pro gears

[bravo]

I have a 12-bolt(truck) diff. and I am trying to find a way to put 4.88 gears. I bought some richmond gears(4.88) and I took my truck to the track and broke them. Any suggestions? I don/t want a ford 9" or dana. thanks in advance....

[nxtruck]

Tell us more details about your truck. How much power is it making? What does it weigh? I have broken a set of Richmond 4.88s in my truck 12-bolt, but have since added a braced rear cover and studs in the caps instead of bolts and haven't had anymore problems.

[bravo]

i haven't weighed it. I have a 496bbc. I ran it twice and ran a 11.6x on motor. On the third run I sprayed and I nearly hit the wall due to my diff locking on me. I left on 4k. I built my own 4-link and run 32" tall tires. Half of the teeth are gone...

[nxtruck]

The " half of the teeth are gone" part sounds like what happened to me. I'm assuming you are running a spool and a/m axles. When you said that you leave at 4000, is that with a transbrake or foot-breaking? Powerglide or 3spd? If you're running a brake, this changes things some. If you don't load the driveline before setting the brake, this could be the result. If you're footbraking, however, I don't see any reason why the street gear wouldn't work. I spray mine out of the hole without any problems, foot-braking it BTW. The things I'd recommend to make it live would be a spool, 33 spline axles, a braced rear cover, studs in place of bolts in the caps, and possibly weld the tubes to the center section.

[71chevytruckguy]

i agree with what nxtruck said. another thing i'd do to is get a mark williams billet bearing cap for it. Im running one on my 12 bolt with 4.88 gears. I drop the clutch @ 4500, its a 4 speed, haven broken any teeth but have twisted a housing because I fogot to weld the axle tubes to the differnal. Chris.

[bravo]

yes I have moser axles and leave on the brake. I have a 400 trans with reverse **** pattern. I have the tubes welded, and have c-clips. what do you mean by loading the drive line? So nobody makes pro gears for a 12 bolt trk? I heard that they make a bearing for the 12 bolt car pro ge3ars that will work on my 12 bolt trk. Anybody hear of this? I can put a ford 9" but then i would have to get it narrowed, order axles,and all that goes with it, plus I already bought the moser axles for the 12 bolt.

[69trk]

I also have the truck 12bolt with moser 33spline axles. I'm going to change my original 3.73's with some 4.10's. I haven't looked into any progears as of yet, but i guess that i'll need a set as soon as i spray mine. Glad you guys said something about welding the axle tubes. I need to do that. By the way, give us some specs and times on your truck. looks good

[nxtruck]

Originally Posted by bravo

yes I have moser axles and leave on the brake. I have a 400 trans with reverse **** pattern. I have the tubes welded, and have c-clips. what do you mean by loading the drive line? So nobody makes pro gears for a 12 bolt trk? I heard that they make a bearing for the 12 bolt car pro ge3ars that will work on my 12 bolt trk. Anybody hear of this? I can put a ford 9" but then i would have to get it narrowed, order axles,and all that goes with it, plus I already bought the moser axles for the 12 bolt.

Sounds like you have most of the things covered. By " loading the driveline " I'm referring to getting up on the converter just a bit before activating the brake, so as to take any slack out of the driveline before releasing the button.
I, also, have heard that supposedly you can use a different pinion brg. on the car gears that will allow them to be used in a truck housing. I believe that I got that info from Moser, so you may want to check with them on this. I personally haven't seen a pro gear for the truck 12-bolts, so this may be your only route to putting pro gears in your housing.
Good luck with it, whichever way you decide to go...

[71chevytruckguy]

The only difference betwween the pro gears and regular gears is the hardness of the gear. The harder the gear is the less it will bend before it breaks. The pro gears are less harder than the street gears because in racing, a bend tooth it better than a broke tooth. Everything I've read says not to use the pro gears if you plan on running on the street.

Im running a Mark Williams billet bearing cap mine with a moser 33 spline spool and axles. Mark Williams' website said it for a 12 bolt, didnt specify car or truck, but its worked so far.

If your still running c-clip alxes, PLEASE FOR YOUR OWN SAFETY, get a set of c-clip eliminators on there before you break an axle and got down the track on three wheels. Been there and its not fun at all.

Here's a link for an excellent write up from Mark Williams on beefing up a 12 bolt rear end, mainly setup for car rearend but about all of it can be used on a truck axle too. Chris.

http://www.markwilliams.com/bulletproof.aspx

[nxtruck]

Yeah, I misread that part of your last reply, bravo. If you still run c-clips,then, by all means, convert it over with c-clip eliminators. Once you eliminate the c-clips, you can install a full spool and get rid of the posi unit or mini-spool, if you're using one of these.
If you've already done all of this, great! I just wanted to clarify this beforehand.

[bravo]

I'm working on the c-clip eliminators. thanks for all the help!!!! here are some pics of my hooptie..

[bravo]

Thanks for all the good info.