Axle Questions...please read.
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Joined: Apr 2001
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From: Evansville, IN.
Axle Questions...please read.
I have a 1994 4x4 F-150 that I am going to put 35”x15.50” Super Swamper SX’s on, since I’m doing that I decided to get rid of my factory Dana 44 IFS and the 8.8” rear-end. Today I picked up a 9” rear-end out of a 1977 4x2 F-150 that I plan on completely rebuilding, swapping in 4.56 gears and a posi-unit. I also got the rear driveshaft and leaf springs. My question is, will the 9” go right in place of the 8.8” or is it not possible? If it is possible what all has to be done to make it work? I know I will lose my ABS brakes on the rear-end, I figure the only thing I might have to do is relocated the leaf spring perches. If anyone has done this please let me know if it is more trouble than it’s worth. Also, what driveshaft and u-joints will I have to use? I will be using my stock Borg-Warner transfer case. Should I use my 1994 factory driveshaft with a different u-joint on the axle end; the 1977 driveshaft with a different u-joint on the transfer case end, or should I get one made? I would appreciate any help that will save me some time. Thanks.
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Joined: Jul 2000
Posts: 541
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From: Indianapolis, IN USA
What You are attempting to do will work. I have seen it done before. Be aware that the driveshaft from the 8.8 will be too short for the 9".
9" pinion is located much lower than the 8.8". 8.8 is high mount pinion. 9" pinion sits lower than the actual true centerline of the complete axle assy.
Caution should be used to reset the driveshaft angularity. Acquire a liguid filled angle protractor (avail. @ Sears).
On reseting angularity, do this before measuring for new d/s.
reset protractor to zero & turn diff. yoke (ear) to 12 o clock and measure deg. angle @ diff. yoke. Do the same measurement @ rear of T/C. Next will be the tricky part. You will have to install a d/s between diff. & T/C & measure angle on that d/s tube.
Example: lets say the angle @ diff. was 3 deg. up and yoke @ T/C read -3 deg. down. You will need to know the deg. reading on the d/s tubing between these (2) points.
Take angle of tubing minus deg. angle @ diff. For convience sake, lets say you installed a d/s and tubing angle was 5 degrees in you truck. Then, 5 deg. (angle on tubing) minus 3 degrees (at diff.)= 2 degrees.
5 degree tubing angle minus 3 degrees @ trans yoke= 2 degrees. Your difference in operating angle of diff. yoke versus T/C would equal "0". This is not enough!
Ideally and this varies between who you ask, difference in operation angle of u-joints "a" versus "b" should be less than 3 degrees difference. But more than "0" degrees.
I, have seen countless nice looking & powerful creations that were a mess underneath. If You are going to spend the time & money--why not do it right, one time & not have to chase driveline problems into eternity?
Good Luck, Gearman
9" pinion is located much lower than the 8.8". 8.8 is high mount pinion. 9" pinion sits lower than the actual true centerline of the complete axle assy.
Caution should be used to reset the driveshaft angularity. Acquire a liguid filled angle protractor (avail. @ Sears).
On reseting angularity, do this before measuring for new d/s.
reset protractor to zero & turn diff. yoke (ear) to 12 o clock and measure deg. angle @ diff. yoke. Do the same measurement @ rear of T/C. Next will be the tricky part. You will have to install a d/s between diff. & T/C & measure angle on that d/s tube.
Example: lets say the angle @ diff. was 3 deg. up and yoke @ T/C read -3 deg. down. You will need to know the deg. reading on the d/s tubing between these (2) points.
Take angle of tubing minus deg. angle @ diff. For convience sake, lets say you installed a d/s and tubing angle was 5 degrees in you truck. Then, 5 deg. (angle on tubing) minus 3 degrees (at diff.)= 2 degrees.
5 degree tubing angle minus 3 degrees @ trans yoke= 2 degrees. Your difference in operating angle of diff. yoke versus T/C would equal "0". This is not enough!
Ideally and this varies between who you ask, difference in operation angle of u-joints "a" versus "b" should be less than 3 degrees difference. But more than "0" degrees.
I, have seen countless nice looking & powerful creations that were a mess underneath. If You are going to spend the time & money--why not do it right, one time & not have to chase driveline problems into eternity?
Good Luck, Gearman