Lower Transfer Case Gears

All this AND a weekend of wheeling too. Good thing sleep is optional for you.

Slowly but surely, I am ironing out the kinks in production. Testing is a lot of work but all forward progress. I am in the process of making more gears now along with extra input gears for experimentation. This has been the trickiest part because the 6 spline inner changes after heat treat and it’s hard to predict, at least on the 9310 material. The 8620 I think I have down.



These are initially broached with a production pull broach but I’ve had this special single tooth broach made to chase the splines and make them a little deeper so that when they come back from heat treat, they are within tolerance. Apparently Jack O’Brein had the same problem:



This is the input gear from my Rockeater 3.6 set. The internal spline measures, 1.384, I.e. .009 clearance between it and the shaft.

Edited by jpet - 27 Apr. 2022 at 3:49pm

Jeff, are you thinking about marketing those girrdle plates?  Are you going to make a piece to join the two?  I was actually going to do the same thing but mine wouldn't look near as nice.  Maybe making the cover and base griddle out of a single chunck of 6061.

jpet wrote: duffer wrote: Jeff, are you thinking about marketing those girrdle plates?  Are you going to make a piece to join the two?  I was actually going to do the same thing but mine wouldn't look near as nice.  Maybe making the cover and base griddle out of a single chunck of 6061. Sign me up! Yes, and yes. I think I want to remake the PTO cover so that it has a flat bottom that extends flush to the pan girdle. Take the radius out of the pan girdle and bolt the two together. Mine are made of steel and the bolt holes are on-size in hopes of keeping it rigid. I can make you a set. Do you want to send me an 18 tooth intermediate gear, use the 21 tooth one I have already, or wait till I’ve run my set more?

Edited by Stev - 09 May 2022 at 1:25pm

Thanks for posting that Steve. Can’t wait to see “the Saint” in action next week. There will be 4 Jeeps running these gears at Southington and the Spring Reunion. 3 of which are in the “Locker Stocker” class and of course BAM BAM.   The V6 with 4 speed is still in experimental mode but I am very close to pulling the trigger on a production run for the 4 cylinder group.

Here is a little info from the R&D department at Sim Products:









This 18 tooth, 6DP gear will be easier to make than the 21 tooth 7DP gear because, there is a bigger gap between teeth so I can use bigger tooling. This test is made from Aluminum. I’m getting ready to run one out of 8620.

I’m actually still thinking of keeping the bolt together design to save on material and so I can keep more of the work in house. I think I’ve proven to myself that the bolt together shrink fit design will not be the weak link in this assembly.

If anyone is more than a tire kicker and wants to get in on this next run of gears, please PM me. I have high hopes that these gears will take the locker stocker class to the next level. thanks!!

Edited by jpet - 09 May 2022 at 1:39pm

Got the replacement input gears finished. These are to fix the 9310 input gears that shrank after heat treating. I’ll finally be able to finish up duffer’s set snd get them out hopefully tomorrow. Thanks for your patience. It looks like the broach I had made is gong to do the trick.

This weekend was another 2 days of what I would call abusive wheeling. Lots of horsepower in Midwest muddy creeks and ditches. I decided that if I am going to gun it hard, I would not use low range but to go to granny low in high range. Less stress on the spur gears and puts all the load on the X98 super gears. At one point I tried to jerk an SXS out of a ditch backwards with my kinetic rope and I ended up in permanent neutral .... turns out that the torque was so great that the force of the helix on the gears stripped the locking nut right off:



To be fair, this is a nylock that I have used more than once. I had a stock nut but the force also messed up some threads on the end of the main shaft.



... to solve this issue, I started the jeep, put the tranny in reverse and chases the thread with a 3 sided file. Then flush the case and replace the oil.

Gears look great. I put a lot of torque on these gears this weekend in mud holes and climbing out of slick ditches and I purposely put some power to them. If they are going to fail, I’d prefer it to be close to home. Even though I did break the slide gear, last April, the X98 supers have gone through

EJS
Rush Springs
Southington
Rausch Creek
Terry’s farm.

Edited by jpet - 19 June 2022 at 8:59pm

I think this is one place the early castle nut/cotter key main shaft would be the better choice for this.  That nut appears to be much more robust with more thread engagement.

Edited by duffer - 20 June 2022 at 11:24am