I was messing around the other day on the street trying out my "locking" rear diff, one side on the ice, other on dry pavement, and I couldn't get it to lock even once. I probably tried for a good 20 minutes, easing into the throttle, hammering on the throttle, no luck. I think it locked once.

Are these things that bad or is something broken? The one thing I did notice is if you get one wheel spinning really fast I get a goofy hum/vibration out of the rear end likes it trying to lock but doesn't want to at that kind of speed...

your locker might be worn out. Try applying a little brake on a flat surface and then the accelerator and see if it locks up. Spining your wheels fast will not lock your differential, they are designed to lock up under 25mph.

i tried all sorts of variations to get it too lock, brakes no brakes, high speed, low speed, etc... is this covered by the 5yr/100k (it is engine and driveline, correct?) or just 3yr/36k?

3/36 I am 90% sure.

just a thought but have u changed the diff oil in it latley? and if u did, did you add any limited slip or whatever its called? I know when i changed my oil i put some additive in and i could not spin both tires, even when i power braked, or put it in reverse. so i drained the oil and put new in and i can somewhat to get it to kick in now. It does not work as good as it use to, but its better.

truck only has 31k on it, but the 3 yr was up in september of 07....

have never changed the fluid, if I do completely drain it what do you recommend I put in there?

Anyone else know anything more as to whether or not this is a warranty issue?

You can throw a dodge locker in it for around $400.00 They will fit the 11.5 D-max rear or another g80 for $600.00 and change. Alot of people think the dodge rearend is a little better locker. I forget the terminology for the dodge locker but there is some info on here regarding it if you use the search tab.

if you only have 31k id take it to the dealer and make them check it out and replace whatever is wrong with it

except for my dealer blows a big one, won't take care of anything, there is another one about 40 miles away, im going to talk to them.

G80s do suck got one in my Burb for now check here for some interesting reading

http://www.dieselplace.com/forum/showthread.php?p=432312#post432312

also good read by Malibu at stuck top of this forum http://www.dieselplace.com/forum/showthread.php?t=209199

If you were going faster than 20 MPH when you tried this, the locker will NOT lock. This is a safety feature designed to prevent both tires from locking at speed and throwing you into a spin.

g80 = junk

They are junk.

Power brake it and then go back and confirm both tires spun.

They are junk.

Power brake it and then go back and confirm both tires spun.

HEY RENNAT! See you've come here from the site(Zr2usa) as well.

Mine went out about a month ago. GM put all new eveything in the rear.

except for my dealer blows a big one, won't take care of anything, there is another one about 40 miles away, im going to talk to them.


Go to the dealer and ask. When they refuse, politely ask to speak to the GM Regional Rep. The Regional Rep can authorize repairs out of warranty. You may have to wait a few weeks for the Reps next visit.

ur gonna hate me for this, double checked for the g80 designation, I don't stinkin have one!!! Man, I can't believe I didn't notice that, i'm sooo stupid.. I swear I checked before buying it... Anyone in Mi want to make me a good deal on one?

L.O.L. problem solved:D:D

gm uses syn fluid $25 per qt ,smells like grape juice,no limited slip ad. needed,these don't use clutchs like old days

ur gonna hate me for this, double checked for the g80 designation, I don't stinkin have one!!! Man, I can't believe I didn't notice that, i'm sooo stupid.. I swear I checked before buying it... Anyone in Mi want to make me a good deal on one?

Ha ha - someone's going to put you in the "Fail" thread.

Seriously, if you are in the Pontiac area or the Lansing area, you might try Schramms for a used one. They get a lot of late model nearly new stuff since they deal in only GM vehicles.

my g80 works just fine,if you can build a better one do it,or just buy the one from gm

I'm preaty sure that my truck will spin both tires going faster than 20. With the ppe all the way up spinning at 20 is no problem. Correct me if I'm wrong.

I have owned three and they all worked great for me .

I'm preaty sure that my truck will spin both tires going faster than 20. With the ppe all the way up spinning at 20 is no problem. Correct me if I'm wrong.

It'll only lock below 20, but will STAY locked until load is released. fwiw i think its a great rear end for what it was designed, just not so good for donuts:).

It'll only lock below 20, but will STAY locked until load is released. fwiw i think its a great rear end for what it was designed, just not so good for donuts:).

Mine does donuts just fine!!!:):D:D

Yeah they do donuts fine as long as you dont let off of the throttle! I found powerbraking it just enough to slip the tires then going into a donut is the best way to make sure both wheels will be working together.

Practice makes perfect!!!:D :beerchug:

yeah, i think the biggest thing is if you just mash it around a corner usually it wont lock up in time cuz you are already going to fast.

Mine locks up almost all the time turning to the left, It has sent me sideways at 50+ around corners before. It seems when going around a right hand corner it usually just brakes loose and spins one wheel until you let off of it. But it always spins bolth when sitting flat power brakeing. Alot of vehicles I have driven have been like that, I am not sure why they seem to lock up more while turning left??? My wife says I am crazy, mabe she right:D

TORSEN is the Dodge differential. Keep in mind it is not a locker. It is a TORque SENsing limited slip.

It is always 'on' though which makes certain things more gooder than the G80. On the other hand the G-80 is a true locking rear diff 50/50 bias. The torsen using gears instead of clutches is set for a 4:1 TQ Bias iirc. In real slow slippery stuff, the G80 will run rings around a TORSEN diff truck.

For everything else, I do like the TORSEN better. No funny addatives to add for the plates to engage.... and it is more durable. The trade off is that it is 'on all the time' (fishtailing anyone?) .

If I had another DMX, I would order it WITHOUT the G80, and then buy a TORSEN to stuff in there. I do like it better.