stupid question.. no flames please

I did a 350 swap into my '88 xj years ago-- in the 90s. I knew nothing about motors back then, and I really didn't do much of the work (my father has a shop and did the actual swap). Regrettably, I learned very little from doing the swap.

Over the years I've done a ton of mechanical work, and have gotten to a fairly competent back-yard mechanic level (I've more or less changed out everything on the front/top of the motor, did a FI conversion, among other things). The Motor I have is an '88 block, with very restrictive heads, and I'm sorely tempted to drop in a chevy zz6 motor-- 407 hp, and the exact same dimensions as my current 350. Should drop in without any problems.

Here's the silly question -- I'm working through the checklist of doing the swap, and realize I know nothing about separating the motor from the tranny. It's a 4l60e. I'm trying to figure out whether I should just pull the entire motor out with the tranny, separate the transmission, and if so, other than just unbolting and propping the transmission up, are there any other issues I should be aware of?

Any thought appreciated.

And by the way.. this is mostly a "for the fun" of it project -- it's not something I need, and I know it. before anyone flames me, I understand that I don't need 407 hp for off roading-- I also understand that I could do it cheaper getting a junk yard motor.

The 4l60e is a decent tranny but I would keep your 700r4 or go with a 4l80e for that much HP on a rig. The 4l60e is basically a 700 with electronics. With the 4l60e you would also need to also pull the ECM for it and get it programmed to work. If you do decide to go with a 4l60/80 you have to make sure it's a 4x4 one and not 2wd. There is also the questions of the tcase and if it will bolt up or if you need an adapter.

Personally, I'd keep the 700r4 just get some new heads, intake manifold, cam and have the ECU reflashed, or build a 383. Unless your going full out and need all 400 horses, a stroker is a hell of a lot more fun on the trail.

smokeyyank said:

Personally, I'd keep the 700r4 just

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Dammit.. got my wires crossed-- I have a 4l80e in another car.. My jeep has a 700r4, and I'm keeping it, not swapping it. my question really is a little more straight forward --


I'm just swapping the motor, keeping the 700r4... is it easier to pull the tranny with the motor (which some people have told me to do, even though I'm not swapping the tranny), or separate the tranny from the motor, and reconnect when I swap the new motor in?
If the latter, which I assume is the case, is there anything special involved in separating the tranny from the motor?

If you have the means to drop the trans with ease, like trans jack, etc. Then it is a simple enough task. Otherwise, pull the engine and trans together if it may be easier.

I gotcha now, I'd pull it, swap it and then bolt it up and drop it back in together. Nothing special, just make sure it's supported, put a catch can underneath for any tranny fluid, unbolt it and should be about it. Make sure the TV cable is disconnected along with any cooling lines.

It is going to depend on what you want to do and how long you want to take.
If you arent in a hurry i say pull them both out. Gives a chance for a good scrubbing of the engine compartment and alot easier to replace seals on the transmission, which should be done while you have easy access to them.

Johnnie Walker said:

If you have the means to drop the trans with ease, like trans jack, etc. Then it is a simple enough task. Otherwise, pull the engine and trans together if it may be easier.

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I have a lift with a hydraulic jack in between the ramps I was going to use to support the trans.

I personally would leave the trans in. I don't think it's any easier to pull everything out at once. The torque converter bolts are super easy to get to on those, it would take Ike 5 min to separate them. I'd recommend doing to the front pump seal while it's apart.

I would also be in the camp that says separate them in the vehicle.

It has been a long time since I separated an auto trans, but I think it is just three bolts around the perimeter of the flexplate, in addition the the bellhousing bolts (6 or is there a 7th one top center?--Chevy vs BOP bolt patterns--been too long).

Make sure you keep the tranny well supported.

Note that the torque converter just slides onto the input shaft of the transmission. This also means that it can be slid off. Easily once the engine is out of its way. A piece of rope/paracord/electrical wire across the face of the bell housing can help prevent an unwanted surprise on that front. If you do choose to slide it off then be aware that it needs to index correctly in order to go all the way back on. Just rotate it around until it slides in that last inch or so.

Keep the trans in the vehicle and just remove the engine. Way easier imo. Please note when installing leave the converter on the trans not the flex plate! Tighten the bellhousing to the block then finess the converter up. Its easy to break the pump if you aren't careful.


Good luck

all very helpful guys.. this is really the only thing holding me up, everything else seems within my experience.