12 bolt gear change questions

bowtie81

Moderator
Mar 28, 2008
5,008
0
36
sarnia, ontario canada
Hey guys
I'm planning on changing my gears in the 12 bolt over the winter. But I have never done them before and I was wondering if anyone could offer any help on proper steps to take, things to look for and re-install.
Thanks in advance
Shaun
 

454RAT

Pro Stocker
Mar 19, 2004
2,012
0
0
Summerville, SC
they are not to hard to change, but you need some tools. A bearing press and a way to check back lash. I have a spool and 4.11 gears for sale if your interested. Spool already has bearings pressed on and ring gear installed. $200
 

Ed Cannon

Pro Stocker
Jul 17, 2009
1,682
0
0
Johnson City Tn
That's a good deal^. I have changed mine several times. And dozens more over the years. You will need c clip eliminators for a full spool. Should have them anyway if you beat on it at all. Last time I changed mine I used a solid sleeve with shims instead of a crush sleeve. Well worth the money IMO. Get an install kit it has everything you need to install the ring and pinion except shims. You will need to remove the shim from your old pinion under the big bearing. Use quality gears like Richmond. Back lash on a new gear is about .008 thou. Don't run a gear with a bad pattern, once they start whining you cant make it quit with shimming, typically. Like was said you will need a dial indicator and magnetic base. I got mine at Harbor freight.
 

bowtie81

Moderator
Thread starter
Mar 28, 2008
5,008
0
36
sarnia, ontario canada
I do have a dial indicator with the magnetic base, richmond gears. I plan on getting a good kit either through summit or jegs.
What are your thoughts on using either timken or koyo bearings?
 

bracketchev1221

Dragway Regular
Apr 22, 2009
1,111
1
0
Mountville Pa
I have had good success with both Timken and Koyo bearings. Ring gear bolts are not all left hand thread. My 12 bolt was not. I think the 8.5" 10 bolts are left hand thread.
 

t01blaze

Amateur Racer
Dec 14, 2011
247
0
0
South New Jersey
bracketchev1221 said:
I have had good success with both Timken and Koyo bearings. Ring gear bolts are not all left hand thread. My 12 bolt was not. I think the 8.5" 10 bolts are left hand thread.

I think you're right. I guess I should have said to find out what the threads are before starting.
 

dragnwagon

Frequent Racer
Nov 29, 2008
605
0
0
ny
save an old pinion inner bearing and grind out a little of the center of the inner race the part that fits over the pinion gear shaft so if you have to try different shims under that bearing when you set it up it will make it easier to remove, richmond recommends starting with a .030 or .035 shim under the bearing, also you will need an inch lbs torque wrench for set up pinion preload
 

MalibuRacing.com Gear

Stickers & Shirts!!