about drove me insane.

Click to expand...

I believe that the rule of a thumb is to replace all three at the same time as one being older/more worn then the others will allow for more play and that can result in cracked header. I have MORE mounts and found them to be soft enough not to be annoying but yet firm enough to disallow play.

I thought about maybe a poly trans mount but after my previous experience explained above with poly mounts, I am worried a similar situation will happen.

Click to expand...

I'd stay away from poly mounts on the transmission. I thing they are too stiff resulting in other issues.

Thank you for the advice! The new motor mounts are not too old and I checked the other day to see if they were allowing too much movement in the engine and they didn't seem to be so I will change out that transmission mount and hope for the best.

I wish I could afford the MORE mounts or the brown dog mounts as I have heard good things but money is tight and I need new axle u-joints and new ball joints too.

Stay away from the Rusty's tranny mount. I bought it to replace my worn stock mount after 100k and couldn't get it to fit (they refunded it). Ended up just replacing it with a rubber OEM mount and glad I did. MORE motor mounts were a great upgrade for me as well.