Rear diff (G80) locked??????

[5LZEATR]

I'm new to the site and love it. Lots of useful info. I have a 99 2 door hoe with differential problems. It is the G80 unit limited slip, posi trac. Problem is this: drives fine going straight no noises or whining, but when you turn fairly sharp the differential is still locked like it has a spool in it. I changed the diff lube today and still doing it. After the fluid change, I drove to work (35 miles), and did about 10 figure-8's in the parking lot, no change. I used Royal Purple full synthetic after lots of research on this site and others as well. I kept getting conflicting info on which lube to use (even from the dealership). Any and all help or suggestions on what to do (or which replacement diff to buy) would be greatly appreciated. THANKS

 

[5LZEATR]

Anybody??? Please

 

[Sepiroth]

Unless the stealership hired a bunch of morons, they should know the additive to add to your rear end.

It reads to me as if the additive is missing or your posi unit is fried. If it is fried, now would be the best time to install a rear end that is of better quality than the G80, like a strange rear end.

 

[992door]

put a 14 bolt sf in it

 

[95TwinTT]

If you end up having to replace the diff, I would suggest using the "Torsen" design named after the guy that designed it.

I'm using the Moser version of it that they call the "Truetrac".

Here is some information about how it works and the Moser site that handles them. Good luck.............. :thumbsup:




http://www.moserengineering.com/Pages/Differentials/truetrac.html




http://www.autozine.org/technical_school/traction/tech_traction_4wd_2.htm

 

[5LZEATR]

Thanks for the replies. I've now accepted the fact that the diff will have to be replaced. I use this vehicle as somewhat of a daily driver that will see tow duty for the boat in the summer and 1 or 2 ATV's a couple times a month. I need a diff that will have the driveability of an OEM unit but will last longer. This truck will very rarely see any significant off-road conditions. Any reccomendations?

 

[Sepiroth]

A couple of recommendations were already made in this thread.

 

[95TwinTT]

Thanks for the replies. I've now accepted the fact that the diff will have to be replaced. I use this vehicle as somewhat of a daily driver that will see tow duty for the boat in the summer and 1 or 2 ATV's a couple times a month. I need a diff that will have the driveability of an OEM unit but will last longer. This truck will very rarely see any significant off-road conditions. Any reccomendations?

The Truetrac is smoother and stronger than OEM. No clutches to wear out. Fewer moving parts than OEM. I don't know how the cost compares with a replacement OEM diff, but the Truetrac is the best of the best.

 

[5LZEATR]

I have now decided to go with the Truetrac diff. Talked with a reputable mechanic today and he suggested the Truetrac before I mentioned it. He said he has installed approx 75 and no issues with any of them. He said he would install it for $100 but he is going to charge me $530 for the diff unit. I'm going to get the diff myself, because I can get it for considerably less, and just let this guy install it. The problem is I dont know if I have 28 or 30 spline axles?? I have a 99 2 dr 4X4 with G80 diff and 3.42 gears. Is there any way to know what axles are in it???? I ask this because there are 2 different part numbers for the Truetrac one for 28 spline and one for 30 spline.

 

[newmarketEOD]

IMO putting money into a 10 bolt isnt your best option.
As previously stated, get a lightweight 3/4 ton SF 14 bolt from your local junkyard.

 

[oneradride]

Mine did this once.. I wipped around a medium and it stuck locked in. I was so pissed I floored it in reverse. Not sure how all that differential stuff works but somehow that freed it up. Not the I’m recommending you beat the sh!t out of your truck.. but if its broke anyway.
This was over 2 years ago and I have not had any problems since.

 

[5LZEATR]

Will definitely try the reverse idea. Not really much to lose anyways. As for putting money into a 10 bolt, I use this vehicle on highway 90% of the time and was under the impression that the Truetrac would be good for this application. I have no intentions of off-roading this vehicle and the only reason I got a 4X4 is to make sure it would pull my boat out of the water. Is the Truetrac the right choice? Is the 10 bolt adequate for on road, daily driver duty or is there another weakness?

 

[95TwinTT]

These 10 bolt chev rearends have pulled millions of trailers billions of miles without problem. My guess would be yours had problems from lack of additive.

You would save a lot of money and time to just do the Truetrac and call it a deal.

I have never been a fan of junk yard parts. You rarely know what the condition is. I believe you are looking for reliability.

 

[5LZEATR]

Reliability is exactly what I'm looking for. At first, I did a little research on a junkyard replacement (complete rear) and found that they go for anywhere between $750-$1200 and that price includes the peace of mind in NOT knowing if your any better off. Gonna just go ahead with the Truetrac- IF I can figure out what spline axles I have???

 

[95TwinTT]

When you order the truetrac, they will know what axles you have. You can also find out from a GM dealer, parts department by giving them your vin #.

 

[newmarketEOD]

My apologies, used to spending my time on off road forums, I have a bad habit of assuming off road durability is needed. ha. Also sounds like the JYs around you suckk

 

[5LZEATR]

No problem. Thanks for the replies. I ordered the Truetrac and install kit yesterday. I'm confident that it will do what I want it to.