diff issues....thoughts from the pro's?
 

Alright,...was always told two heads are better then one....etc etc. Well... i'm trying to get some other ideas,..on my current situation,...of what I can do to get myself out of a jam. Think I know the answer but,..maybe some of you can think outside the box that my mind is currently stuck in.


Car: 00 FRC manual, twin turbo, 787rwhp 696 ft-lbs on 11psi and stock block internals. Various mods.

Coilover suspension and 335's with mini tubs.

Here's the story. We(i'm a gm technician) just installed a hardened output shaft in my stock 120,000 mile diff. Some metal came out on the magnet. Also found my clutch pack cone washer, had snapped in half, and clutch packs were all worn on left side.

We cleaned everything, installed NEW clutch packs, and hardened shaft,..with new fluid and GM additive. Went together easy. I drove it under mild load here and there but, it's been wet out so, I couldn't really romp on it. Then, last week, it was dry out so I ..in 1st gear, got on it.....everything is fine,...tires spinning.....go to hit second gear, quickly...and BANNNNGGGGGCLANK. Done.

I happened to be right by my dealership, and nursed it inside.

Dissasembled it. Found the right side bearing is toast....as a result, the debree, took out my ring and pinnion gears, as well as my right side cover.

Here is the good news.

My old gm teacher, had a spare 2,73 diff, that was given to him by a former student. It was taken apart, and nobody knew anything about the history of THAT diff.

So, he gave it to me. I have decided to try and use the 2.72 diff, with my output shaft. It SEEMS, although it could just be dry, that the PINION bearing COULD be damaged or worn in the 2.73. So, I priced out new 2000 clutch packs, new carrier bolts,...and the new pinion bearing setup, which is part #88984478...which is actually called the cage, and is MINUS the gear,...which I don't need.

The price i'm looking for everything is between 580.00 and 650.00 bucks to replace the:

cage(list price 720)(pinion BEARING KIT) but I can get for like 360ish
clutch pack kit
and bolts

all for $580-$650. Thats with me doing all the labor(which sucks).

That'll give me a 2.73 rear gear on my manual setup.

Is there a better Idea that you guys have,...a better way to spend the money? My car is sitting on a rack behind me...waiting.

I appreciate any logical insight.

Also...any better clutch pack idea's?
Thanks again.

2.73 seems a bit low for a standard car. Maybe look into something like this?

http://www.lgmotorsports.com/catalog...oducts_id=1409

$1,695.99

That looks to be wayyyy out of the price range, unless someone hit the lotto and forgot to tell me...

Those gears will not make you very happy... Might be able to pull some 200+ mph runs (-:

Pull out the ole Credit Card and get the one from LG....

OR search the local junk yard... I dont think its worth the $650 to rebuild a 2:73 gear set up

I would go with @ least a 3.15 And i think you will be pleasantly surprised how those turbos like to be under a load.

with your power and those gears, you could do 220mph..lol seriously

but, you will not like them, and it will be a slug on the shifts. With that kind of power, you really need to have a bulletproof diff. i would take the case you have now, and go to DTE and have it built with all the good stuff. They use custom stuff that insures it can handle a good beating. They are out of Indiana. Its going to cost in teh 2k range, but is 2k really that much when you are gonna rebuild it a few times at 500-700 bucks a pop?

i would also go back to a 3.42 gear. nothing lower.

I have a built 4.10 in my car now

but, you will not like them, and it will be a slug on the shifts.
i would also go back to a 3.42 gear. nothing lower.

I have a built 4.10 in my car now[/QUOTE]

I disagree when your talking about 700ftlbs of torque and Turbos that like to be under load.. I don't think hes looking to bolt on slicks and bang gears down the quarter.. 4.10 is fine with a n/a setup but when you start making serious h/p in a limited rpm range its unpractical ..Yes in a perfect world we could all afford 2-3k differentials with all the goodies.. I know I cant.. I know allot of guys that don't drag race IE: (slick up and try getting it out of the hole) with 700 800 hp that have stock differentials that have lived for years and thousands of miles!! And yes they are on borrowed time but it can be done.. My old c4 had a stock dana 44 with 3.08, stock half shafts and i was slicked up. ran 9.38 @156 with a 1.38 60. and i never broke the rear or a half shaft...
Totally different animals but you see what I'm saying

Your SOL on clutch packs more or less. The only upgraded ones are the DTE ones if I recall. They last quite a while under typical use however.
There is bound to be a used vette diff somewhere. Slap a cooling system on there as a charm to ward off the heat demon.



I chunked mine though as the limited slips get very toasty when you got wide meats on them with some torque.

Yeah just from reading some of his posts i can assume he drives like a lunatic lol Hes definitely going to have to build up whatever he puts in there

Damn J, too bad I didn't have my old 3.42 rear anymore. Only had about 38k on her.

As far as built stuff goes, DTE is the place. A bit on the pricey side but my stg III has had ZERO problems, and you know how I drive on the X way. I'll let you know how she does on the way home with the extra torque from my new 402. Good luck.

lol

he wanted options, so i threw that in there. :nod:

RPM Transmission in Ind can get u a new setup around $1000 + shipping

Check out: Certified Auto Recycling

too bookoo

werd....and no I didn't...otherwise you'd be driving a new ride or your ride would be a little different... :D

I just don't have that kind of money man....and i'm hoping that IF I do o with the 2.73,....i'm hoping quick shifting makes up for any loss of rpm's i between shifts. Powershifting 101 :D

I disagree when your talking about 700ftlbs of torque and Turbos that like to be under load.. I don't think hes looking to bolt on slicks and bang gears down the quarter.. 4.10 is fine with a n/a setup but when you start making serious h/p in a limited rpm range its unpractical ..Yes in a perfect world we could all afford 2-3k differentials with all the goodies.. I know I cant.. I know allot of guys that don't drag race IE: (slick up and try getting it out of the hole) with 700 800 hp that have stock differentials that have lived for years and thousands of miles!! And yes they are on borrowed time but it can be done.. My old c4 had a stock dana 44 with 3.08, stock half shafts and i was slicked up. ran 9.38 @156 with a 1.38 60. and i never broke the rear or a half shaft...
Totally different animals but you see what I'm saying[/QUOTE]

You read my mind hommie :D

Very good idea. I've been wanting to do ALOT of cooler mods to the car,...starting with the diff. It's something needed, exactly how you say. I'm still waiting on the phone call about the spare diff.

:bang:

I need to research and see how much the replacement clutch packs are now.

I think the highway suggested cruising speed should be about 110-120mph, for "certain class cars".... .....

I'm completely normal.

:burn:

true. My cousin...has gone through 3 or 4 DTE diff's.... couple of stage threes...and he is on his SECOND stage 5. Where afriad to drag race that car anymore....cause it's getting stupid(moneywise). If I had the cash...i'd buy one but,..it's just too much right now. I'd rather invest that money in a ZR1 trans(or a built trans) with diff.

and thank you for that...

Still,..for me right now, alotof money BUT.....thats the best news yet. I'll look for there site. Are they a forum sponsor?...I know they are on one of these forums. I think it's here...:confused:

alright, i'll do that.