Differential Rebuild

bozkm · 09-30-2004

Just got done get my front end rebuilt and aligned! The mechanic says the rear diff is real noisey and may need to be replaced or rebuilt. He says that most of the sound, he thinks, is coming from the pinion. He said he could replace the bearings, but if the pinion is worn, it'll still be noisey. Are there replacement parts to rebuild the whole thing? If not, is the pinion the same from a 70 diff to a 71?? I know the whole diffs are different, but didn't know if I could use specific parts from one to fix the other...since I have a 70s parts car with th older diff. So I guess money never stops going to these things

Fix one thing, find out more to spend money on!

David McCollam · 09-30-2004

The pinion bearings are about $180 from OGTS, plus a seal and crush sleeve that will be another $20 or so. This doesn't include the differential carrier seal, and the miscelleaneous bearings and seals at the axles. The early model bearings for the clip-in axles are not readily available either.

I think the bearings for the pinion are the same for all the years and models (GT/Manta). Your mechanic is correct, if the pinion/ring are worn, you'll need a new set. You might take the spare differential that you have, get him to check that and rebuild it, if need be. You could slide that up under the car and just bolt it up rather that mess with having the other one removed and put back in during the bearing replacement.

Good luck,

Dave

GTJIM · 09-30-2004

Crown wheels and pinions are always a "matched set" and lapped together before installation at the factory. So you cannot successfully just replace one or the other - especially 2nd hand ones that have further "worn" together.Swapping in a complete 1971 or later diff (that is in good condition!) is the easiest and most straight forward cure. Putting second hand parts from one diff into another would cost just about as much as installing new parts - less the cost of the parts.
However the early crown wheels AND pinion will fit - it is just the outer wheel bearings that were changed. Oh! And Isuzu Impulse gears and bearings will fit too ( but not the Isuzu outer wheel bearings ).

bozkm · 09-30-2004

The guy said it would cost about 500 - 700 bones to rebuilt my existing diff. How much do you think I could find a good used one for?? Of course, I could end up in the same boat after $1000 miles. You say that the pinion bearings, etc are available. What about the actual gears?

GTJIM · 09-30-2004

New gears are not listed by OGTS - I guess there must be some out there - somewhere. Never seen any on eBay either.
For $500 - $700 you would be able to find several complete 2nd hand diffs.
The major problem to check for is loose pinion nuts - that is what causes most gear noise in lower milage diffs.

David McCollam · 09-30-2004

Gears come up occasionally on e-bay. I'd offer you some, but all the NOS sets that I have are 3.67 and don't fit the Type A differentials. That's probably about right on parts and labor for the repair. I'd just put that spare one in there and see if it works or is noisy. You could install it yourself and not really be out anything but labor.

nobody · 09-30-2004

This was something I've been thinking about, my rear diff isn't the quietest but is not in bad shape. I have another one in great shape but would prefer to just swap out the rear gears not the whole axle. I'ts not on the gotta do list but just an idea to maybe make it better.

bozkm · 09-30-2004

Maybe I'll try the other diff..only problem is that is the older style. I just got in my order of rear polybushings, so I would have off the control arms and panhard arm anyway. I'm guessing just brake linkage, shocks, drive shaft and the torque tube cross member is all that left..and I have already removed these at one stage or another? I can also call Todd at Opels Unlimited, but I would guess shipping would be outrageous.

nobody · 09-30-2004

Or you could come get a builder housing the good axle bearings and axles less the gear set. your call you know where it is. It's a 73 and is very nice was on your right on end as you stepped into the shed. Then again I know of at least one more so let me know if I can help.

09-30-2004	#1 (permalink)
bozkm Member Join Date: May 2004 Location: Colorado Springs Posts: 207	Differential Rebuild Just got done get my front end rebuilt and aligned! The mechanic says the rear diff is real noisey and may need to be replaced or rebuilt. He says that most of the sound, he thinks, is coming from the pinion. He said he could replace the bearings, but if the pinion is worn, it'll still be noisey. Are there replacement parts to rebuild the whole thing? If not, is the pinion the same from a 70 diff to a 71?? I know the whole diffs are different, but didn't know if I could use specific parts from one to fix the other...since I have a 70s parts car with th older diff. So I guess money never stops going to these things Fix one thing, find out more to spend money on!

09-30-2004	#3 (permalink)
GTJIM Old Opeler Join Date: Jun 2003 Location: New Zealand Posts: 5,686	All or Nothing Crown wheels and pinions are always a "matched set" and lapped together before installation at the factory. So you cannot successfully just replace one or the other - especially 2nd hand ones that have further "worn" together.Swapping in a complete 1971 or later diff (that is in good condition!) is the easiest and most straight forward cure. Putting second hand parts from one diff into another would cost just about as much as installing new parts - less the cost of the parts. However the early crown wheels AND pinion will fit - it is just the outer wheel bearings that were changed. Oh! And Isuzu Impulse gears and bearings will fit too ( but not the Isuzu outer wheel bearings ). __________________ GTJim Opel Owner since last Century! Copyright © 2000-2009 J D Henry All Rights Reserved

09-30-2004	#5 (permalink)
GTJIM Old Opeler Join Date: Jun 2003 Location: New Zealand Posts: 5,686	New! New gears are not listed by OGTS - I guess there must be some out there - somewhere. Never seen any on eBay either. For $500 - $700 you would be able to find several complete 2nd hand diffs. The major problem to check for is loose pinion nuts - that is what causes most gear noise in lower milage diffs. __________________ GTJim Opel Owner since last Century! Copyright © 2000-2009 J D Henry All Rights Reserved

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09-30-2004	#2 (permalink)
David McCollam Member Join Date: Jan 2004 Location: Texas Posts: 589	The pinion bearings are about $180 from OGTS, plus a seal and crush sleeve that will be another $20 or so. This doesn't include the differential carrier seal, and the miscelleaneous bearings and seals at the axles. The early model bearings for the clip-in axles are not readily available either. I think the bearings for the pinion are the same for all the years and models (GT/Manta). Your mechanic is correct, if the pinion/ring are worn, you'll need a new set. You might take the spare differential that you have, get him to check that and rebuild it, if need be. You could slide that up under the car and just bolt it up rather that mess with having the other one removed and put back in during the bearing replacement. Good luck, Dave

09-30-2004	#4 (permalink)
bozkm Member Join Date: May 2004 Location: Colorado Springs Posts: 207	The guy said it would cost about 500 - 700 bones to rebuilt my existing diff. How much do you think I could find a good used one for?? Of course, I could end up in the same boat after $1000 miles. You say that the pinion bearings, etc are available. What about the actual gears?

09-30-2004	#6 (permalink)
David McCollam Member Join Date: Jan 2004 Location: Texas Posts: 589	Gears come up occasionally on e-bay. I'd offer you some, but all the NOS sets that I have are 3.67 and don't fit the Type A differentials. That's probably about right on parts and labor for the repair. I'd just put that spare one in there and see if it works or is noisy. You could install it yourself and not really be out anything but labor.

09-30-2004	#7 (permalink)
nobody No Access Join Date: Nov 2003 Location: in transit Posts: 3,873	This was something I've been thinking about, my rear diff isn't the quietest but is not in bad shape. I have another one in great shape but would prefer to just swap out the rear gears not the whole axle. I'ts not on the gotta do list but just an idea to maybe make it better.

09-30-2004	#8 (permalink)
bozkm Member Join Date: May 2004 Location: Colorado Springs Posts: 207	Maybe I'll try the other diff..only problem is that is the older style. I just got in my order of rear polybushings, so I would have off the control arms and panhard arm anyway. I'm guessing just brake linkage, shocks, drive shaft and the torque tube cross member is all that left..and I have already removed these at one stage or another? I can also call Todd at Opels Unlimited, but I would guess shipping would be outrageous.

09-30-2004	#9 (permalink)
nobody No Access Join Date: Nov 2003 Location: in transit Posts: 3,873	Or you could come get a builder housing the good axle bearings and axles less the gear set. your call you know where it is. It's a 73 and is very nice was on your right on end as you stepped into the shed. Then again I know of at least one more so let me know if I can help.

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