I have a 12 bolt rear end. The casting numbers are NF 3899838. I can not find any info about it. Year, Gear Ratio or anything. I want bearings, seals and gaskets for it but I don't know what to order the parts for. Please help. Posted using the Full Custom H.A.M.B. App!
Bisbee? I been there.... A picture helps. Casting numbers...not so much. Also look for a stamped series of numbers and letters on the top of the axle tube. And if you could give a brief description, such as number of lug studs, lug spacing, mounting setup (leafs? control arms? panhard bar mount location?) it would help almost as much as having pictures of the rearend. Also, if you pull the cover off and look at the ring gear, it has numbers stamped in it that will tell you the date it was made, and the ratio.
I'm pretty sure all the Chevy 12 bolts had the same spline count....but if you're working on a ford or mopar, that can be helpful info.
you might also take a close look for a couple (few) numbers stamped on the bottom (road side) of the pumpkin if i remember correctly. that will usually decode to the original gear ratio. of course there are no guarantees that is what's inside it now, but it's a pretty good start. there are a few guides i remember seeing that detailed how to tell the rear gearing via wheel rotation in relation to drive shaft rotation (i think). that might also be of help to you.
Turn one axle two revolutions, or turn both axles one revolution each, and count how many times the pinion yoke turns, that's the ratio. Pretty simple.
Bisbee? Not long ago my whole family lived there, not me though. My sister and brother in law use to own the Stock Exchange restaurant and my brother was on the police department.
Thanks everyone for your input. Here are a couple pics. The axle is a 6 lug with drum brakes. I am a pretty good wrench but rear ends, I know nothing about them. I can't order parts for it because I don't know what it is. Let me know if you neeb more or better photos Posted using the Full Custom H.A.M.B. App!
That looks to be a stock 1960-1972 Chevy truck half ton rear-end. They could be ordered with coil spring rear or leaf spring rear.
That is a Truck 12 bolt, and does not interchange with car rears, as far as gears, and posi order the parts for a 70 Chevy truck with a 12 bolt rear.
Thanks. Its in my 54 chevy truck with a peanut 3 speed. Looks like it has 3.08 gear ratio Posted using the Full Custom H.A.M.B. App!
I know this is an old post but I have the same rear in my truck NF3899838 ...did you ever confirm what gears is in that rear housing? Thanks
The Jalopy Journal
