Broke the Rear Gears

[CTDCAL]

80k miles on my 2003. Drove it well, not abusively, towed alot (5k to 15k pounds - Equipment and a 30' fiver). This truck is a California SO version with the 5 speed. A few mods on the engine - exhaust, intake, box ect... . ) Runs and pulls well. Was religious about fluid changes including the diffs (appropriate synthetic redline in all places except the engine). Lost the front axle ujoints last week and while replacing them decided it was time for all fluids to be changed. Opened the rear diff cover to drain and black oil and metal everywhere. Gears broke inside the carrier for the Anti-Spin thorsen style LSD. Carrier LSD gears and housing shot, carrier bearings shot, Ring and Pinion still good.



Got to checking and found that a replacement from Dodge was way too expensive. Found two really low mile complete GM G80's from a chevy dealer mechanic for real cheap, one was prestine with less than 500 miles on it. Decided to try fitment in my axle with my ring and pinion and it fit perfectly. I am hoping that I had a fluke with the original carrier set as there is no reason it should have failed. I am also hoping that this carrier set out of the GM will perform better and last longer. I guess it does not pay to do meticulous maintainence on what is supposed to be a very heavy duty rear end. I would never have guessed that this failure would occur at such low mileage and the way I drive it, which other than towing properly within spec, is pretty easy. I use the truck, but definately don't abuse it.



Pic one is of the broken gear in the anti-spin carrier before I removed it, pic two is of the G80 installed:

 

[CTDCAL]

Here are a couple more pics that show it in a little better perspective:



I have seen alot of threads about the G80 going into our diff housing, some say it will and some say it won't. No thread has said that they have done it so here you go, it does work for sure.

 

[Huskerman]

Well, you could always do what some folks here advocate: remove your EDGE and threaten to sue Dodge for crappy parts.



Huskerman

 

[CTDCAL]

As they say, even if I was not over miles on the warranty:



"I am my own warranty station!"



Mainly because of my mild mods, but mostly because I would not trust a mechanic at my local dealer to change the oil filter, and never anything like the major mechanical components of my rig!

 

[HBarlow]

CTDCAL



You didn't report the service interval you used on the differential. How many miles between differential fluid changes?



Mine already has 174,000 miles. The owners manual requires a 15k mile service interval but I refuse to follow it. I tried 50k on one fluid change and the fluid was very black and contained lots of black powder. I changed to a 35k service interval.



I suspect that AAM and/or Dodge knows the rear ends are not as good as the DANA rear ends installed in previous Dodges but have never read any opinions or early failures until your report.



Harvey

 

[R_Painter]

CTDCAL



You didn't report the service interval you used on the differential. How many miles between differential fluid changes?



Mine already has 174,000 miles. The owners manual requires a 15k mile service interval but I refuse to follow it. I tried 50k on one fluid change and the fluid was very black and contained lots of black powder. I changed to a 35k service interval.



I suspect that AAM and/or Dodge knows the rear ends are not as good as the DANA rear ends installed in previous Dodges but have never read any opinions or early failures until your report.



Harvey

Now if you go talking to guys who sled pull they will tell you that the AAM axles and differentials are stronger that the old DANA stuff. Guess it is a matter of opinion.

 

[rbattelle]

Is the G80 what's installed on modern Duramax trucks? It's a 10. 5" ring gear, right?

Ryan

 

[CTDCAL]

When I bought the truck in Dec 2002 (it was one of the first 03's my dealership sold), within the first few days of owning it and odometer less than 200 miles, I read on TDR and DTR about the low fluid in rear diff problem. I immediately checked it and found mine was low of course (over a qt). Dealer shop could not figure out what to put in it and told me that it was supposed to be low. I topped it off with valvoline synthetic and ran it to 1200 miles. I then changed all fluids to redline; 75-90 in the diffs, MTL in the trans, and D4 ATF in the Tcase. Changed everything again at 17k and then went 20k intervals after that at 40k, 60k and now 80k. I'm real picky about this as I want this truck to last a long time. I am really surprised that I had this problem as I know many people who have the same trucks and tow as much or more than I do and never bother to even open the fill plug to check their oil since new. I will be surprised if they change it at 100k.



There were no strange noises or howling or any other indication going on prior to my discovery when I pulled the cover to change the oil. I am very thankful that it did not grenade on me with the fiver behind on a long trip far from home.



I have not seen this kind of failure discussed or mentioned anywhere, maybe just back luck for me with a bad set of carrier gears. My guru mechanic thinks the oil broke down from heat towing in the last 20k and that probably contributed. Redline is good stuff and all the other oil changes the fluid actually looked really good, so I don't know what caused this.



I do have the 11. 5 AAM Rear as that is what you got with a 5 or 6 speed in 2003 - it was a 10. 5 if you got the Auto. The Eaton G80 "Gov-Loc" carrier that I put in was from a Dmax with the allision so it also had the 11. 5 AAM in the rear. I have read some threads that said this swap could not be done as there was supposedly some difference between the pots from Dodge to GM for the same axle assembly, however I got the low mile carrier cheap and the deal was pay only if it works, so I had to try. It fit perfectly with my ring gear and the run out taken in 4 places was exactly the same as original, so at this point I got off cheap if it lasts. I know the axle tubes on the AAM axle assembly are different between the GM and Dodge, but the pot is the same.



I have read alot about the G80 not being good as far as strength and I have had several smaller versions of this diff in 1/2 ton Chebys, but this thing looks pretty stout. I won't be doing any radical sled pulling or any hard offroading, so I don't think the G80 will give me any trouble. I cleaned things up inside the axle tubes and housing pretty well and will run a flush cycle for 300 to 500 miles and change out the fluid again to make sure all is well. Now I am paranoid about this, so I will be investing in a new diff cover with a dipstick and drain and put a temp gauge on the rear diff so I can see what is happening back there as I drive.



As soon as I pull my old carrier gears out, I will post some more pics to show the failure.

 

[HBarlow]

Thanks for the additional info. I'd say you took good care of it and serviced it almost as often as the owner's manual suggests. Your service interval is better than the one I'm following. Maybe it was just a defective casting and metal fatigue.



Harvey

 

[CTDCAL]

Well, we buttoned everything back up this afternoon and took her for a spin.



Everything works well and no unusual noises so it would appear that this carrier will be fine.



Took it out in the gravel and it locks quickly and positively. Much more noticeable and quicker than the Anti-spin that was in it when it was apparently working. I get no turning clunk with this locker that I always got with the Ant-spin it came with.



I did use friction modifier with the G80 and it had no tire drag or clunking when making a tight turn on the pavement.



Now to order my Mag-Hytek diff cover and gauges from Gino's so I have it here next week when I change to new oil. I think I will change the oil either to Amsoil or Royal Purple in the 80-140w configuration and see if that keeps things cool and lubricated well.



CTDCAL

 

[Cal Brewin]

Good to hear it is working for ya... Keep us informed as to how it performs. I don't blame you for switching oil brands, it concerns me a little too as I am running Redline in mine. I did a 50/50 mix of Redline 75w90 and 75w90ns. I don't tow very heavy, travel trailer less than 7,000 lb, maybe on our trips I will try the infrared thermometer on the rearend, as I use it to keep track of my tires temps on the truck and trailer whenever we make a stop.

 

[CTDCAL]

Cal,



As far as I know, the friction modifier will not hurt the stock Anti-Spin and in all my reading it would appear that it may help in some cases. Now that I have the Gov-Loc in there, and it has clutches, I will be using friction modifier from now on. I have always ran the Redline 75-90ns since new and the oil looked good at all changes, this time was the exception. Maybe it was the time for the gears to go or the oil was bad, but I doubt the oil was bad as the front was changed with the same batch last time and it looked fine.



I think I will go up in vis weight to the extreme duty stuff for the rear diff from now on since I do alot of towing with this truck. See if that helps or at least it will give me some peace of mind.



CTDCAL

 

[d90boy]

I would be hesitant to blame the redline for the failure and cannot imagine royal purple or amsoil working any better. I did elect to put the redline 80-140 in my rear diff but used the 75-90 up front. If you really want to beef up the gear lube you might put in a quart of the heavy shockproof fluid and then top up with the 75-90.

 

[CTDCAL]

d90boy,



Yeah, I don't think I will blame the oil. Others I have spoke to suggest that I ran it pulling to hard with the 75-90 oil and it broke down from heat. I never pull WOT, but I really don't baby it either. I think the most I have ever seen EGTwise is about 750 post turbo (very briefly), not that that would tell me anything about the temp in the rear diff! Most of my towing in the last 20k miles was my 10,500# fiver (probably loaded under that weight total, but not by much). I have not pulled anything over 12k# during this cycle of diff fluid.



I am pretty set on getting a Mag Hytec cover and running 75-140 or 80-140 from now on, not sure which brand yet, may go Royal Purple since it is readily available at my local NAPA.



CTDCAL

 

[JValdez]

Did you lend it to a teenager to drive? I've seen this before but the person went around a corner and got on it while going from dirt to dry pavement. The failure looked exactly like yours. Of course i'm not saying you did this but I wouldn't blame it on an oil failure. Maybe a bad bearing to start things off????

 

[CTDCAL]

I have never seen this happen, but I can imangine the stresses involved with spinning the rears from soft to hard surfaces, particularly after looking at the way this torsen style LSD is made. This thing is engineering genius and should not have broke like it did.



Nope, I never intentionally stood on it for fun, may have mildly spun the tires a few times off road, but not abusively. Just drove it like it was meant to be driven, what it was made for, probably my fault for putting the lighter gear oil in and towing as much as I have. I still have not pulled the gear out of the carrier to photo it, but when I do I will post it up.



CTDCAL