Lower Transfer Case Gears

They are $1500 plus shipping plus, you have to send me your intermediate gear for machining.

FYI, I have made 27 sets now. Many are in vehicles now with two or three seasons under their belt.

Hi All,

Here are a couple updates. First, for those waiting on gears …



I have several sets back from heat treating. I do have to hone out the output gears to size. I’ll get that done the week after New Years.

For those who are on “the list”. It would be a good idea to ping me to make sure I have your info and make payment. If you have not sent me an intermediate gear or made arrangements for me to provide one, you are NOT on the list. Better tag in. Send me a PM, text, or email.

Intermediate shaft:





I want this assembly to be precision with no gaps between inside of case, bearing races, inner bearing spacer, but after considering duffer’s advice and realizing that if the bearings break in and get loose, I would have no way of tightening them up, I decided to make a compromise. I’ve shimmed the cups so that now if I bear down hard on the nut the bearings have more resistance than I’d recommend but still will not lock up. When I assemble it, I will set the nut to the correct preload but the nut will still be tight enough that I feel like the sides of the case are tied together solidly. If the bearings break in and get loose I will have just a little bit of freedom to crank the nut a little harder … not much though. I will use a 7/8-14 nylock nut as a castle nut and cotter pin do not provide accurate resolution to set preload.

Finally, a little FYI:



Broke another spur gear tooth. This was in a stock 1-1/8 shaft case, I.e. 21/39 spur gear set.
This validates in my mind that if you are running a 4.3 Chevy or bigger, with granny 4 speed you should highly consider running a transfer case with the 1-1/4” intermediate shaft, I.e. 29/39 helical set - 18/33 spur gear set.

I didn't mean to infer that the assembly moved the case walls.  But torquing the nut could suck those in just like using the expander to install the gear/bearings if any slack develops.  That could come into play as the bearings wear.  It may actually be beneficial for some adjustment.

Edited by jpet - 14 Nov. 2022 at 10:18pm

Have you checked to see how much deflection there is in the case when snugged/extended between the intermediate shaft bores?

duffer wrote: Soooo, if one has the X98 gear machined for AA's kit, you would need to remachine the race seats deeper for this set up?  …

No, actually you would need to add shims. I machined your C’bores to .485 deep per the AA drawing. In order to make the inner cones fit snug between the case frame, these c’bores need to be about .4795 deep or so. I don’t have an exact number yet.   McMaster Carr sells 50mm x 40mm x .1mm thick shims that might work. If I could find increments of .001”, it would be better. In order to dial mine in, I machined the C’bores about .06 deeper so that I could make precise shims in the lathe.

…Are you using the same Timken Set 14 bearings as the AA kit?…

Yes. I looked around to see if I could find a bigger bearing but I think set 14 is about as big as I can go and still have reasonable strength in the spool. Besides, I’m trying to keep the heat down so I’d rather use smaller bearings even if I have to replace them once in a while. They work ok on the rear axles of tandem trailers and those wheels are under significant thrust at times.

…And when are these anticipated to hit the market?  The X98 project is still on the bench but is on the queue-----------

Well, that depends. How many wheeling trips do I have to do before I can be confident that the product is thoroughly tested? With this setup, the pre-load is non adjustable so whatever “I” think is the proper preload is what everyone has to live with. I’m going with the basic rule that inboard cones are supposed to have a slight preload and outboard cones a slight clearance so I made this setup so that when the cluster gear is spun by hand, it will spin freely but not just keep coasting. Same thing as Metalshaper recommends. ….
… what I don’t know yet is what will happen when this setup is put in the vehicle and wheeled hard a few times. My experience with the AA kit is that it always loosens up a bit and I have to go back at tighten the nut. With this setup, that may not be possible. Idk. Still in R&D. Right now. I’m very busy at work but I plan to get all this in by January and run it at Winter Jamboree.

I can make you the shaft, bearing spacer and end cap. You would need to get the shims for your cups I also machined the outside surfaces of my case to make them perpendicular to the case bores. I’m not sure if that is necessary or not.

Wow! Super impressed with your ability to keep making these TCs better and better!

duffer wrote: ...Wouldn't putting "some" torque on the nut tie both front and back of the case together for more strength and maybe lessen the probability of splitting it? ...

Yes, and that is what I will do. I was just trying to make the point that the pre-load is not set by the nut via floating shaft as you described. The nut simply holds the bearings and case together. You can crank on this nut and it will not affect the pre-load.

Amazing effort and progress Jeff.