Swapping gears in 9"
Thread Starter
Joined: Nov 2001
Posts: 45,326
Likes: 1,767
From: Chicago, IL
Swapping gears in 9" Any suggestions? I have pulled the center section out before, but never did a gear before. I am pulling out the 4.11 and installing a 3.50. It's a Moser 9" with 31 spline axles. The center section is a Tractech soft locker. The current 4.11's are a bit noisy but were acceptable to me.
Thoughts?
Thoughts?
9" fords are easy but you need some tools and room to work. They are nice because the shims for the pinion depth are between the pinion the pinion support and the case, not between the bearing and the pinion like a 10/12 bolt. Plus the side adjusters mean not having boxes of shims laying around. I have a pinion depth guage which cuts the time down but you can set the pinion depth with gear marking compound - just takes a few more tries.
9" fords are very forgiving as far as setup goes, I have just slammed used gears in to try at the track and never even checked pinion depth. Just used whatever pinion shim it had, took the side bearing play out, tightened the one adjuster to get ~.010 of backlash and ran it with no problems..
http://www.fnc.ch/Technik/9-Inch_rebuild.htm
read through this, if you think you can do it go for it. Worst thing that can happen is its noisy, if it has enough backlash, everything is tight and the pinion bearing preload/side gear preload is remotely close it wont break, lock up or do anything crazy. Naturally if you put it together and it howls loud enough to shake the car at 50mph you may want to find out why
9" fords are very forgiving as far as setup goes, I have just slammed used gears in to try at the track and never even checked pinion depth. Just used whatever pinion shim it had, took the side bearing play out, tightened the one adjuster to get ~.010 of backlash and ran it with no problems..
http://www.fnc.ch/Technik/9-Inch_rebuild.htm
read through this, if you think you can do it go for it. Worst thing that can happen is its noisy, if it has enough backlash, everything is tight and the pinion bearing preload/side gear preload is remotely close it wont break, lock up or do anything crazy. Naturally if you put it together and it howls loud enough to shake the car at 50mph you may want to find out why
spool is lighter, cheap and is worry free, no reason not to have one in your car. I dont think you are going to be autocrossing or taking family vacations in your car anymore so why have a weak link anywhere in the driveline. The 31 spline stuff should hold up for a while but I would feel a little safer with 35 spline. Axles are cheap so if you are going to buy a spool I would probably go with 35 spline stuff right away if you have 3.25 case and the $$. ..
