86 MJ trnsmision Question.

OK ,

Here is my question. I am looking at a 86 MJ 2.8 2bbl Auto 4x4 7'' bed with amc 20 rear end. The bell housing on the trans has cracked. The current owner does not know if it is a 904 or a 727. I do not know alot about the early MJ/XJ's. Does anyone out there know if it is a 904 or a 727. I am guessing 904. Also is the bell housing is cracked that means the whole transmission body is shot. In other words the bell housing is not removale?

Thank you for your help


Jason

1993 XJ 4.0 4x4 5speed.

TF 904

Bell housing is intregal with the transmission body on a TF. If bad, and extends into the transmission body, tranny is junk. If a small crack, you could try and stop the crack by drilling a hole just past the end of the crack.

The TF 904 used on a Jeep is not a MOPAR bolt pattern.

Of course that 2.8l is a pile of crap too. I'd keep looking.

If you get the jeep for practically free, then sure! The amc 20 rear end is VERY rare in them, and can be as strong as a d44 with upgraded shafts...

Just swap out the 2.8/tf904 for a 2.5/ax-5 (or 2.5/ax-15 if you can find a dakota with that), and EVERYTHING in the engine compartment, and you'll have a stout, reliable, and efficient run-around/offroad truck! Oh, and grab the interior wiring/hardware (if you want to get rid of the bench) from a matching year XJ, splice it into your lighting harness, and you should be great!

I wouldn't try to get an Aw4 with the 2.5, or any auto for that matter... it's just too much of a dog!

Yes you have a TF904, unles someone has put in a 4 speed 727 but that would requier some extensive modifaction. ANd would be impossible in that the 727 never was produced with the Chevy Small Corprate Bolt Pattern (metric pattern). It could be a th700r out of a 87-90 S 10 pick up. And yes the Stock 2.8L was a POS but if you have it rebuilt with some of the right mods the 2.8L can run good. You also have the 2.8L with the one piece rear main and the bigger valves and better valve springs. THey changed over in mid 1985. WHere is the bellhousing cracked?

The bell housing is cracked right around the passanger side upper bolt hole. I am wondering if it could be welded. The truck had the transmission rebuilt 2 years ago i wonder if the installer over torqued the bolts.

- jason

Tripower389 said:

The bell housing is cracked right around the passanger side upper bolt hole. I am wondering if it could be welded. The truck had the transmission rebuilt 2 years ago i wonder if the installer over torqued the bolts.

- jason

Click to expand...

It's cast aluminum, so I don't know how successful that would be. If it's just cracked around 1 mounting hole, I might be inclined to ignore it as there are a number of other mounting bolts holding it on.

Likely what happened is he didn't have the transmission lined up in the torque convertor and tried to force it on. It never works, but people try it over and over again

Have it welded, I've had numerous bell housings welded over the years with never a problem. It's real common if you buy wrecking yard trannys. I have an AX-15 bell housing that needs to be welded. No big deal, except you need to pull the trans to have it done right.

Likely what happened is he didn't have the transmission lined up in the torque convertor and tried to force it on. It never works, but people try it over and over again
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Watch for cracks around other bolts. Often they aren't happy just cracking one of them.