Problem with posi.. Chevy Cant fix..
 

I have an 05 (A4) that I drag race quite often, Last time at the track when I did a burn out only the right wheel spun, I backed up into the water again and did a 2nd burn out an all was OK...

I went to my local Chevy dealership today to get a price on rebuilding the "Posi" unit with new clutches etc.. & whatever else it might need...

The service Mgr. checked his book & told me it should be about a 6 hr job, But they couldn't do it because Vetts from 2000 up they need a special tool ????? And they did not have it..

I'm going to check with another dealership that is not too far and see what they say...

Any suggestions would be appreciated...

Jpee, Julio can do it, also i had that problem, so i put royal purple in, it had the additive in it all ready, plus i put another tube of additive and it has been working great 2 years later, also do figure 8s at the track and do your burnout closer to the water, and hit it quickly and fast to burnout rpm:thumbs:

I already have a call into "CARTEK" "I TRUST THEM" to do it right.. I know about the burnout I hold the break hard, then push the LineLock button, & Hit the gas Hard & Quick..

But you may be right I may have pulled too far forward after going through the water.. I'll start my burn out at the end of the wet part of the water box...

I just changed the rear end with GM fluid & GM additive... I'll try Royal Purple before I go to our next race (June 22) & do the figure 8's (I did that with the GM oil and additive...

PS the MT are GREAT 6 runs all 1.623 - 1.640 60' times....

I lost to a 9 sec Camaro & I lost on a dumb mistake.. I dialed 11.93 & I had a .019 light, got on the binders at the 1000' but was "lackadaisical" and still broke out by .011 and took .068 MOV ... :(

I should have jumped HARD on the breaks....I guess I'm proof you can get OLD ans still learn :)

Come on JPEE, dumb it down a bit, i quit school. i had to look lackadaisical up. and i know i will never use it in another conversation.:lol:

Sorry :( I just got carried away.... LOL

Send it to http://rktperformance.com/

Rick is a rear expert, he can fix it, but the '05 has a weak rear. Most guys I know who have '05's would upgrade to a later year because of the stronger housing.

I had this exact problem when I used Royal Purple fluid in both my c5 and my c6.

In each case I replaced the Royal Purple with factory spec fill and it cured the problem. Personally I think the Royal Purple was too slippery and wouldn't let the clutches work properly...I might be all wet but dem's the facts, factory fill cured my issues.

I see that you just put in factory spec fluid...did you use the right amount of friction modifier? And did you use synthetic fluid? I'm not sure off the top of my head but I don't think it needs friction modifier? Maybe someone smarter than me can chime in on that one.

many posts on what the modifier actually does. in my case i was peg legging burnouts far to many times, starting closer to the water helped, but still got the occasional peg leg. everyone said need new clutch packs, so i decided to change, got the gear oil with the additive plus i bought 2 other tubes, i put 1 in and did the figure 8s drove about 50 miles, put the car in the garage a few days, took it out and guess what? it fishtailed on the start, at every start driving around, passing it fishtailed like it use to do:yesnod: so i stopped and did a couple burnouts and left to black marks:hurray: went to the track and never had another peg leg, if it did. as a last resort i was going to do the old brake fluid mod, last time i did that on a ford it swelled the clutches like a spool:woohoo:

:thumbs:

For sure in the old days, posi additive was whale oil! Environmentalists got a little upset about killing whales so now we have another synthetic product I believe.

My understanding is the additive keeps the posi clutches from chattering, thus, they make the fluid more slippery.

I know that is exactly the opposite of what you found to work, and you are not the first one I've heard of that fixed a broken posi with extra additive.

I've also heard of folks fixing a slipping automatic tranny with a little brake fluid...:eek: It works for a while:toetap:

Jpee because it's a pain to swap the fluid in our cars, if I was you, before I spent any more money, I'd buy another bottle of additive and throw it in. You don't have much to lose and it's easy to try.

:iagree: I'm FOR SURE going to do as you suggest.. I'll add a tube of additive before I do/try anything else... & do a few fugue 8's .. see if that helps..

I afraid to ask what it would cost to replace the clutch pack in my rear end...:eek:

:iagree:Joe i tried it in a trans and it didnt work it must have been to far gone, in the 9" ford it was a 1956 i put in the 1973 grande with a c6 trans and 68 tbird 429 it ran 10.98 consistently in 1981 and i never had another problem, it was a street car, my only car:yesnod:

jpee the new old diff fluid that GM recommends now already has the additive in it and no need to mix.everyone seems to have better luck with it. may save you the price of a rebuild. Dan

Thats what I plan on doing.. adding a tube off additive and see how it works before June 22nd (my next race date) although I CAN test it in a large parking lot...

Replacing the pack is not too bad. My shop does it in house, I'm sure Cartek can as well.

I'm nearly positive you won't need to.

Thanks :thumbs: I'll give it a try, & see how it does next time at the track June 22nd...

The newer (than 2008) GM gear oil already has the modifier included. If you add more it'll slip, according to what I read recently. If you already added one tube to the new gear oil, that may have caused the problem you're having.

Although, if you bought the older oil (without the modifier) maybe adding an extra tube will fix it.

Either way, if you add one more tube and it still doesn't solve the problem, you'll still want to drain and start fresh again with the newer oil.

Whatever happens though jpee, do not put an excessive amount of money into that 2005 rear. That same money will be MUCH better spent towards getting a different rear (C5 conversion or a 2006+) altogether as both Dennis and Joe above ultimately did with their LeMans Blue '05s. :yesnod: Some mild clutch pack work might be cost effective enough if that all it needs, but spending a lot of money on a 2005 rear is a losing proposition, especially if you have any plans to add more power in the future.
Plus if you make the swap BEFORE your '05 rear breaks entirely, you can still sell it for some extra ca$h as well (maybe as much as $400.00?), it being a 3.15 ratio and all. :)