wildman7798
Full Access Member
Finished the Sterling swap tonight - what a difference a ratio change can make. I wanted to point out a few things I found if anyone is interested or looking to do this swap.
1) Get as complete a rear diff. as you can from the 92 and up long pinion 10.25.
2) I was able to get enough adjustment from ovaling the mounting holes and adjusting the carrier bearing by moving it forward about 3/4" to make up for the slightly longer pinion on the 1994 I used.
3) Need to purchase a 1330x1350 conversion U-Joint as the long pinion uses a larger cross on the Diff. yoke.
4) Need to purchase a strap and bolt set if you don't get the set with the donor - as you go from a U-bolt type U joint yoke to the strap style.
5) I was able to use the factory overload/helper springs from the donor - only need to add the frame brackets - the holes are already in the frame.
6) You will want the hard brake lines from the donor as the fitting size to the rear wheel cylinders is larger on the long pinion diff.
7) Get the sway bar from the long pinion truck as well - the bar is re-designed to clear the housing size increase that the ABS tone ring requires.
8) If you do get a donor with helper/overloads make sure you get the u-bolts from the donor as they are longer when using the extra spring.
9) My 4.10 C6 2WD truck had the beige 19 tooth speedo drive gear - I had a used blue 16 tooth gear on the shelf and it seems to be real close. The blue gear has full length teeth - don't let the visual difference throw you off the gears are interchangeable.
10) Purchased a cheap Dorman rear diff. cover with a built in magnet as my donor rear had some water and moisture in it and want to make sure I get all the floating iron I can on the magnet.
11) I used a 80-90w Cenex oil I had laying around and put in a bottle of Ford friction modifier for the Trac loc. I will run this oil for a 1000 miles and then dump it and change to Royal Purple 85-140 full syn w/ no modifier and add an aluminum finned cover w/ drain for $90 on line.
Check over the donor diff. carefully - mine had some issues I didn't notice until I was mid-stream on the job. My long pinion yoke was broken on one of the trunion mounts. I had a spare so I got lucky. Those long pinion yokes are hard to find and in the $100 range.
That is the quick overview, I may have forgotten a few things but you get the major points. It was a pretty straight forward swap and even with just the few miles I have on it the difference is night and day. I can roll at 50 to 55 and run about 2k on the tach. I don't tow a lot and empty it still pulls through the RPM range quickly and should make a big difference in fuel economy. It will be nice to have a rig I can roll down the freeway now and not have to hover at 60 mph and get 14 mpg. I can post some of the P/n's if anyone is interested.
1) Get as complete a rear diff. as you can from the 92 and up long pinion 10.25.
2) I was able to get enough adjustment from ovaling the mounting holes and adjusting the carrier bearing by moving it forward about 3/4" to make up for the slightly longer pinion on the 1994 I used.
3) Need to purchase a 1330x1350 conversion U-Joint as the long pinion uses a larger cross on the Diff. yoke.
4) Need to purchase a strap and bolt set if you don't get the set with the donor - as you go from a U-bolt type U joint yoke to the strap style.
5) I was able to use the factory overload/helper springs from the donor - only need to add the frame brackets - the holes are already in the frame.
6) You will want the hard brake lines from the donor as the fitting size to the rear wheel cylinders is larger on the long pinion diff.
7) Get the sway bar from the long pinion truck as well - the bar is re-designed to clear the housing size increase that the ABS tone ring requires.
8) If you do get a donor with helper/overloads make sure you get the u-bolts from the donor as they are longer when using the extra spring.
9) My 4.10 C6 2WD truck had the beige 19 tooth speedo drive gear - I had a used blue 16 tooth gear on the shelf and it seems to be real close. The blue gear has full length teeth - don't let the visual difference throw you off the gears are interchangeable.
10) Purchased a cheap Dorman rear diff. cover with a built in magnet as my donor rear had some water and moisture in it and want to make sure I get all the floating iron I can on the magnet.
11) I used a 80-90w Cenex oil I had laying around and put in a bottle of Ford friction modifier for the Trac loc. I will run this oil for a 1000 miles and then dump it and change to Royal Purple 85-140 full syn w/ no modifier and add an aluminum finned cover w/ drain for $90 on line.
Check over the donor diff. carefully - mine had some issues I didn't notice until I was mid-stream on the job. My long pinion yoke was broken on one of the trunion mounts. I had a spare so I got lucky. Those long pinion yokes are hard to find and in the $100 range.
That is the quick overview, I may have forgotten a few things but you get the major points. It was a pretty straight forward swap and even with just the few miles I have on it the difference is night and day. I can roll at 50 to 55 and run about 2k on the tach. I don't tow a lot and empty it still pulls through the RPM range quickly and should make a big difference in fuel economy. It will be nice to have a rig I can roll down the freeway now and not have to hover at 60 mph and get 14 mpg. I can post some of the P/n's if anyone is interested.
