middle of resto...transmission problem...

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SouthernLatitudes
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Joined: Mon Oct 22, 2018 7:30 am

middle of resto...transmission problem...

Post by SouthernLatitudes »

in the middle of a restoration of a 1988 grand wagoneer. The engine has been rebuilt and runs nice and smooth. I put the trans black in and it failed to engage at all. when I removed it, the torque converter was stuck/welded to the pump. it is out now and I've been in contact with transmission parts supplier that is trying to get me headed in the right direction.

the number of splines on the input shaft (24) tell me that it requires a non lockup torque converter, which I have ordered and test fit. I removed the pump and there is a group of three check balls on the back of the pump that tells me that it is a lockup pump.

was there a lockup/nonlockup option on the 727 transmission in 1988? anybody have some insight?

I am guessing that someone has been in here and gone off book with a repair...
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Stuka
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Re: middle of resto...transmission problem...

Post by Stuka »

There has been a lot of discussion over the years regarding lockup and non-lockup converters on the 727 in FSJs. As I recall there is no way to know what each Jeep has unless you look. AMC typically took whatever was available, so its not unusual to find parts that came on the vehicle from the factory, but do not match parts books for a specific year.

If it looks like yours needs a lockup converter, I don't think that will surprise anybody here. But perhaps somebody here will have some hard info.
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candymancan
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Re: middle of resto...transmission problem...

Post by candymancan »

You can tell when a torque convertor locks up rpms drop significantly.. Mine doesnt. So i highely doubt wagoneers ever had that.. but i heard stories they did.. But thats just me maybe im wrong..
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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Stuka
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Re: middle of resto...transmission problem...

Post by Stuka »

candymancan wrote:You can tell when a torque convertor locks up rpms drop significantly.. Mine doesnt. So i highely doubt wagoneers ever had that.. but i heard stories they did.. But thats just me maybe im wrong..
We have definitely had people go to rebuild their transmissions and come across locking converters. The RPM drop is only about 50rpm as I recall, happens at something like 40-50mph as I recall.
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Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
SouthernLatitudes
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Joined: Mon Oct 22, 2018 7:30 am

Re: middle of resto...transmission problem...

Post by SouthernLatitudes »

Thank you for your help w activation and for the response.

Since the input shaft, that terminates into the back of the tranny, is splined for nonlockup, I’m more apt to guess that the lockup pump is the inconsistency, not the torque converter...

I rebuilt the motor, that made sense to me. This is my first time messing with the guts of a transmission.
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Stuka
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Re: middle of resto...transmission problem...

Post by Stuka »

Yeah, the input shaft is different for lockup vs non-lockup. If its splined for a non-lockup, a lockup won't even fit to my knowledge.
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candymancan
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Re: middle of resto...transmission problem...

Post by candymancan »

Hmmm rpm drop on my zj in 3rd gear with od off us small as well but noticable.. drops like 500 in overdrive.

Ill have to check my tach then more closely and see if it drops or not thx
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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