Ok, i'm trying to mate a TH 400 to my Dana 20 and need to know what all is needed. It looks like I need an adapter, but do I need a different output shaft as well? I don't know if this 400 came from a 2WD or 4WD, but can find out. I don't actually have the transmission in my possession, but should be able to find out what it came out of later this evening. Basically, I'm needing to know if all TH 400's had to have this adapter and shaft or if it was just certain circumstances. It appears that all of them needed it, but want to make sure. Lastly, can a person buy just the shaft? I've located a couple of stock adapters, but they are bolted to the Dana 20 so the shaft isn't available.

Or, does anyone out there have what I need for sale? I can't afford them from Novak or Advanced Adapters...but could buy a used set from someone if they're fair priced.

Thanks - Adam

You need a Th400 with the short 4wd output shaft. Some of the 2wd TH400's use a shaft that is the right length, but it does not have the o-ring groove in it that is needed to seal inside the adaptor spud shaft.

what type of motor are you using,, the early jeep wagoneers 73 or so came with th400 that bolted to the d20with a factory adapter. If your on a budget i would look for one of these IMO

Old Jeep - can the O-ring groove been seen by the naked eye if the tranny is assembled? Since I don't know how the adapter bolts up or where the seal is that you're talking about...I'm not for sure how to tell if I'm getting the right tranny. The guy I'm buying from builds a lot of custom 4x4 rigs so he should know if it's what I'm needing...but then I'm relying on the seller to tell me the truth. He seems pretty reliable, but I don't want to end up going back and beating my money out of him. Can you give me an idea on where to look for the groove? I appreciate you help...it's definitely helped out already.

Otter - I'll be running an AMC 360 and the tranny is for an AMC motor, not a Chevy. Yes, I'm on a little bit of a budget so the stock would be preferred right now. I've found some stock adapters, but none of them have the output shaft. The guy I am buying it from says it will need an adapter kit (adapter and output shaft) so I'm guessing it's not going to have the right output shaft on it. I know Novak and Advanced sells the kits, but they are asking WAY too much for my blood. I'm sure after selling bone marrow and blood for a few months I could afford one of their kits...but I don't know if it's worth that!

Anyway, thanks to both of you and any more help would be greatly used and appreciated!

Adam

Yes, the o-ring is right behind the splines on the Th400 output shaft.

You can see it in this picture - ignore the plate on the back of the tranny, that's my custom clocking adaptor ;)

http://www.oldjeep.com/images/winter0304projects/Adaptor/Dcp_2388.jpg

Do all Dana 20's use a bull gear input??

Originally posted by CJeep77
Do all Dana 20's use a bull gear input??

It's not a bull gear input. The adaptor has a spud shaft built into it with a special input gear attached to it with a snap ring. You can see it in this picture:

http://www.oldjeep.com/images/winter0304projects/Adaptor/Dcp_2385.jpg

[QUOTE]Originally posted by oldjeep
[B]

It's not a bull gear input. The adaptor has a spud shaft built into it with a special input gear attached to it with a snap ring.

That's still what I call a "bull gear" input. Is that a factory adapter, or aftermarket???

Originally posted by CJeep77
[QUOTE]Originally posted by oldjeep
[B]

It's not a bull gear input. The adaptor has a spud shaft built into it with a special input gear attached to it with a snap ring.

That's still what I call a "bull gear" input. Is that a factory adapter, or aftermarket???

That's a factory Jeep TH400 to Dana 20 adaptor. They used them behind some AMC and Buick TH400's in wagoneers, J trucks and commandos

just one other thing to add to this,, when you do find an adapter and shaft etc. There is a bearing in the adapter. You cant get at the local parts store. Supposedly it crosses to a bower 210. I am going tomorrow to pick it up. I think i found one at the local bearing place. I am in process of putting a d20/th400 in a jeep.
If i come up with any other issues ill let ya know

Originally posted by oldjeep


It's not a bull gear input. The adaptor has a spud shaft built into it with a special input gear attached to it with a snap ring. You can see it in this picture:

http://www.oldjeep.com/images/winter0304projects/Adaptor/Dcp_2385.jpg

You have a Bridgeport?!

Originally posted by Oxjockey


You have a Bridgeport?!

Nope, but a friend of mine does ;)

Alright...now you've got my curiosity up. What is a spud shaft and what is a bull gear input? I think I know what the spud shaft is...but not 100% sure. The bull gear has me completely lost!

Otter - thank you! Please let me know how things go and what I need to keep an eye on. I have a tendancy of breaking sh*t so I'll need all the help you can offer from experience. My grandmother used to say I was like a bull in a china closet...what I didn't break I sh*t on! There was a little humor behind it...but a lot of truth as well.

Anyway, thanks to all of you. I'm slowly catching on to what I'm needing to look for. As before, any more info that could be given will be greatly appreciated.

Thanks for the great posts!

Adam

look to adaptors from 67-73 in fsj's and 72-73 commandos with th400's they are out there, The swap isnt that bad and the mainshaft can be accompanied by a shift kit when you are swapping it.

Cool, that helps me narrow down my search. You don't happen to have one you want to donate to my project...do you? :D

Thanks - Adam

The weak link on those Dana 20/ T400 aluminum adapters is the overhung drive gear - it has enough leverage to shove the bearing right through the adapter case if you wheel hard. I machined the adapter to fit another bearing on the Transfercase side and it eliminated this problem.

My Dana 20 out of a 68/70 wagoneer had the adapter and I put a mid 70's Chev 4x4 output shaft into the Turbo 400 to mate up.

I don't suppose you took any pictures...did you? Since I don't know exactly what the adapter looks like, it's hard for me to follow what you're saying. I think I've got a good idea of where it pushes through, but don't understand where you machined it to fit another bearing.

Can you tell me, are the aftermarket adapters prone to breaking like this? I've heard this before, but generally it's about the stock adapters. I'm now curious if Novak or AA has this similar problem since they're aluminum as well.

THanks - Adam

Originally posted by alc24073
I don't suppose you took any pictures...did you? Since I don't know exactly what the adapter looks like, it's hard for me to follow what you're saying. I think I've got a good idea of where it pushes through, but don't understand where you machined it to fit another bearing.

THanks - Adam

I don't have photos - went to a 205 long ago, but if you look at the pic above - imagine just lifting the gears you see off and setting the new bearing in the adapter and then putting the gears back down. The existing bearing is deep in the adapter - you can see the leverage on it with that top gear sticking way out. Hope this helps.

Hey Otter...just wondering if you picked that bearing up? If so, does it look like it will work?