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D35 -> D44 swap: Modify D35 drive shaft?

mhead

NAXJA Forum User
Location
Encinitas, CA
I've a 1992 XJ I6 Auto with a NP 231 transfer case. There is no lift in the back save what comes from heavy duty leaf springs. I have 1" pads under the front coils.

I've replaced my D35 with a D44. I have read on NAXJA that I should shorten the drive shaft. But I don't know by how much.

How much should I take off? Asked another way: What should the distance from the end of the NP231 housing to the center of the yoke UJ cradle be for a stock XJ with a NP231? I'm a stupid ninny since I didn't make this measurement before I swapped. Things woud be so much easier if I had.

One other question: the D35 had no shims between the leafs and the spring perches. Will I have to add any to get the driveline angle correct on the D44?

Thanks!
 
The snout on a D44 is about an inch longer than the D35 you replaced. You may get lucky and the old shaft be short enough. I've seen them both ways. Just install it and then see how much room you have left on the slip yoke. Look at the angle the drive shaft is at and visualize the axle moving up as it would when you hit a bump. You have to have enough movement in the slip yoke to allow that deflection.

You can calculate the amount needed by measuring the angle and then the driveshaft length. Get out your high school geometry books and go to town.
 
The difference between a D35 driveshaft and an 8.25 driveshaft is 5/8". I've been told that the 8.25 has about the same snout depth as the D44, so you should be shortening about that much.

However, rather than chop a perfectly good driveshaft, this might be a good time to invest the money that would cost you in a budget boost. A small lift and extended bump stops and that "longer" driveshaft will be just right. There's no sense chopping it if a year from now you're going to need it longer again.
 
Looks like the 5/8" estimate is a good one. Right now (D44 in place of D35 but no mod to driveshaft used with D35) I have 0.9" from the end of the transfer case to the shoulder (where the next larger diameter on the yoke edge is) on the yoke. I drove around last night looking for old XJ's in parking lots. I managed to find 3 that were similar age to mine. I crawled under and made the same measurement. I measured 1.51, 1.54, and 1.55. So this gives about .6 as the amount more that my yoke should be out. Same as 5/8"!

So while everyone else was preoccupied with the election, I was crawling under Jeeps in parking lots. Who got the best deal?
 
mhead said:
Looks like the 5/8" estimate is a good one. Right now (D44 in place of D35 but no mod to driveshaft used with D35) I have 0.9" from the end of the transfer case to the shoulder (where the next larger diameter on the yoke edge is) on the yoke. I drove around last night looking for old XJ's in parking lots. I managed to find 3 that were similar age to mine. I crawled under and made the same measurement. I measured 1.51, 1.54, and 1.55. So this gives about .6 as the amount more that my yoke should be out. Same as 5/8"!

So while everyone else was preoccupied with the election, I was crawling under Jeeps in parking lots. Who got the best deal?

Thanks funny man. Your lucking the owners didn't see that and think you were going to steal their vehicles. I'd go with a 3" lift like was said or a cheap 2" budget boost and your driveshaft will be fine. For the same amount of $ or more, you will shorten the driveshaft and still have a stock height vehicle. A 2-4" lift does wonders to the looks of an xj and doesn't cost that much to do because your track bar, controls arms, etc will still be o.k. to use.
 
It is a common misconception that a lift requires a longer drive shaft. Just remember, if you push the axle up when you hit a bump, lift or not, the differential goes in the same place so if the shaft is too long with no lift, it will be too long with a lift if you hit a bump. Now that is said, if you add bump stops and keep the axle from moving up to much, that can prevent the shaft from binding and you can get away with a longer shaft.

With a lift, what you need is a shaft that can extend further. That is why good quality offroad shafts have a longer set of splines in the slip section.
 
With the BA/10, 231 t-case, and 3" lift I was suprised to find that my old shaft just barely fit with the new D44 rear end fully drooped. There was no way it would have worked. I took the opportunity to get a HD SYE and new driveshaft. Not cheap, but if you have the money, its a good investment.

Travis
 
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