Torqueflight 727 differences

[Milktruck]

Hey everyone!

Got serious about my "pour through" transmission and took the beast to a shop. Needed a rebuild, but opted to grab a used unit and have it sealed and installed, but I've run into a mismatch issue. Hoping that there is some insight lurking out there.

The unit that was in my '88 used a flex plate, and the unit I picked up (sans torque converter) uses a different torque convertor and apparently a "flywheel" for the starter. I'm kinda stuck on how to move forward. The "new" unit came out of an '89 Grand Wagoneer IIRC and is NOT a "lock-up" unit from an earlier model year.

Any thoughts about how to get this on track would be helpful. I see a few ways forward, but would love to hear what others think.

[Stuka]

Do you have a photo by chance? I have never heard of a 727 automatic with a flywheel, they all use flex plates. The flex plate is specific to the displacement of the engine it came from though. So a flex plate from a 401 cannot be used on a 360. So you are best off using the flex plate on your current engine and just mount the new trans/TC to that.

[REDONE]

What side is your starter bulge on? I'm thinking that what you were told is a Jeep 727 might not be a Jeep 727.
Chrysler:


Jeep:


International Harvester:


Images borrowed from this thread on forabodiesonly.com
https://www.forabodiesonly.com/mopar/th ... ze.387904/

[Milktruck]

Got it ID'd

It's a 36RH - P/N 4531025 for a 1990 model year SJ. The P/N is: pk4531025 0401 - but I'm guessing that the 0401 specifies that the unit was spec'd for a 401 not a 360 like mine.

Can anyone confirm? And if so, do I need to start over or just pick up the right flex plate/torque converter?


Thanks!

[REDONE]

The AMC 401 went out of production in 1978, so if that transmission is for a 90 SJ, that 401 in the part number means something else.

[tgreese]

According to the '87-90 parts book here, https://oljeep.com/edge_parts_man.html 4531025 is correct for a 1990 SJ Jeep. No evidence of the "pk" or "0401" numbers in that book. Flexplate and torque converter should be in that book too, if you'd like to dig in to it.

As mentioned above, the 401 was gone from the Jeep line after the 1978 model year, and never appeared in a Jeep with the Chryco transmissions.

[Milktruck]

Thank you redone - didn't even cross my mind on that. So I think I need to go get a look at it to get a better understanding. This is the first time I've taken an old vehicle to a shop (other than alignments and mufflers) in about 15 years. It bugs me that I'm not on the same page as the person doing the work.

It was my understanding going into this that a 727 would bolt up. It has been verified to have been pulled from a '90 Grand Wagoneer and I've crossed that with the P/N stamped on the driver's side pan rail. I didn't even think to go after the flex plate/torque converter which is my error.

[will e]

At some point I think they added a locking torque converter to the our Jeep 727's but someone will verify that for me.

[dodgerammit]

Lockup TC was in the very early 80s. FWIW, my 84 is non-lockup. The difference will be in the input shaft of the transmission. Lockup input shaft splines will stop about 5/8" from the end with the end being stepped down and smooth. Non lockup shaft splines will run all the way to the end. Maybe 1/8" of bevel on end will not have splines.

Scroll down to reply #5 for the images showing the difference: https://ramchargercentral.com/vehicle-h ... converter/

Other than that, if they are AMC bolt pattern, and your rig has the AMC 360, they should bolt up.
If the Trans shop is giving you a run around with some BS about a flywheel, etc, find a different shop.
We've all been there with mechanics that don't know AMC and try to sell you something you don't need.

[dodgerammit]

Also, the TC is neutral balanced. No ring gear. Ring gear is on flexplate as mentioned and flexplate is balanced to rotating assembly of motor.

[dodgerammit]

BJ's off road has the flexplates available new. The year split for the 360 is 87/88, so that could have something to do with it.
They also list 401 applications from 1980-87. I'd verify your engine and see what it is should you need a new flexplate.
Otherwise, if your flexplate of your engine is good you keep it and use it with the new transmission.

[Milktruck]

I appreciate the responses. It is beginning to feel that this might be a shop issue, not compatibility.

[Dr.Bob]

FWIW, the usual TF727 used in Mopars had the ring-gear teeth on the torque-converter, not the flexplate, while the AMC version has them on the flexplate and not the torque-converter.

Is part of the confusion from him assuming the AMC setup would be like the Chrysler setup?

[Milktruck]

Welp, seems the mystery has been solved...

It was a shop issue, but not the type to get twisted up about. Seems when I dropped off the transmission/transfer case one of the shop hands threw another customer's torque converter on the shelf with it. They've been looking for that TC and arguing with the other customer about whether he gave it to them, all the while telling me that the torque converter doesn't fit my application. SMH

It got real quiet when I said "I didn't bring you a torque converter, I brought you a naked transmission", then about 10 secs later I could almost hear the lightbulb switch on.... I think we're back on track.

Thank you everyone for the quick and clear responses. This list has helped me many times.

[Stuka]

Welp, seems the mystery has been solved...

It was a shop issue, but not the type to get twisted up about. Seems when I dropped off the transmission/transfer case one of the shop hands threw another customer's torque converter on the shelf with it. They've been looking for that TC and arguing with the other customer about whether he gave it to them, all the while telling me that the torque converter doesn't fit my application. SMH

It got real quiet when I said "I didn't bring you a torque converter, I brought you a naked transmission", then about 10 secs later I could almost hear the lightbulb switch on.... I think we're back on track.

Thank you everyone for the quick and clear responses. This list has helped me many times.

Oh boy, feel bad for the guy that did that. But at least you, and the other customer, got sorted out.

[dodgerammit]

Good news!

[tgreese]

Glad for you. Thanks for the interesting story!

[Georgie]

So just caught this thread. I’m getting a crazy metallic squeal from my trans and have been told it’s the clutches going out. Got quotes $1500 by a shop to rebuild the transmission after I remove it. Needless to say looking for a used unit. I have a 1985 GW will any trans from a GW from 1985 on work? Thanks for the help.

[bigun]

So just caught this thread. I’m getting a crazy metallic squeal from my trans and have been told it’s the clutches going out. Got quotes $1500 by a shop to rebuild the transmission after I remove it. Needless to say looking for a used unit. I have a 1985 GW will any trans from a GW from 1985 on work? Thanks for the help.

How mechanically handy are you, a rebuild kit is inexpensive, get the book a very clean place to work rebuild it yourself