Front Differential Replacement (again)...

[KATfishing]

2008 Yukon Denali, 6.2L, AWD, 160K. Purchased vehicle at 84K with an extended warranty. Front diff went out at 118K. Warranty company approved replacement with a used diff that had a 12/12 warranty and 75K miles. That differential was inspected and maintained, and under normal driving conditions just failed at 160K. Unfortunately, this is on the heels of a transmission replacement (GM remanufactured with a 3 year/unlimited warranty). We simply couldn't afford to go with a remanufactured front diff, and opted for another used diff that has 116K and 12/12 warranty. Rear diff is still original. I am hoping this is just bad luck, but I'm wondering what you have experienced with differentials... Is this unusual? Assuming the next diff is in good shape when installed, hoping I get more miles out of it. It is a trusted local shop and they will also inspect it (put camera inside), add fresh oil and install new seals. Fingers crossed that bad luck doesn't repeat itself. Wish I could have afforded a rebuilt, but the funds weren't there so soon after the tranny replacement.

 

[Geotrash]

I’m sorry to hear about your run of bad luck. I have 105K on one Denali (2012), and 203K on another (2007). Neither have ever had a differential replaced. Keep that fluid changed on the regular is my best advice.


Sent from my iPhone using Tapatalk

 

[randeez]

2008 Yukon Denali, 6.2L, AWD, 160K. Purchased vehicle at 84K with an extended warranty. Front diff went out at 118K. Warranty company approved replacement with a used diff that had a 12/12 warranty and 75K miles. That differential was inspected and maintained, and under normal driving conditions just failed at 160K. Unfortunately, this is on the heels of a transmission replacement (GM remanufactured with a 3 year/unlimited warranty). We simply couldn't afford to go with a remanufactured front diff, and opted for another used diff that has 116K and 12/12 warranty. Rear diff is still original. I am hoping this is just bad luck, but I'm wondering what you have experienced with differentials... Is this unusual? Assuming the next diff is in good shape when installed, hoping I get more miles out of it. It is a trusted local shop and they will also inspect it (put camera inside), add fresh oil and install new seals. Fingers crossed that bad luck doesn't repeat itself. Wish I could have afforded a rebuilt, but the funds weren't there so soon after the tranny replacement.

What is failing on them that they need to be replaced?

 

[KATfishing]

What is failing on them that they need to be replaced?

Not sure. The original diff I inherited when I purchased the vehicle at 84K. Carfax showed previous diff oil changes, and I also had all fluids changed when I bought it through a dealership. At 118K metal fragments were discovered in the oil when the axle seals were continued to leak... vent was checked and clear, new OEM seals still leaked. It was under warranty and believed to be doomed, so the shop elected to pursue replacement. The used diff with 75K on it when installed was the one that just failed. The transmission was replaced in October along with a CV axle. All seemed fine at that time. Did the new transmission have too much torque for a tired front diff -- who knows, but it seems to be coincidental, oddly. Four weeks later I began hearing what I thought was either the CV axle, a cupped front tire road noise or possible wheel bearings. Took it back to shop... they also suspected something with the axle, which is under warranty, but upon inspection, led them to looking closer at the diff. They opened the pumpkin and discovered it was full of metal fragments, as if something caused an implosion. Still drove, but with an increasing noise... likely wouldn't be on the road long. So here we are. The shop is a GM preferred shop with a great reputation. They've worked on my vehicles for the past 15 years. Still, bad coincidence? Just hoping history doesn't repeat itself yet again.

 

[swathdiver]

Not sure. The original diff I inherited when I purchased the vehicle at 84K. Carfax showed previous diff oil changes, and I also had all fluids changed when I bought it through a dealership. At 118K metal fragments were discovered in the oil when the axle seals were continued to leak... vent was checked and clear, new OEM seals still leaked. It was under warranty and believed to be doomed, so the shop elected to pursue replacement. The used diff with 75K on it when installed was the one that just failed. The transmission was replaced in October along with a CV axle. All seemed fine at that time. Did the new transmission have too much torque for a tired front diff -- who knows, but it seems to be coincidental, oddly. Four weeks later I began hearing what I thought was either the CV axle, a cupped front tire road noise or possible wheel bearings. Took it back to shop... they also suspected something with the axle, which is under warranty, but upon inspection, led them to looking closer at the diff. They opened the pumpkin and discovered it was full of metal fragments, as if something caused an implosion. Still drove, but with an increasing noise... likely wouldn't be on the road long. So here we are. The shop is a GM preferred shop with a great reputation. They've worked on my vehicles for the past 15 years. Still, bad coincidence? Just hoping history doesn't repeat itself yet again.

Rebuild it if you can, do it yourself if you have the time and ability or pay to have it done but such is pricey. You can see the kits over at demandaam.com and get the labor rates and instructions from AllDataDIY.

 

[thompsoj22]

ask your mech to determine if it was ring/pinion teeth, ie chipped missing teeth,wear pattern on gears to determine proper lash on set up. or a bearing carrier/pinion. they should be able to narrow it down in an hour, you do have to split the case on the forward diff as it has no cover. the front diff carrier bearings do imo carry an extra burden with cv axles, when a new axle is installed it is possible to damage the carrier to axle interface. to much force or worse "tapping/banging" of the axle to engage it in the spline when the carrier drops out of alingment. Dont! accuse your mech of this error, instead ask did the replacement axle simply slide in? if he had issues he will know you have been doing your homework and if at fault they may cut you some slack on the cost. verify transfer case to front diff driveshaft is balanced? somthing isnt right.

 

[Geotrash]

Dont! accuse your mech of this error, instead ask did the replacement axle simply slide in? if he had issues he will know you have been doing your homework and if at fault they may cut you some slack on the cost. verify transfer case to front diff driveshaft is balanced? somthing isnt right.

Good advice, this. Also, i think it’s worth having it rebuilt by a shop that specializes in 4WD drivelines. Chances are they do more of this kind work and can replace just the parts that actually need replacing. I did have a failing diff in my ‘02 suburban and had it repaired by a specialist. $1200 out the door for bearings and seals, never had another problem.


Sent from my iPhone using Tapatalk

 

[KATfishing]

Some great advice in this thread -- I really appreciate it. Several days ago, I made the decision to proceed with having the shop install a used differential. The work was completed yesterday and it's back in my garage as of last night. All said and done, the bill was $2,075 (I know, gulp -- but combine lack of time with lack of experience, this was a calculated decision). The diff has a 12mo/12k warranty. If something is still not right, hoping it will show up before the end of the warranty. It only took a little over 2,000 miles since the transmission and axle were installed for symptoms to be heard. It drove great in those first 2,000 miles and very suddenly noise came on. I had asked the shop owner if the failure of the diff could have been related to the CV axle or transmission install in some way, and the response was nothing they could put their fingers on. I do trust the shop, but can't help but wonder if thompsoj22's points above were in play in this situation. At the time I didn't know what further to ask, but also didn't feel like there was anything to gain without really knowing the cause. I'll take it out today for a joyride, but the 5 mile ride home last night was smooth and quiet. Maybe (hopefully) all is good?

 

[thompsoj22]

you made the right decision! It is back in your garage and being driven again. Your trans/front diff issues should be behind you now, You have a warranty and didnt have to bust your knuckles doing it yourself. The cost of the trans and diff are still more responsible than buying a new DENALI for $60k and a $700 monthly payment for 6 years. Hang in there and enjoy the reliability you are restoring in your vehicle.

 

[KATfishing]

you made the right decision! It is back in your garage and being driven again. Your trans/front diff issues should be behind you now, You have a warranty and didnt have to bust your knuckles doing it yourself. The cost of the trans and diff are still more responsible than buying a new DENALI for $60k and a $700 monthly payment for 6 years. Hang in there and enjoy the reliability you are restoring in your vehicle.

This message made my day -- THANK YOU!