Rear Differential Seal
02-08-2012, 09:45 PM
#11
Senior Member
Its called a pinion oil seal it is very easy to change and relitively cheap to have changed you will have to refill with oil but no need to take off the cover. I would use the same type and grade of oil you just changed to. Im not an engineer and ive never played one on tv but I have built and serviced quite a few differentials and I have found Royl purple works well and if you by any chance have a limmeted slip it also contains a friction modifier
02-08-2012, 09:58 PM
#12
Just got my truck back from ford today, mine was leaking bad, went through a quart of gear oil in 3 months, it would leak out and get sprayed all on the underside and exhaust and the side of the gas tank. took me an hour to clean it off with degreaser. yes it's called a pinion seal, and Ford charged me $150 to do it. I was going to do it myself, but didn't want to screw up my rear or anything because I've heard of people having squels, vibrations, and thumps after working on it and not replacing it correctly.
02-08-2012, 10:41 PM
#13
Senior Member
I replaced the seal where the driveshaft goes into the transfer case. It still leaked. I had to get a yoke with a wider shaft. This was after installing my lift, which extended the driveshaft a little so a different area was hitting the seal.
I use 75-90 in the front and rear, but have aftermarket gears and diffs. I don't think the weight of the oil alone would cause a leak.
I use 75-90 in the front and rear, but have aftermarket gears and diffs. I don't think the weight of the oil alone would cause a leak.
02-09-2012, 09:33 AM
#14
Ford/Mazda Parts guy
I discussed this issue with a mechanic at a garage I frequent. He suspects that changing the (presumably) factor gear oil to the synthetic (Royal Purple) at 105,000 probably caused the seal to deteriorate. He claims he's seen that before. Interestingly enough, he brought up the question of the synthetic gear oil before I thought to mention it.
He further told me that the repair could be as simple as described in some of the forum articles (disconnect drive shaft, take out some bolts, pull off old seal, put in new seal) or it could be a real pain that involves removing the cover and screwing with bushings, pressure something-or-others, etc. He said sometimes it spells the end for the rear end once you get this involved in it.
His recommendation was watch the fluid level and live with it until I'm ready to open a can of worms. That isn't really the direction I like to go with my truck.
Thoughts on the synthetic theory? I'm thinking that people also tend to put in synthetic because their vehicle mileage is high and it would just be coincidence that seals would go at a higher mileage.
Thoughts on the repair? I'm considering AAMCO. I know a guy that owns one and he's an honest broker. I'm thinking they may have the knowledge to handle the problem.
He further told me that the repair could be as simple as described in some of the forum articles (disconnect drive shaft, take out some bolts, pull off old seal, put in new seal) or it could be a real pain that involves removing the cover and screwing with bushings, pressure something-or-others, etc. He said sometimes it spells the end for the rear end once you get this involved in it.
His recommendation was watch the fluid level and live with it until I'm ready to open a can of worms. That isn't really the direction I like to go with my truck.
Thoughts on the synthetic theory? I'm thinking that people also tend to put in synthetic because their vehicle mileage is high and it would just be coincidence that seals would go at a higher mileage.
Thoughts on the repair? I'm considering AAMCO. I know a guy that owns one and he's an honest broker. I'm thinking they may have the knowledge to handle the problem.
In my opinion your mechanic has no idea what he is talking about, it may be possible that the switch to a different weight gear oil may have caused the leak not the fact it is synthetic...Why you ask? Because the factory fill is synthetic, that's why. Royal Purple and Schaeffer's are 2 oils that contain a substance called
Molybdenum Disulfide
http://www.bobistheoilguy.com/moly-basics/
Pretty nice stuff if you ask me
Or it is possible that the fact you have that much mileage and seals don't hold forever is why you sprung a leak with clean fluid as the old contaminated stuff is no longer there keeping a leak plugged.
02-09-2012, 09:47 AM
#15
Update: I took my truck to the local Ford shop this morning. They agreed it was a pinion seal and quoted me $210 to fix it. They also agreed that synthetic gear oil is not a problem and the service associate told me that some rear ends come from the factory with synthetic gear oil. I've decided to go ahead and leave this one to the pros. I'll stick with fluid changes and bolt on performance.
02-09-2012, 09:50 AM
#16
Ford/Mazda Parts guy
Update: I took my truck to the local Ford shop this morning. They agreed it was a pinion seal and quoted me $210 to fix it. They also agreed that synthetic gear oil is not a problem and the service associate told me that some rear ends come from the factory with synthetic gear oil. I've decided to go ahead and leave this one to the pros. I'll stick with fluid changes and bolt on performance.
Factory fill synthetic has been since 98 to current
02-09-2012, 10:07 AM
#17
Senior Member
I used Mobil 1 75/90 in my 04 Lariat w. some friction modifyer additive. I thought the choice between 90 and 140 weight was related to operating temp?
Am I wrong?
Am I wrong?
02-09-2012, 11:40 AM
#18
Ford/Mazda Parts guy
They switched the spec in 03, reason being is the material they make the ring and pinion out of is different now. They also retro spec'd previous models to KISS so there would not be any issues
02-09-2012, 05:09 PM
#20
Seņor Member
Changing the pinion ring seal is possible in the garage, you just need a pinion flange puller.
Here's a step-by-step youtube vid.
http://www.youtube.com/embed/15zHpz6Zx8c
Here's a step-by-step youtube vid.
http://www.youtube.com/embed/15zHpz6Zx8c