4.0 or 4.0 with AW4?

So I picked up a '99 with a blown 4.0. PO says that the tranny and Tcase are relatively new and were operating great before the engine went. i've been asking around about 4.0s to pick up and have gotten a really good response from members in the area. I've got two options i'm choosing from. Do I want just the 4.0 and pay less and just bolt into my existing AW4? Or do I want to pick up a 4.0 that is already bolted up to an AW4 and just drop my existing tranny and throw the whole donor package in? I suppose that my real question is whether it is more difficult to mate the engine to the tranny if the tranny is still in the jeep, rather, is it easier to just throw engine in tranny in at once instead of hooking one to the other once already mounted? I've never done an engine or tranny swap before, need some advice.

Thanks,

ECGTECH

If the PO says the existing Aw4 is in good shape, why spend the extra green to replace it with one already attached to a 4.0?

I have heard that it is indeed easier to drop the engine and mounted tranny in all at once, but if you are going to be doing the work yourself, you will probably pull the dead engine and tranny out as one package, then you can transfer the AW4 to the donor and drop the whole deal right back in.

What's 'blown' on the current engine? anymore detail from the PO? it's not easy to kill a 4.0. (comparatively i guess!)

It'll be a little more difficult to get the tranny and engine connected in the vehicle, but not too bad - most people having difficulty lining the two up are doing it the wrong way (bolting the torque converter to the engine and then stabbing it into the transmission.)

However, what's stopping you from pulling the transfer case and transmission currently in the XJ out, bolting them to the engine, and then putting them back in as a unit? That's what I'd do if I was questioning my ability to bolt the two together in the vehicle.

IMO, it comes down to how much you're paying. If you can get the whole engine/tranny and/or transfer case for only a little more than the engine, I say buy the whole thing and keep the transmission/transfer case as spares.

Once the engine is out, getting the transmission and transfer case out as a unit is easy - the only things holding them in are the transmission crossmember, the driveshafts, and some wiring and shift cables and breather+cooler hoses. Also, a transmission and transfer case linked together aren't all that hard to pick up, I think they only weigh like 180 or so combined. A standard rolling floor jack is easily strong enough to lower the package down and slide it out if you have the vehicle on a lift or jackstands.

I have done quite a few XJ motor swaps and IMO it is really pretty easy to swap in the motor while the tranny and t-case are still in the vehicle. One thing to note is the E12 reverse torx on the top of the tranny...there are 2 of them and it you try a regular socket on them you will screw them up and then it will be a royal PIA to get out. When pulling the motor take the time to pull the radiator, tranny cooler, fromt header panel etc and get all of that out of your way and it is smooth sailing from there.