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91 4.0 Auto 2Wd To 4Wd???

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You're on the right track... and yes, the 2wd trans CAN have the pieces swapped to mate up a transfer case to it... BUT....


You're going to need a 4wd output housing to swap on (the part on the back of the trans that the t-case bolts to) AND a 4wd output shaft because the 2wd one is longer. To change the output housing and the tail shaft, you have to almost completely disassemble the transmission. So, unless you have a junk 4wd transmission laying around to scavenge the parts, have the know-how and tools to tear apart and rebuild a transmission, and don't mind getting your hands dirty.... you're better off finding a good used 4wd unit to swap in. They're a dime-a-dozen in wrecking yards, and you can most likely get one out of the same rig you'll take the transfer case, front axle, linkages, etc from.


You'll need to match the output spline of the trans you choose to the input spline on the t-case... 87-90 AW4's and 231 t-cases are generally 21 spline, while 91 and later are generally 23 spline... though things change a bit on the newer XJ's and I'm not familiar with those.

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if it is a auto trans all you haft to do is swap out the tail housing bolt up the t case and your gtg there is nothing internaly differnt between the 2wd and 4wd


Uhm, yes. Yes there is.


The 2wd output shafts are considerably longer than the 4wd ones, as they need provisions for the speedometer gears. I know some people on here have been able to cut down a BA 10/5's output for a T-case, but it's a good amount of work, especially for a relatively junk transmission.

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Yeah, it's all the same... the only difference is the rear driveline length. I used parts from a donor 88 Cherokee to do the 4wd swap in mine... trans, transfercase, front axle, driveline, etc. It was a bolt-in deal.


The 2wd AW4 is the same in the XJ's as it is in the MJ's... so there's no reason it would be any more difficult.

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