'90 Transfer Case Identification

[Demon33]

Fron Jack's Transmissions:
Q: Do I have a 22-spline or 23-spline T-case output shaft in my DSM?

A: You can figure this out without pulling your transmission. If the whole case is aluminum, it is 22 spline, if the front half is cast iron and the other aluminum it is 23 spline. If a magnet is attracted to the case that is case iron, if it isn't it is aluminum. 2G's are all 23.

Many years ago, before I knew about the trasnfer case recall, my transfer case locked up on me while driving on the freeway. I had the car towed to a local shop that change out the bad transfer case and installed a new (used) one. I never questioned it and have been driving the car for the past 13 years without issue.

My question is this- is it possible to have a 22 spline input with a cast iron case like that of the 23 spline described above. My transfer case has a dark colored cast iron front half and an aluminum back half like that of a 23 spline case. However, when I counted the actual splines on the transfer case input, there are only 22 splines. My car is a '90. Were these early transfer cases half cast iron or did the shop somehow switch the front half with at 23 spline but still retain the 22 spline input? I'm confused.

 

[dsm-onster]

It MUST be a 22spline if you have a 22spline transmission. There's no way around it. You can give us the cerial number on your transmission. Or the vin on it. Either will tell us which tranny you have. Or you can drop your transfer case real quick and know for sure. . .

 

[e85_4g63]

Is there something wrong with your transfer case? I don't understand what your asking here.

 

[Demon33]

It MUST be a 22spline if you have a 22spline transmission. There's no way around it. You can give us the cerial number on your transmission. Or the vin on it. Either will tell us which tranny you have. Or you can drop your transfer case real quick and know for sure. . .

I know for sure that it is a 22 spline, as I dropped the TC to troubleshoot a problem I thought I had with it. Had I not dropped the TC and simply went by the look of the case, I could have mistakenly thought it was a 23 spline TC.

Is there something wrong with your transfer case? I don't understand what your asking here.

Nothing's wrong with it, but I was getting ready to buy a rebuilt tranny using the core/exchange program Jack's offers and I needed to include the TC spline count with my order. Looking at the exterior of the case, I would think that it's a 23 spline because it has a cast iron front half. However, I pulled it off the tranny to verify because I know '90s came with 22 spline transfer cases.

So what I'm asking is could a '90 TC (22 spline) have come from the factory with a cast iron front half like mine or should it be all aluminum like described on Jack's site which would suggest the shop that repaired my car many years ago pieced together parts from one or more TC's?

 

[dsm-onster]

Ask Jack. He's getting your business. I KNOW he would be willing to talk with you about it. Tell us what he says. I'm curious about your case as well. A durable replacement for the aluminum 22spine transfer case would be a nice thing for those willing to push their 1990 drivetrain.

 

[Demon33]

Ask Jack. He's getting your business. I KNOW he would be willing to talk with you about it. Tell us what he says. I'm curious about your case as well. A durable replacement for the aluminum 22spine transfer case would be a nice thing for those willing to push their 1990 drivetrain.

For sure, I'm calling him tomorrow. It's too late to call tonight and I just thought I'd try to gather as much information about it as possible before I called. I'll keep you posted.

 

[DSMopar]

Maybe Jack's full of crap? Here's the 22 spline off my 91 AWD talon, pretty sure it's the original too. It's for sale if anyone cares .

 

[Demon33]

Maybe Jack's full of crap? Here's the 22 spline off my 91 AWD talon, pretty sure it's the original too. It's for sale if anyone cares .

I wouldn't go so far as to say he's full of crap. I've heard too many good things about his services to think that. I'm sure many would agree with me. It's probably just an oversight, typo or mistake. We are all human afterall. I'll call him tomorrow and clear things up. Let's stay on topic and not turn this into any type of bashing. I'm simply trying to verify whether or not my TC is as is should be form the factory.

Thanks for posting a picture of your transfer case. Mine is exactly the same. Again, I'll call Jack's in the morning to get more information.

 

[e85_4g63]

Well a good way to tell is just pull the transfer case off and check. I mean seriously it's only 5 17mm bolts that hold it one. I understand what your saying about is there a way to check with the case in the car though. I'm going to be a little rude here perhaps but, our cars are all but 20 years old and things get swapped so many times your only choice is to pull it and check. Sucks but that's how it goes.

 

[Demon33]

Well a good way to tell is just pull the transfer case off and check. I mean seriously it's only 5 17mm bolts that hold it one. I understand what your saying about is there a way to check with the case in the car though. I'm going to be a little rude here perhaps but, our cars are all but 20 years old and things get swapped so many times your only choice is to pull it and check. Sucks but that's how it goes.

In my original post, I did say that I actually counted the splines myself- 22 splines. And it was a little more than 'only 5 17mm bolts'. I had to pull the downpipe which had rusty nuts and bolts that made the job a little more difficult.

I didn't include this in my original post, but I am the original owner of my car (20 years and counting) and have only had it out of my sight for repairs a couple of times. One was when the TC was being repaired as I outlined in my OP and the other was when the dealer was doing the TC recall fix.

I'm not asking how to identify a 22 or 23 spline case based on visual cues. I'm simply trying to get a second opinion to verify whether or not the information I have is correct because if it is correct, then that would suggest that my TC is not a stock '90 unit. Until now, I've never had the TC off the transmission so based on the information that I found on how to identify it with it still attached to the tranny, it left me with some doubt. That's the reason I pulled it and counted the splines myself. I know for a fact that '90's had 22 spline transfer cases and that sometime mid '91 they were changed to 23 spline.

As DSMopar pointed out, his transfer case is the same as mine- half aluminum and half cast iron which supports my theory that the information on Jack's sight is wrong for at least our two cases. I thought my case might be unique, but as DSMopar pointed out, it's not.

I'll call Jack's this morning when I get a free moment to see if I can't clear this up.

 

[Demon33]

UPDATE:

I contacted Jack's Transmissions and he verified that there are in fact some early transfer cases that are 22 spline and have cast iron front cases like mine. These are rare and the majority of the 22 spline units have all aluminum cases. So I guess if you have a '90 or early '91 transmission with a transfer case that has a cast iron front half and you need to know the spline count, you'll probably have to drop the transfer case to verify the exact count.

Thanks to everyone who posted.

 

[dsm-onster]

Thank you for following up! Now is the 22spline iron transfer as strong as the 23spline? 23spline units are known to take more abuse. Is it because of the case or because of the internals? Did he mention this? I suspect the case is what makes the difference: keeping the gears together with a strong case usually is what's most important with differentials and transfers.

 

[DSMopar]

Let me be clear I wasn't bashing Jack, he's helped me out in the past. A poor choice of words on my part.

That said don't assume anything, as we found out iron case does not = 23 spline. I bought a mistery trans to rebuild when I first got the car and I made the mistake of holding the original trans output shaft to the new one and concluding them to be the same. Well one tooth difference doesn't make for a huge visual difference. I ended up going back to the trans guy and buying his T-case as well. So be sure you count them rather than visually compare...

As for being stronger, as far as I know the 22 spline T-case is less desirable simply because the 22 spline output shaft is weaker. I'm betting you'll twizzler your 22 spline output shaft long before you blow up an aluminum 22 spline TC.