Rebuild VS Replace '99 4.0L in an XJ
I'm at a crossroad with my Jeep where I need to either rebuild or replace the engine.
My 1999 XJ has 275,000 original miles on the engine. 8 hours from completing a 10,000 mile road trip around the US I blew the head gasket and broke something metallic inside, presumably push rods. The engine died without warning while going about 65mph along an interstate, there were no common signs of bad engine voodoo.
I haven't tore down the engine yet but I can only turn the flywheel about 1/4 turn when I hear a metal clunking sounds and then the flywheel stops.
Is it worth rebuilding an engine with that high of mileage or would I be better off getting a crate engine?
Also, should I rebuild the tranny while I'm at it and have the engine out? Will I run into any common problems with a rebuilt or zero time engine mounted to a high mileage tranny? Are there any higher performance or stronger trannies?
How complicated is it to rebuild a tranny?
Does anyone have personal experience and opinions with any of the following crate engines in their jeep (not to be confused about anything you've read or heard someone else talk about ):
If I rebuild, this will be my first rebuild project. Likewise if I do the install, this is the first time I'll be working on a complete engine. I wouldn't say I'm a mechanic by any means, but I can read and follow directions pretty well and do most of my own maintenance.
I appreciate any insight you might have to offer.