Ryan Heller
New member
does any one have a good write up on how to do this i want to get it done y i have the motor out
Thanks
Ryan
Thanks
Ryan
Rebuilding front diff
- Thread starter Ryan Heller
- Start date
big gear head
axle builder
Re: Rebuilding front diff
The 7.2 IFS on these trucks is one of the hardest differentials that I have rebuilt, and I've done several of them. There is very little access to the ring gear when trying to check the backlash and removing and installing the pinion to set the pinion depth is a pain. If you don't have to do it then I would suggest that you don't. Put new seals in it and let it be.
The 7.2 IFS on these trucks is one of the hardest differentials that I have rebuilt, and I've done several of them. There is very little access to the ring gear when trying to check the backlash and removing and installing the pinion to set the pinion depth is a pain. If you don't have to do it then I would suggest that you don't. Put new seals in it and let it be.
Don W.
Stab it and steer it
Re: Rebuilding front diff
Well here's my :2cents: , if even that:
The short version:
Take it apart, clean it, and put it back together.
The long version:
Pull the axles and the side pieces with the seals and split the case. Don't touch the ring gear bearing (backlash) adjusters. I think you'll find it sludged up pretty good. Clean everything and check the gears and bearings for abnormal wear. The bearing cups for the ring gear will prolly be slightly loose in the case. Unless there is real damage don't worry. The only repair is a new case anyway.
Mark the pinion shaft and nut then remove so you can replace the seal. This allows you to remove the pinion itself to check those bearings.
Assuming all is well which I bet it is go buy three things. Black RTV, Loctite bearing lock and a set of seals. Use the Loctite to secure the ring gear bearing cups in the case. While that's drying replace the pinion seal and install the pinion putting the nut back where it came from. Turn the pinion by hand and make sure there is NO play in the bearings and that the pinion has some drag when turned by hand. (There are specs for this but I don't have my books.) With pinion side of the case laying on its side lay the ring gear in place. Using the black RTV coat the mating surface and bolt up the other half of the case. (For me black RTV was the only thing the didn't leak.) There should be a bit of backlash. Remember, you haven't changed any adjustments. There should be no play in the ring gear bearings.
Using black RTV bolt up the steel pieces. Install new seals if you haven't already and install the axles. Get a couple of blocks and set the thing on the bench and level it. Fill with your choice of lube and let sit there for a day or two and see if it leaks anywhere, especially the case half's. No leaks? Yur done!
All this assumes bearings and gears are OK and not badly worn. If that's the case then haul the thing to a good rear-end shop and they should be able to rebuild it or there's always the junk yard....
I might have left something out but this is what I did to mine and all is well.
HTH
Well here's my :2cents: , if even that:
The short version:
Take it apart, clean it, and put it back together.
The long version:
Pull the axles and the side pieces with the seals and split the case. Don't touch the ring gear bearing (backlash) adjusters. I think you'll find it sludged up pretty good. Clean everything and check the gears and bearings for abnormal wear. The bearing cups for the ring gear will prolly be slightly loose in the case. Unless there is real damage don't worry. The only repair is a new case anyway.
Mark the pinion shaft and nut then remove so you can replace the seal. This allows you to remove the pinion itself to check those bearings.Assuming all is well which I bet it is go buy three things. Black RTV, Loctite bearing lock and a set of seals. Use the Loctite to secure the ring gear bearing cups in the case. While that's drying replace the pinion seal and install the pinion putting the nut back where it came from. Turn the pinion by hand and make sure there is NO play in the bearings and that the pinion has some drag when turned by hand. (There are specs for this but I don't have my books.) With pinion side of the case laying on its side lay the ring gear in place. Using the black RTV coat the mating surface and bolt up the other half of the case. (For me black RTV was the only thing the didn't leak.) There should be a bit of backlash. Remember, you haven't changed any adjustments. There should be no play in the ring gear bearings.
Using black RTV bolt up the steel pieces. Install new seals if you haven't already and install the axles. Get a couple of blocks and set the thing on the bench and level it. Fill with your choice of lube and let sit there for a day or two and see if it leaks anywhere, especially the case half's. No leaks? Yur done!
All this assumes bearings and gears are OK and not badly worn. If that's the case then haul the thing to a good rear-end shop and they should be able to rebuild it or there's always the junk yard....
I might have left something out but this is what I did to mine and all is well.
HTH
big gear head
axle builder
Re: Rebuilding front diff
I don't think I'd use the Locktite bearing lock in the case. That could pretty well ruin the case for future rebuilds. The bearing races are always loose in these. If they weren't then the spanners wouldn't be able to push the races to adjust the backlash and bearing preload. What I'm trying to say is that they are suppose to be loose.
I don't think I'd use the Locktite bearing lock in the case. That could pretty well ruin the case for future rebuilds. The bearing races are always loose in these. If they weren't then the spanners wouldn't be able to push the races to adjust the backlash and bearing preload. What I'm trying to say is that they are suppose to be loose.
Re: Rebuilding front diff
If you use the cast iron case you don't have to worry about using locktite
If you use the cast iron case you don't have to worry about using locktite
Don W.
Stab it and steer it
Re: Rebuilding front diff
Good point, I agree. At least in principal. On the other hand since preload and backlash are already set why not lock the cups in place? Matter of opinion I guess.
Good point, I agree. At least in principal. On the other hand since preload and backlash are already set why not lock the cups in place? Matter of opinion I guess.
Espritmike
New member
Re: Rebuilding front diff
I had to remove the diff. to get access to the oil pan (my tech didn't get the oil pump pickup secure into the pump and it fell out after 15 min of running the motor).Since it was sitting on the ground I sent it to my tranny guy yesterday to check it out. He quoted me about $400 to go through if it needs bearings. Better safe than sorry...
I had to remove the diff. to get access to the oil pan (my tech didn't get the oil pump pickup secure into the pump and it fell out after 15 min of running the motor).Since it was sitting on the ground I sent it to my tranny guy yesterday to check it out. He quoted me about $400 to go through if it needs bearings. Better safe than sorry...
