Full Stock Jeepy

So i'll start off by saying i'm not much of a car guy, so i'll do my best to put this in terms you can understand.

After being fed up with the binding my 249 transfer case was giving me on round abouts, i went ahead and picked up a 242 out of a 97 grand laredo. i didn't have to change the input shafts going into the transmission(thank god) so i was hoping it would just plug right in and everything would be honky dory. Once i got to reinstalling my rear drive line i pulled from the donor, i feel as though the 33 inch drive was too short, and my 249 ~36 inch(forgot length) drive line was way too long. I was hoping i could pick up a 34 inch Dline off another donor jeep at the junk yard, though i could only find 30-33 inch and ~36 inch drive lines.

i don't, by the was, plan on ever lifting or doing anything crazy, so a $200-$300 slip yoke eliminator or a custom drive shaft is out of the question.

the only option i can see is swapping the the rear portion of my 249 with my 242 (Don't know technical term) and just use my 249 Drive line, but i'm going to have to re-read my info that i found to see if that is even possible.

i do remember seeing that two transfer cases were different sizes.

oh i guess i should mention that the little rubber boot that's connected to the drive line. i don't have it hooked onto my rear line since it begins where the boot ends. i would say the drive line is a bit under half way on.

dave1123

Welcome to CF! When you say roundabouts, I'm thinking UK, right?

Here's what I would do. I've been a toolmaker/machinist for 50 years and have made custom driveshafts before for hot rods and custom cars. Find a good machine shop and have them cut 2" out of your 249 shaft and weld it back together. The 2 cut ends have to be machined square and the universal joints have to be parallel with each other exactly! As long as the shaft is straight and the weld is constant from a mig welder all the way around, it shouldn't need to be balanced. I did this on a custom car and it was stable with no vibration up to 80 mph. We didn't take it faster than that. Make the cut near the transmission end. ALSO, make sure the transmission sleeve end is the right spline to fit the 242, otherwise you'll have to use both shafts to make what you need. If your V8 jeep has a D44a rear axle, I know you will, unless the 242 came from a V8 jeep. That's rare over here. Then again, it's rare to find the input shaft the right size too.

We've also made driveshafts to fit different makes of cars starting from scratch. Say, for instance, a Ford transmission mated to a Chevy axle. We cut both shafts off right to the steel flanges for the universals, then installed the transmission end into the tailshaft all the way, pulled it out 2" and measured between the universal joint caps. Using a new driveshaft tube cut to the right length, install the flanges into both ends, index the u-joints and weld them up. It gets real tricky when they are different diameters.

When you're done, you'll have a custom driveshaft at a fraction of the cost of having one specially made.

Have I confused you yet?

OverlandZJ

How could the shaft be short if they both came from a stock 242 equipped vehicle?

It's not supposed to bottom out within the transfercase.

dave1123

They didn't. The jeep originally came with a 249. The 249 and 242 are not the same length. Also throw into the mix the V8s have a D44a rear axle and the 6s have a D35 which have different size u-joints. ALSO I think this is a export jeep, so anything goes! The only clues I have are he said "round about" and "driveline"

Full Stock Jeepy

a machine shop shop seems to be my only option, so i'll have to make some calls around to see what any of the 15 or so shops i googled can do.

I'm from the states by the way. I live up in Washington state and round abouts are slowly making there way into our roads. i love them, they are so much more efficient than a 4 way stop.

dave1123

You're right. They are the UK's answer to ANY major intersection, even the Motorways! They take up less real estate than an interchange. My wife and I took a tour of the UK and I got a rental (hired) vehicle and did the driving. It took me a while to get used to blasting into a roundabout and turning LEFT! Scary to say the least! The first one I hit on the A40, I went around the full circle while she was looking for our exit. My wife wanted to go to her family's home town, but they wouldn't let us take the hired car to northern Ireland.

Sorry to peg you as a Brit! We get a lot of them on the forum.

Getting back to your driveshaft. AFAIK, the 242 was used in 4.0 ZJ jeeps almost exclusively while some 4.0 and all the 5.2 and 5.9 Limited ZJs used the 249. The V8s also used the D44a rear axle while the 4.0s used the D35. The D44a uses a larger u-joint than the D35. The bearing caps are the same, but the cross-X is bigger. The 4.0 and the V8s use a different transmission as well, that's why I found it amazing that you found a 242 that you didn't have to swap the input shaft on. The smaller u-joint has a 3.218" snap-ring to snap-ring span and the larger one has a 3.625" snap-ring span. The rear axle yoke has 2 little tangs on it that the joint caps have to fit between. You've got to measure all this stuff to see what you've got before you start cutting anything. Someone mentioned they make an adapter u-joint with the smaller span on 2 caps and the larger on the other 2, but I don't see this happening because the dynamics of the joint in motion with 2 different dimensions would tear it apart.

Full Stock Jeepy

no kidding right. I was dreading the pry job i would have to do on the transfer case if they were different sizes, but i was either lucky, or pulled it in the year range where the inputs are all the same. It does seem odd for the straight 6s to have the better of the 3 transfer cases. You know, a v8 242 factory option would make this a whole lot easier.

here i though roundabouts were a bit more mainstream, but i guess i don't travel enough

dave1123

Well, at one time, The original purchaser could have a jeep built any way he wanted it, so anything is possible. It's entirely possible to find a ZJ with a manual transmission, but don't hold your breath!

The first time I saw a traffic circle or roundabout was in 1957 and it was at the junction of US route 1 and US route 20 on the west side of Boston. Now they have a circumferal highway called I128.

Full Stock Jeepy

picked up a perfect 33 1/2 inch drive line off a 97 grand cherokee at the junk yard with a 4.0L and 249 transfer case, who would of thought.

dave1123

Ya see? Sometimes you luck out!