79 Dana 20 from a cj

I know very little about transfer cases and the such so bare with me.

The Dana 20 in my 73 commando is on it's death bed (I6-th400).
I can get a dana 20 from a 79 cj

Would it fit?
other than the shift linkage what outer things should I look out for?

Shift linkage hard to swap and also know of anyplace to get a rebuild kit for the linage (internal guts)?

Thanks in advance.

 

It's basically the same TC. There's a chart on the Novak site that lists the gears used in the D18 and D20 for various apps. Look at the chart and see if the TH400 gear will mesh with the gears in the '79 D20. Go to www.novak-adapt.com and look at the article on the D20 in the data base.

If I had to change the linkage, I'd say the heck with it and rebuild the one I have. It's not difficult. Parts are easy to get and there are several places with instructions. You'll need a dial indiator, but they can be had at Harbor Freight and such for less than $20. If you get into trouble, ask for help here.

Regarding the linkage, I'd take it apart, clean & lube and see if that was enough. I expect it would be.

 

Hte imput gear for the normal stick shift d20 is a 6 spline unit, and the th400 version is a 10 spline. BUT if you have the correct input gear, it will work in any factory d20 case. Meaning that all you have to do is use the input gear from your old case in the new one. The input gear is commonly lost when a d20 is removed and sold, since it remains attached to the output of the transmission when the t-case is removed.

You would have to swap shifters and linkages.

What makes you think your d20 is dying?

 

To answer Both

I had it in the shop to have some other work done. Told them to look at the shifter as it was having problems staying in 4HI.

They pulled it apart and told me the bushing where worn, then they also told me that my rear output shaft is worn (and that's what's causing my vibration when driving).
All so said the shifter was full of water.

I think someone was in there before and may have lost a few small parts.

I haven't checked it out yet as I'm in office cloths but when I pulled into work today and parked by the time I got out of the jeep there was a puddle under the truck. Looked closer and its was all coming from the transfer case.
Guessing rear seal let go.

When I get home and changed I'll get a better look.

 

Herm the overdrive guy .com
He has the rebuild kit you need.
Reasonably price with good bearing ect.
Not that hard once you have done one.

Shouldnt be that bad at a shop price wise, if it sounds pretty high, then they are gouging you.

They are good rebuild canadates because they are simple.
The case needs to be sound and the gears shouldnt be chipped or overly worn.

That said your leaking because of the rear output being bad.
but the shaft maybe ok could be just the bearings.
Wont really know till its apart.

If it was me and I didnt want to do it myself.
I would take it out and then bring it in.
Clean it off a bit then you should get a decent price on fixing it.

I would tell Herm exactly which case it is based on the rig and tranny and then get my kit from him.
The shop is likley to get the cheapest kit they can find.
Make sure to have the output splines before the yoak goes on rtv slightly this will help with leaks.

 

THe shifter on the commandos is, IMO, a sloppy piece of junk. My cj had a commando d20 in it with the commando shifter. It was soooo sloppy that i found at least 2 modes that the t-case wasnt supposed to have. 2 low rear only, 4 high front only. I changed cases and got one with a cj style shifter. Its much better.

FWIW, I had my d20 proefessionally rebuilt, along with a teralow kit, and it still drips a little gear oil. not a lot, but some.
If i were you, I'd swap over to teh cj case, and make extentions for the cj style shifter to adapt it to your application.

 

The shifter is the U-pattern shifter, and was used in the full-sized Jeeps with a Dana 20 as well as the Jeepster/Commando. I have one in my truck, and it works fine. If you have trouble with it or need parts, ask on the full-size boards like www.ifsja.org (as well as here or on the Jeepster boards). I'd guess the shifter from a Wagoneer will be the same as yours except for the lengths of the support tube and shift rods.

There's a pretty good picture in the manual:



Not a complicated assembly. I'd suggest you take it apart and fix it.

 

Twin sticking your original case is not hard.
theres a guy on Ebay who sells them for your aplication for just over a hundered bucks.

I made my own I use the pipe that the stock one bolts on, and some D 18 sticks I had.
There was little fabing but not much and it saved me a 100.00$
Here are some pics

 

It's common for the pin sticking out the side of the shifter stick to get worn out. I've repaired them with mixed results. The top has to be shimmed for it to work correctly also.

The shifter assembly for the CJ is a different animal and the whole front nose cone must be replaced to use it along with the shift rails. It will also sit in the wrong place most likely and these are notorious for getting worn out just like your existing shifter. If you can do any fab work, I'd rebuild what you have, maybe using the other transfer case for parts, and then convert to a twin shifter configuration. It gives more options and is less problematic.

 

This pin I presume?



There's not much demand for these shifters - If the pin is worn, you should be able to get the whole assembly cheap or free from a Wagoneer or Jeepster parts car.

 

That's the one Timgr. I know around here they are hard to find in good shape so bring a premium in price. Last good, tight operable one the shop had sold for $85 or so dollars and we didn't have it long. We have a bunch of old worn out ones though... May not be the case in other areas though. We have tons of Waggy's/Pickups still on the road here so people are still looking for the parts for them.

 

Huh. I guess I assumed they were easy to source. I hang around the IFSJA forum a lot and haven't seen any WTB or for sale ads that I can recall - thus I concluded there's not much demand.

You could try posting a WTB on www.ifsja.org/forums and see what happens. Here's a thread http://www.ifsja.org/forums/vb/showthread.php?t=81791&highlight=shifter

 

I don't know why but I didn't think about IFSJA. Very good resource for stuff like that. Like I said, may be all over the place in other areas, just not here so your mileage may vary

 

Mine's on cl right now.
PM if you want it for free + shipping.

Oh and it works not new though of course.

Oh and one thing I learned on the fullsize site was.

The shifter rail on a u-shifter setup has a softer taper on the 4wd shift rail so when you twin stick it it pops out of gear easier than it should.
The fix is to weld some material on the rail and make the ramp more abrupt like a cj twin stick rail would be.
I did this during my rebuild and wasnt hard to do.

You could search it on the fullsize site and see plenty on it.