A few months ago I purchased a 2002 Bravada. Its a beautiful truck that was very expensive I understand when it was new. The truck has a about 154,000 miles on it. With that considered it is still in good shape. The check engine light was on but all codes pointed to the fan clutch needing replacement. After that I went though draining and refilling all the fluids. All that went well except being unable to remove the fill plug on the rear differential. I took it to a local Midas that's willing to work for just labor if you supply the parts. They welded a 3/8 extension to the fill plug and turned it out with an air wrench. With new gear oil in the rear differential with no leaks that's when I turned to the front and I wasn't so lucky. Checking the fluid I discovered it was dry. As soon as I started refilling the front differential with gear oil it fell right back in my face. I thought I had figured out the leak and had the "front drive axle inner shaft seal" (on driver side) replaced. After that I still noticed some oil (but not as much) leaking from the "pinion seal" on the back of the differential where the drive shaft comes in. I had that replaced. The differential still leaks but not as much. The oil now looks like its leaking from around where the shaft goes through the oil pan. I suspect the differential will need to be removed to fix this. At this point is where I found out that the "all wheel drive" was turned off (or just not working). I followed the advise of someone on GMTNation to test it. I placed the rear wheels in the air to see if it would drive off the jack stands - it would not. The "all wheel drive" fuse I discovered was blown. I do not care about fixing the all wheel drive. My question is this: If I don't fix the leak in the front differential (it will eventually run dry like it was when I bought it) can I continue to drive the truck without all wheel drive turned on? or in other words: Do I still need lubrication with the all wheel drive turned off? I'd be perfectly happy to leave things just as they were because it could be very expensive to get the differential sealed up. I suspect the differential would need to be pulled and rebuilt. Some advise on this would be appreciated!
2002 Bravada Front Differential Oil Leak
- Thread starter GMbo
- Start date
Sorry to hear about that.
I think the only way to continue to use the vehicle as it is (without the front diff in service) is to remove both half shafts and intermediate shaft. This will ensure a safe 2WD only experience. If you were to just pass on adding oil to the front diff things might get a bit noisy and things will seize up on you.
Even at 150K miles I would still rebuild the thing. It looks like you are going to need a rebuilt diff, disconnect, new shaft yoke and new half shafts. Seals only hold the oil in. Once that is gone you have metal to metal contact so just replacing seals won't help.
Roadie and the other members have more experience with this stuff so let's see what they say.
I think the only way to continue to use the vehicle as it is (without the front diff in service) is to remove both half shafts and intermediate shaft. This will ensure a safe 2WD only experience. If you were to just pass on adding oil to the front diff things might get a bit noisy and things will seize up on you.
Even at 150K miles I would still rebuild the thing. It looks like you are going to need a rebuilt diff, disconnect, new shaft yoke and new half shafts. Seals only hold the oil in. Once that is gone you have metal to metal contact so just replacing seals won't help.
Roadie and the other members have more experience with this stuff so let's see what they say.
Thanks - I took your advise and removed the left and right front drive axles - I left the disconnect and the intermediate shaft in however as I'm quite sure the drive shaft will not try to turn. Note: A one gallon antifreeze plastic bottle cap fits perfectly in the splined receivers where the CV axles were. I just glued them into the seal with silicon. I figured if I ever did try to fix the differential the last thing I would want in there was water or small critters ; ) I drained the differential completely of oil. The sucker can't leak now! It was worth loosing all wheel drive just so I wouldn't have to smell that 80W synthetic gear oil every time I got out of the truck . Nasty! From what I've read in some of these Drivetrain threads I'm not going to be missing a whole lot without the all wheel drive anyways. I heard most of the AWDS SDB! The last place I want to see this beautiful truck is in a f'in mud hole! Seriously if anyone has any comments about safely and are concerned about the way I disable this system please let me know. Hope I can give some ideas on more "constructive" projects in the future.
I just repaired the awd in my Bravy.. fortunately for me, it was the t-case encoder motor and nothing more sinister such as the front diff or anything internal to the t-case 
Although when I changed the gear lube in the front axle back in October, it was black, burnt and low. I have a small drip from the drain plug nylon washer because its brittle and cracked. Fine with me because it gives me a reason to change it 1 more time to get the burnt crap that was in there before out, and this time Ill replace the nylon washer.
Although when I changed the gear lube in the front axle back in October, it was black, burnt and low. I have a small drip from the drain plug nylon washer because its brittle and cracked. Fine with me because it gives me a reason to change it 1 more time to get the burnt crap that was in there before out, and this time Ill replace the nylon washer.
Thanks for the report. Years ago for a trail repair, I discovered Gatorade caps also work.GMbo said:
