Looking to replace the LSD on my 2000 mustang GT. My question was, should I drop 500 hundred for the eaton diff, or would the 200 hundred dollar Ford racing be adequate? As far as power I can't see over 300 HP in the near future. I will be using 3.90 gears. BTW its bone stock, manual transmission. I'm only looking to replace because there is a loud roar from it, and has a bit of slack. Opinions?

 

well i think it would be a good thing to change it. howling is a good indication of a bearing about to go. you'll notice a huge difference with the 3.90s. stock you have 3.27s. you dont need a eaton diff. especially if you arent going to the track. but $200 is kinda cheap? i would just change the gears and change out the bearings while you're in there.

 

I'm looking at Americanmuscle.com and the ford racing brand is around 200. Also, what could the slack be?

 

For $200, I think he may be looking at just the gears. Just make sure you take them to a reputable shop that knows what they're doing with gears, or you'll end up with the same problems you have now.

 

The "Slack" your experiencing is probably improper backlash. Meaning the ring and pinion gear are not contacting properly.

 

http://www.americanmuscle.com/ford-r...-28spline.html

 

It sounds like you have a couple things going on here...

Moan/groan may indicate a bad bearing or two. As your LSD starts to wear away the clutches, you will get some slack in the spider gears and get that clunk. Add that to some bad bearings, and it can make it worse. If you are planning on a new set of gears anyway, here is my suggestion for parts needed to make everything all new again:

1) New gearset (your choice on ratio)
2) Ring & Pinion Install Kit w/ bearings (Ford Racing M-4210-C)
3) Trac Lock Rebuild Kit (Ford Racing M-4700-C)
4) 2 qts Royal Purple 75W90 gear oil (no need for friction modifier)

If you are not very mechanically inclined, you will want a shop to do all this work. If the new gears are not set up properly you will get gear whine and can cause extra heat in the rear end. You are looking at quite a bit of labor to do all this, so don't be surprised if you are quoted $500 or more.

There is really no reason to replace the trac-lock with a new unit, the clutch packs are rebuild-able. In fact, for a better performing track-lock, there is an alternate way to repack the clutch discs to get it to lock up better. Do a quick google search and you will find all kinds of videos and how-to articles.