Got the 727 out, some questions?

[Strode182]

In the continuing quest to tear my Cherokee down into as many pieces as possible, I've now pulled the transmission.
I've never messed with automatic transmissions before, so I have some questions:

1) Is there a bottom cover for the transmission and flexplate? Mine was open towards the front. Is something missing a cover or is that how it's supposed to be?

2) Is the flexplate indexed to the crank for balance? The flexplate has a weight welded to it. Does it just go back on, or does it have to be clocked to the crank at a certain position? I sprayed paint on it just in case....

3) There is no pilot bearing, right? The nub on the TC is worn. Does it ride on something in the crank, or does it just bolt to the flexplate?

4) I can't find anything in the TSM about the TC. Do I just leave the fluid in it and set it aside? Should I just assume the TC is good, or is it wise to get a new one since I've gone this far? It's a lockup model and I did a quick search at Summit and I don't see them for sale.

My Cherokee only has 66K miles on it, and I'll replace the TC if it's wise to do it while I have it out. The front seal is great, the rear seal is great, it was just leaking from the pan and the shift nub-thingy.

Thanks

[derf]

1. Yes. There is supposed to be a cover.

2. Yes, the flex plate is indexed. The bolt pattern will only fit one way. When you go to put it back on, try it in different rotations. You'll see that the bolt holes don't line up until you get it back on the way it came off.

3. Right. The nub on the TC rests against the crank flange

4. If it wasn't causing any trouble you don't have to replace it. Leaking seals don't usually cause any problems with the TC. If you really need a replacement, a transmission shop should should be able to find one for you.

[Strode182]

Originally Posted by derf

1. Yes. There is supposed to be a cover.

2. Yes, the flex plate is indexed. The bolt pattern will only fit one way. When you go to put it back on, try it in different rotations. You'll see that the bolt holes don't line up until you get it back on the way it came off.

3. Right. The nub on the TC rests against the crank flange

4. If it wasn't causing any trouble you don't have to replace it. Leaking seals don't usually cause any problems with the TC. If you really need a replacement, a transmission shop should should be able to find one for you.

Thanks.
Now that I think about it, 3 was really a stupid question. It's not like a pilot bearing at all, because it's all fixed together. Duh.

So the flex plate is indexed to the crank, and the TC is indexed to the flex plate too, right? There's only one way to bolt the TC to the flex plate too, right?

[billyj7175]

If it were me, unless the TC is fairly recent, I'd replace it while you have it torn apart.

One of those "since you've gone this far, you might as well replace XXXX as well". Beware though....that line of thinking can and will thin your wallet and multiply project length exponentially...(coming from the guy who intended on just doing a cam/4bbl swap, who is now going on over a year with a garage that looks like a Jeep exploded in it...)

[tgreese]

Front seal is another one of those might-as-wells.

[Strode182]

Originally Posted by billyj7175

If it were me, unless the TC is fairly recent, I'd replace it while you have it torn apart.

One of those "since you've gone this far, you might as well replace XXXX as well". Beware though....that line of thinking can and will thin your wallet and multiply project length exponentially...(coming from the guy who intended on just doing a cam/4bbl swap, who is now going on over a year with a garage that looks like a Jeep exploded in it...)

That's usually my way of thinking, exactly. I only want to do this stuff once.

[Strode182]

Originally Posted by tgreese

Front seal is another one of those might-as-wells.

I'm torn about that, because the front/rear seals aren't even weeping.

I rebuilt my 208, and ordered a full kit from Drivetrain Inc (I think). When I got it, all the bearings and seals were Chinese. I ended up just fixing what was busted and reusing my American made Timkens and seals that were in it, because I didn't think the new Chinese stuff was an upgrade.

[derf]

Originally Posted by Strode182

Thanks.
Now that I think about it, 3 was really a stupid question. It's not like a pilot bearing at all, because it's all fixed together. Duh.

So the flex plate is indexed to the crank, and the TC is indexed to the flex plate too, right? There's only one way to bolt the TC to the flex plate too, right?

On the TF727 I think so. I helped with a 727 removal and reinstallation and we had to take it back apart because the bolts didn't line up with the torque converter. We tried to spin the converter but the balance weight was in the way and wouldn't let us spin it around.

Though I do believe that the TH400 has a symmetrical pattern so it doesn't matter which orientation you have.

Either way, the torque converter is neutrally balanced so as long as the bolts line up you're good.

[jaber]

Napa can get you good ones. A seal is usually under $5 and here in the desert, they get hard fast. I always replace them, in most cases, its the reason I messing with it in the first place.

[Carnuck]

Pic of converter neck? Sometimes things look good to a newb, but they are fubar looking for a place to happen!

[FSJ Guy]

X2 (or more) on replacing the torque converter (unless it's known to be new) and the front seal. If you have to replace them down the road, you MUST remove the engine or the transmission, neither of which is fun to do. There's no reason to foul up a nice transmission rebuild by trying to save $80 and not get a new torque converter. Same with the seals. They may be great now, but changing them out now is smart.

As already mentioned, the flex plate is indexed and only goes on one way.

And the flexplate will only bolt to the torque converter ONE way and once you have the engine and transmission mated together, you CANNOT turn the torque converter to "re-align" it if you get it wrong. The counter weights get in the way. Matchmark it (I use spraypaint) and align it BEFORE you mate the two together.

And don't forget the flat metal plate that goes between the engine and the flexplate that mounts to the engine. (The plate with the big hole for the starter) If you forget that plate and drop the engine into the engine bay, you will have to pull it out again because there is no easy way to insert it with the flexplate installed. AMHIK.

[ROK360]

One thing I did when I had my 727 out last year (engine changeover) was tap the top of the case for a breather this also means you need to weld up the original breather hole behind the TC. Seems like good insurance if you you ever intend on doing some water crossings.

Cheers

[Strode182]

Originally Posted by Carnuck

Pic of converter neck? Sometimes things look good to a newb, but they are fubar looking for a place to happen!

There is some dog-leg wear on it....and some heat and metal transfer...whaddya think?

[Strode182]

Originally Posted by FSJ Guy

X2 (or more) on replacing the torque converter (unless it's known to be new) and the front seal. If you have to replace them down the road, you MUST remove the engine or the transmission, neither of which is fun to do. There's no reason to foul up a nice transmission rebuild by trying to save $80 and not get a new torque converter. Same with the seals. They may be great now, but changing them out now is smart.

As already mentioned, the flex plate is indexed and only goes on one way.

And the flexplate will only bolt to the torque converter ONE way and once you have the engine and transmission mated together, you CANNOT turn the torque converter to "re-align" it if you get it wrong. The counter weights get in the way. Matchmark it (I use spraypaint) and align it BEFORE you mate the two together.

And don't forget the flat metal plate that goes between the engine and the flexplate that mounts to the engine. (The plate with the big hole for the starter) If you forget that plate and drop the engine into the engine bay, you will have to pull it out again because there is no easy way to insert it with the flexplate installed. AMHIK.

I'll replace it if it's wise to do it. Where can you find them for $80? I couldn't find them on RockAuto, and I did find one at NAPA for $166.

While we're on it: I wasn't going to "rebuild" it, but while it's out, what else should be done to it?
Front & rear seals...any other seals?
Filter, pan gasket
New torque converter
I know I need to replace the seal around the shift knob, that's definitely leaking.
Is it wise to take it someplace for a "freshen up"?

I think this trans is ok, but it's never moved under it's own power for me, so I don't know. You wouldn't think the PO's kid could blow up the engine, the transfer case, and the transmission all in one night

I don't mind spending money now if I might have to spend more later. I'm all ears......

[jaber]

Originally Posted by Strode182

I think this trans is ok, but it's never moved under it's own power for me, so I don't know. You wouldn't think the PO's kid could blow up the engine, the transfer case, and the transmission all in one night

If it was from a kid, I would not be surprised to find they all are junk. I got a J-20 from a "kid" and the only parts still on that truck is the frame (heavily repaired) and the cab ( heavily dented). I had to change out everything else. I've had this truck for about 4 years now and still find mud from the PO.
If you know a good tranny guy that wont jerk you around, have him look at it. My tranny guy only charges $475 for a complete rebuild and that includes a new TC.
Hope I helped...

[Carnuck]

Open the pan (without flipping it over) and see what's inside for junk in the bottom. I set mine on a 12" x 12" by 3" block I had so I could rotate it and access all the bolts before lifting the trans off the pan. I'd add a drain plug while it's out (universal one from parts stores works)