Pulling the Engine - Torque Converter first, why?

[nwoods]

I need to pull the 3.5L from my Gen 3, and my motor is seized. The Internet told me that I need to remove the bolts holding the torque converter to the flex plate before separating the tranny from the engine "or bad things might happen".

However, because the engine is seized, I can't turn the crank to get to the torque converter bolts. It has been suggested that I remove the oil pan and remove the pistons and rods and try to free up the crank from beneath, but doing that means disassembling the front diff, exhaust system, and crossbars. It sounds a lot like performing rectal dentistry.

Watching a bunch of youtube videos (because 100% of my mechanical knowledge has been gleaned this way so far), I'm just not seeing the need to remove the torque converter bolts before separating the engine from the transmission. It looks like these two elements (engine and tranny) are just slip fit together over the input shaft from the tranny into the torque converter.

What am I missing? I assume I can get the engine out a whole heck of a lot easier if I don't have to dissemble the entire car to do it. Once the engine is out, I can then flip it over on a stand and work on the oil pan, remove the pistons, free the crank, and THEN unbolt the torque converter.. Or just buy a new one and toss out the old with the engine block.

What I am not understanding? Anyone do it this way? Any pitfalls?

 

[normal_dave]

I'll give a general explanation from my old-school Chrysler point of view. (I haven't had to pull my Mitsubishi engines yet). The transmission has concentric input shaft(s) with splines that mate to the inside of the torque converter. The length of the shaft is basically the distance from the front edge of the transmission pan to the front edge of the torque converter on the engine side. Picture a centerline on a drawing from the front of the engine through the crankshaft, torque converter, input shaft, transmission. That centerline has to be "perfectly" aligned like the dockup on Apollo 13.

If you try to separate the transmission from the engine in the car, with the torque converter still attached, you have to be able to perfectly separate the two along that linear line, until the input shaft clears the torque converter, allowing the engine to be lifted up and out. While I haven't tried it on the Montero, on the much easier older Chrysler V8s, I would say "fat chance" of making that happen inside the vehicle. The one time I had to do what you are doing, (on the old Mopar), it was out of the vehicle, and on the ground. I had to pull the V8 transmission loose from the engine, leaving the torque converter attached to the engine. It was a small V8 engine and transmission, but it was a bear, getting everything straight so I could pull the transmission loose along that "line". I have often pulled engine and transmission together and separated them later, with the engine able to turn, removed torque converter bolts and game on. The transmission acts as a counterweight of sorts, making the engine tilt a bit easier to clear the radiator mounting area. I'll wait for the experienced Monty folks to chime in on that one.

The flex plate bolts to the face of the torque converter. The nose of the torque converter doesn't really "connect" to the crankshaft, it just mates up, the flex plate does the work of connecting the converter to the crankshaft. That's why you want to separate it there if you want to leave the transmission in the car. You only need an inch or so of separation clearance between engine and transmission to be able to start to pull the engine. You would also risk damaging the front pump seal on the trans, and maybe the internals of the torque converter as well. The neck or snout of the converter has two slots that engage the gear pump inside the transmission, You might crack, break, bean the converter snout as well in this process, with the engine weight and transmission weight on either end and the converter snout bearing the load and being the pivot point.

Hey, I really do write too much in posts...

 

[Salonika]

Man you are in a bad situation.....I don’t remember how much extra space there was when I did my motor rebuild, but I feel like trying to get the motor out without unbolting the TC would be very difficult and risks damaging the input shaft to the transmission.....not sure. The TC slides onto the tranny input shaft at least a few inches so as Normal Dave said, it’s like undocking from the space station. I think it could be done but man, if you didn’t pull it perfectly straight, it might bind pretty bad. I think I’d go after the pistons. I might try once to slide it out, but if I encountered any difficulty, I’d change the plan. And even if you could slide it off, it might pose clearance problems for pulling it up and out anyway.

 

[Salonika]

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2534166/Re:_Pull_Engine_Torque_Convert

Good info there. A few quick Google searches has me leaning towards likely trans damage if you try to pull it with TC attached (front pump, seal and bushing would be damaged leading to a tranny project). I’d go after the pistons via oil pan.

 

[jeep-N-montero]

Is pulling the engine/trans together and separating out of the vehicle not an option?

 

[Toasty]

I had a TC stick to a flex plate a couple times and the TC had to come out with the engine. It's not as hard as it is messy, once you clear the bell housing you tip the motor back and dump all the oil in the TC on your garage floor. It's not easy to snake the engine outnof the bay with TC attached, prepare your favorite words.

 

[nwoods]

Is pulling the engine/trans together and separating out of the vehicle not an option?

If a mechanic where willing to help me, that would be an option. Currently, its way above my skillset.

 

[jeep-N-montero]

Or just sell it off and buy that sweet 2006 that just popped up on the fb page.

 

[offthepath]

I'm not 100 percent sure that dropping the diff would give you access to the oil pan. The entire sub frame may be in the way still. I'm pulling my diff this weekend and will see what it looks like.

 

[nwoods]

As it happens, removing the engine while leaving the torque converter in place was faily easy. With the radiator out, plenty of room to slide the engine forward and out

 

[Salonika]

No problems prying the two apart?

 

[coffeegoat]

Good on you Nwoods - I always like the contrarian approach of "well, seems like it should work" in the face of overwhelming opposition.

Best of luck on the rest of the rebuild.

 

[nwoods]

No problems prying the two apart?

No, once we found the three additional bolts near the starter and under the catalytic converter, it came apart pretty easily. I did have to remove the engine mounts rather than lift the engine off the engine mount studs. But doing so allowed me to pull the motor forward to clear the tranny housing. I also had to remove several transmission oil cooler line brackets that were attached to the engine block in various locations.

 

[nwoods]

Adding photos for those interested:

 

[Salonika]

Let us know when you find what was seized up. Love the instashade tent, it looks like it was hot.
Remember when you put the motor back in, when you place the torque converter back on the trans, rotate it around until it slides “all the way” on. I put mine on, and it looked good, I thought it was on all the way but once i got the motor mated up I could not tighten all the bell housing bolts. I took the motor in and out like 5 times trying to figure out why it wouldn’t work. A friend reached in there, spun the TC a little and it popped onto the shaft another 3/4”. It went right together after that. Just make sure the TC is all the way seated on the shaft!