RockEater Gears for the D18/D20 Transfer Case

chasendeer wrote:

Does the first gear have the sprocket on back for PTO?

I presume you are talking about the 6 spline transfer case input gear, and yes it has the sprocket teeth.

1947 CJ2a #119929 "Gus"
1951 CJ3a #451-GB1-24268 “Newt”

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I don't see a new sliding gear...

Supposed to re-use the Dana Spicer sliding gear ?

Also I see both a transmission mainshaft gear (output) and the O.D. bowl gear.

You have to purchase both of those ?

Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

oldtime wrote:

I don't see a new sliding gear...

Supposed to re-use the Dana Spicer sliding gear ?

Also I see both a transmission mainshaft gear (output) and the O.D. bowl gear.

You have to purchase both of those ?

Sliding gear does not come with it. I don’t think Jack even makes one. Im using my existing sliding gear.

smfulle wrote:

[QUOTE=oldtime]

I think Rick is just hedging his bet just in case his overdrive grenades on the trail. It’s probably something I should consider with my Tera gears and overdrive. Having a recovery option when you are on the trail is good.

That’s exactly right. Hedging my trail rides😉 Standard set comes with the regular transmission output gear. Bowl gear is additional cost.

1947 CJ2a #119929 "Gus"
1951 CJ3a #451-GB1-24268 “Newt”

My Videos

Wow, never thought replacing transfer case gears would be so involved😳

Here’s what Gus looks like right now. Just waiting on parts...

1947 CJ2a #119929 "Gus"
1951 CJ3a #451-GB1-24268 “Newt”

My Videos

jpet wrote:

You are putting the transfer case gears in your engine!!

No wonder it seems more complex than you thought!!

Stan
48 CJ2A (Grampa's Jeep)
59 Chevy 1/2 ton
Grampa's Jeep Build Thread

I guess I will go with the terra lows. I don’t want to pull my engine!!!

Jay

For some reason, when I started this journey, I was under the impression that you had to have a large hole case. I don’t think that is necessary after doing the install. You may have to grind more in the top of the case than if you used a D20 large hole case, but I don’t know for sure. The one thing you do have to have is a 1.25” intermediate shaft. If you have that, then I would give it a try. At least give Jack O’Brien a call and see what all might be necessary with a small hole case. If you are going to run stock motor, I don’t think it would really be necessary to do the tapered bearing intermediate shaft. I really dont’ think its worth the money for these little flatties. I opted to just go back with the 1.25” shaft (albeit, one of Novak’s hardened USA made shafts).

In hindsight, that’s probably what I should have done, and may do in the future. Using a large hole case has presented some potential body tub/case interference issues (will confirm this when I put my tub back on the chassis) as the D20 large hole case has a pronounced larger cast in the PTO area of the case. This larger diameter of the case looks like it may cause contact with the tub. If so, I will have to lift the body with some thicker rubber body mounts (looks like nearly an inch by just eyeballing it). I will document this in the future. Also, the boss for the pivot ball stud (for the clutch lever tube) is protruding significantly more than the original D18 case. I had to grind 1/2” off to be able to fit the clutch lever/tube on the ball studs. I’ll also show this in upcoming posts.

1947 CJ2a #119929 "Gus"
1951 CJ3a #451-GB1-24268 “Newt”

My Videos

I have a spare "small hole" yet 1-1/4" shaft case from an m38A1. Will the 3.6 gears work in this case, or do you have to have a large hole case?

Also - if the large hole case is required, is it possible to machine a small hole case into a large hole one?

Yes any gear sets can be put into a small hole case however larger diameter gears may notably thin the case wall.

Very large gears will require case welding.

If strength is a concern (big engine extreme low gearing) then know that all big hole cases are of a stronger casting design.

A small hole (3-5/32" index bore) will have to precision bored in order to turn it into a big hole case (4" index bore).

Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

Cool beans. I got mine yesterday and I'll have it in tonight.

Your drive flanges look cool

Have you done anything with the springs yet?

CJ2A #29110 "General Willys"
MB #204827 "BAM BAM"

"We do what we can, and we try what we can't"