What does a rear differential bushing kit do?

[GSX]

Hello All,

Forgive my ignorance but was wondering what the UMS Tuning 2nd Gen DSM rear differential bushing Kit might to for me aside from the seller's description:

Originally Posted by Apex Motorsports / UMS Tuning

The only way to get these from the dealer is to buy the whole rear SUBFRAME! With UMS Tuning's rear Diff Bushing Kit, you can replace worn or damaged bushings without the dealer making you spend $900! Also you will be upgrading to polyurethane instead of rubber.

My car doesn't really clunk in the rear per say, but was wondering if there would improve handling, feel, etc. Thanks for your time.

[GSX]

I was able to find this post from 2005 which describes what and where they go, but still no clue as to what factors dictate the replacement of these parts.

Originally Posted by Jtromb522

Hello friends! I NEED HELP! I have a pretty big problem and I was hoping to find any information out that I can. I have a 1997 Mitsubishi Eclipse GSX with a shot Rear Differential Bushing that's located in the subframe. There are two bushings total and they hold the two bolts that mount to the rear of the pumpkin. I called my local Mitsu parts dealership, Mistu-Graveyard and a few other places and no one carries them. My local Mitsu parts place said that it's not even in the database!!! I asked them to check if a new subframe that they have in stock had the bushings to see if it was included or a separate item altogether and it turns out that they are, in fact, a separate piece. Please shoot me any ideas of where I can find this bushing! Thanks for your help!

Hopefully one of you intelligent Handling Tech guys can answer this so we have something for the archives. Thanks again.

[90laserRSfwd]

The bushings will add a slight vibration and they could contribute to the car "feeling" like it is handling better. If your bushings are shot, which you indicated, then the car should have a "more solid feeling" if I can word it in that way, after the poly bushings are installed.

[debbie]

I have these on my car and they are ok, my bushes went bad last year and my diff followed very shortly after, so if you need new ones i would do it as soon as pos, rather than have to buy a new diff oh and to answer your question The diff kind of kicks to one side when you pull away from a standing start or when you release your clutch after changing gear, the bushes absorb this power if you like and stops the diff from moving to much and also I imagine doing damage to its self and other parts of the drive train, also by getting poly bushes or solid alloy ones the diff will not flex as much and your hard launches will be that much quicker.

[GSX]

Thanks for the explanation guys, I really appreciate it.

I got the following response to my question from UMS Tuning:

Originally Posted by Tony@UMS

It's main purpose is to have an option if your bushings are broken. The dealer only sells the entire subframe for over $900, and the only other ones on the market are solid aluminum. These are urethane bushed...still noisier than stock but better than solid metal. These bushings do nothing more than hold the rear differential in place.

Tony

But what I like is that you guys have contributed your thoughts/impressions of this product and in turn have sold me on it where before I may not have been. Big thanks to you both.