Woodstock

Just for fun, I mocked up the overdrive.

And this is what it would look like, if I wasn't adding a small apartment in the rear.

With the PTO adapter, and PTO. This will add about 7" to my PTO driveline.

I'm now joking that this thing could be further back than my rear diff in a 80" WB rig.

 

Room for the mother in law...lol. What is the weight and is there a brace involved?

 

No brace, the last mount is on the transfer adapter. It only weighs 10 lbs or so, all aluminum.

 

It just looks like a big lever but I suppose it has been done before with no ill effects. Are you planning in a double cardan for the rear drive shaft?

 

Yeah, that'll be seriously far back. Can't imagine regular u-joints being happy with the angle of the dangle.

 

I was referring to the flange output yoke on the transfer case. He is spring over and unknown to me springs.

 

The spring over doesn't lift it too much because of flattish YJ springs, reverse eyes, and shackles through the frame. And since the 18 output is low, and I have a high pinion rear end, it's really not bad. About 7* driveline angle, which was huge improvement over the old low pinion 44 which had 17* DL angle. When I get this in, I'll get a photo of the driveline. So it's just the winch driveline that will be longer by moving the PTO back.

 

All painted up, ready to go in. I can't put this off any longer.

One last thing, put the levers on and see if it shifts correctly. All is good.

Didn't get any photos, but I put a gasket on the mating surface with right stuff sealant, laid down on a creeper, got it on my chest, rolled under, hefted it up on to the adapter and crossmember, then got a bolt in. Went pretty well. Then installed all the other bolts. Next is the overdrive bowl gear, and the special washer and spring clip.

I have my transfer case tucked up pretty high, so it's hard to look into the hole to see what I'm doing, so I painted the small parts white to add some visibiltiy.

The bowl gear slides right on, then torqued to 120 lbs with a 1/2" socket extension. Then I played with getting the washer lined up, this can be a patience test, and after about 50 tries, and moving it around to several of the possible combinations where the tang fits in a slot, I finally got it. Then the snap ring goes in the slot, done. Now the outer housing can go on, and I dummied the shift linkage to see how it will fit. I will have to heavily modify the linkage to reach my planned shifter location.

Next, I dummied the PTO adapter on the overdrive. This is going to be a problem, the PTO is now farther back and contacting the body hat channel in the trans hump. I will need to lower the trans/transfer case to make a little room.

 

Looking great. I like the ideer of painting the lock ring and keeper. The clearance makes me glad I built in a 1" body lift.

 

Thanks, everything was fine until I moved the PTO back. I do have a little body lift already, and since my crossmember wraps around the side of the frame, and is drilled into the frame on the sides, I can't just add a spacer under the frame to lower it.

 

I hear you. You could make a plate that bolted to the floor. Think shifter boot trim ring. Hack what you need out of the hat channel as it is thin there anyways.
A 1/8" piece of plate bolted to the floor would tie in the 2 sides and cover what opening is there with a shift boot. The hat channel is going to be compromised anyway.
Might be easier than a re-do of the cross member and no loss of clearance. Funny how one modification requires three others to make it work.

 

After looking at this, the solution is to shorten the transmission mount that rests on the adapter. This way, I don't need to mess with the crossmember. There is a piece of 1-1/2" box spacing the stock T90 mount to the Sm420-to-D18 adapter. So I could just take 1/2" out of it and get the clearance I need to miss the body hat channel. All I need to do is take the weight off the gear train and pull the T90 mount and spacer out. Now a new problem, the adapter weld is broken. Just gravity holding it in. That might have been one of those noises last summer.

The broken weld at the top, the 1-1/2" spacer, then the T90 mount. To fix this, everything has to come back out.( oh joy). The bad news is this is not a AA adapter, (that I have a spare of), and different spacing. So I can't just replace it with the AA without driveline mods. The good news is it is steel and easily weldable once I get it out. I dug back into the archive to remind me what it is.

Found it, as torn out of JP mag. The Rube Adapter. $400 bucks.

First step going backwards, remove the overdrive, the transfer case, and the adapter, which means drain the SM420 oil. Then I shortened the riser 1/2", and used 1-1/2" box for the riser.

Painted up, ready to go back in. Hey, if you only do everything once, how are you going to learn, right?

 

I am glad that you found a solution and get to do a repair. I like the name of the adapter "Rube". Uses a stub shaft and looks heavy duty.
This is better than a total rework of the cross member. Surprised you didn't gusset the riser though don't know how much strength would be
gained. Does the shifter/riser boss clear without major cutting of the hat channel?

 

There really wasn't room for gusseting because it would block access to the bolts going into the adapter. So, it's probably better than Rube ever intended with the box tubing in there. Good for another 20 years I hope. I will still need to cut a hole in the hat channel for the PTO shifter. I looked at my CJ5 that has this set up and I think part of the hat channel will survive.

 

After a great little vacation to the MVCC event, I am back. A few small items to address before the transfer case goes back in. I got new T90 and D18 mounts from Partsdude.

I never realized it leans back for the slope of the drivetrain. Here you can see the 1-1/2" spacer from the mount to the adapter. I thought of eliminating this, but if you do, you can't get to the rear cap bolts on the SM420, so it stays.

Also now have the front yoke from AA. This will accept a 1310 joint.

But it has a weird dust shield that hits the housing, so I found the old yoke and switched the shield.

Torqued that thing on there, and I think I'm ready to install the transfer case again.

 

I don't recall having to grind much of anything in the large index case I used. Unfortunately, I have no idea what that was actually out of except it was a side fill D20 with the shifter broken off. $15 at the scrap yard. And maybe it's a case of johnzheimer's-that was probably close to 25 years ago.

Looks good and you will like the gears.

 

Thanks John, I can't wait to try it at 119:1.

 

You could run it on the starter only or pull trains with it.

 

I didn't get any photos of putting it back in, mostly because I was by myself and had a transfer case on my chest. But it's in, and it was uneventful. I could put that off forever, but it really is just a few minutes. Then the overdrive went much easier the second time. I think if I did these more frequently (no thanks), I would get pretty good at it. I then mocked up the PTO to check clearance and where I need to cut the new shifter hole. It goes dead in the middle of the hat channel. Here is the new hole, and old hole.

Next, started thinking about the overdrive shifter. I am going to try and get it right next to the twin sticks for the 18 so I can use a 3-hole boot. I have a spare SM420 top, so I used it on the bench to start a mounting plate for the shifter.

There is a little spot I think I can use at the back of the 4 speed, just to the left of the 18 shifters.

I had this ratty old overdrive shifter cane, but I think I can straighten it, add threads at the top, and it will be fine.

Found a nicely used knob, and added a chunk of 3/8 rod with SAE thread to extend the top a bit.

 

That’s the same spot I put my overdrive on my sm420.