12vstrokethis

my 5th-gear has came off twice in less than 6 months what am i doing wrong i am tried of screwing with what do i need to do to make it from coming off

dezlsmkr

If it is that bad i would say the fully splined shaft should take care of it.

Fueling around

I run an auto, but still listen about the issues.
Mike (Mike's Custom Trucks) repaired tranys with a fully splined main shaft and improved nut, but still had a returns after a few hard miles.
Mike discovered an average main shaft and gear have too much clearance in the splines and eventually work the nut loose again.
He changed vendors to a press fit set and hasn't had a single return.

got...DIESEL?

I agree...mine is from blumenthals, who use a light press fit on a full spline, followed by a thrust washer, then a spanner nut with TWO set screws and a flange to ping into a keyway cut into the mainshaft. All of this plus 350 ft/lb of torque and red locktight.

I had to take mine apart to convert it from 2wd to 4wd, and it was a real PITA to get apart!!

Replacing the shaft with a full spline isn't a big deal, just keep all the clusters and synchros in order and you'll be fine. It may be, however, the best alternative to out of the box fixes.

Iron City

this might be an interesting read for you:

http://www.quad4x4.com/NV4500%205th%...0Solutions.htm

FMT

Iron City,

I just bought a kit from the quad 4x4, couldn't get the best kit because they are backordered 3-6 weeks, My fifth gear just went out again, 3rd time.
cost 975 for the parts. Haven't found anyone to install yet, just moved to Northern VA. Hope to get it installed next week. I will keep you posted on progress.

RCW

You can go with a full splined shaft, but also get a new 5th gear when you do if there is any evidence of a shiny wear ring halfway inside the internal splines where the old gear rode half off the OEM shaft under load. I get mine from SixStates, and the entire package runs maybe $325. Just make sure the gear and new shaft work snugly but are free with light oil on the spline. If there is any binding, use diamond paste and relieve the gear and shaft splines just enough to clear the bind. I never use the press on type shafts, just make sure the case is properly shimmed when reassembling.

Red loctite will hold the rear shaft nut, but let it dry before you fill the unit with oil. Also get the nut with the set screws from the edge, not the gland type. The gland type never holds. If it is necessary to remove the nut at some time in the future, just heat the nut to 400 degrees and the red loctite will release.

12vstrokethis

what about just putting a little tack of weld on the nut to the shaft or double nuting it and puting a tack of weld. but would the weld through the balance off and through out the bearings

robert chilton

I havent taken one apart to see if it will work for sure but I am thinking of putting the whole assembly together then crossdrilling it and installing a roll pin. This way it would have to shear the pin to loosen up. I have never heard of a roll pin coming out under centrifical force so I am thinking this is the best low dollar fix. Any thoughts?

Dr. Evil

Ive heard of a couple of guys that have welded the nut on....not sure if I would recommend that though...

Could be worse...you could have an auto...

99 cummins

The weld on the nut is always a bad thing, the heat from the weld distorts the metal just that hair bit and in this mainshaft even if you can't feel the distortion it is still enough to do bad things over time.