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aw4 p0740

Old May 3, 2014 | 02:27 PM
  #1  
Tango1's Avatar
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Default aw4 p0740

Finally Cured my no lockup problem.
The original conditions: started getting bad mpg and cel came on. Lockup would happen in first 20 min of driving then stop. No reverse lights and no start in park occasionally.
Method of attack: cleaned nss fist. Got reverse lights back but no lockup condition continued. Adjusted tv cable. No change.
Adjusted brake light switch. Cured problem for 2 days Then no lockup at all. Replaced brake light switch. Lockup became intermittent. Some days had it all day. Other days would quit after 20 min or so.
Pulled all electrical conections to tranny. Cleaned greased and reconected. No problems for 2 weeks now!
I have other problems that lead me to believe it was electrical. The dash quits once in a while. A good thump and it works again.and electric fan connection was corroded as well.
So if your having hard to diagnose problems overdrive lockup. Check the connections.mine was a combo problem of brake light switch and dirty connections. Tango1
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Old May 3, 2014 | 06:37 PM
  #2  
CCKen's Avatar
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Joined: Aug 2010
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From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
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Originally Posted by Tango1
Finally Cured my no lockup problem.
The original conditions: started getting bad mpg and cel came on. Lockup would happen in first 20 min of driving then stop. No reverse lights and no start in park occasionally.
Method of attack: cleaned nss fist. Got reverse lights back but no lockup condition continued. Adjusted tv cable. No change.
Adjusted brake light switch. Cured problem for 2 days Then no lockup at all. Replaced brake light switch. Lockup became intermittent. Some days had it all day. Other days would quit after 20 min or so.
Pulled all electrical conections to tranny. Cleaned greased and reconected. No problems for 2 weeks now!
I have other problems that lead me to believe it was electrical. The dash quits once in a while. A good thump and it works again.and electric fan connection was corroded as well.
So if your having hard to diagnose problems overdrive lockup. Check the connections.mine was a combo problem of brake light switch and dirty connections. Tango1
Thanks for the good follow up Tango1.

BTW: Tango1 sounds like a military call sign. Is it?
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Old May 3, 2014 | 09:42 PM
  #3  
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Nuclear Security Response Team. Subcontract for the DOE through SCIS.
Tango1
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Old Oct 7, 2015 | 01:26 PM
  #4  
cpefy3's Avatar
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Joined: Oct 2010
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From: Chicago, IL
Year: 1998
Model: Cherokee
Engine: 4.0
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Are you still locking up consistently? If so can you be specific on the connections you cleaned and lubricated. I have a 98 that is also not locking up after a little bit, and sounds very similar to yours.
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Old Oct 7, 2015 | 05:33 PM
  #5  
cruiser54's Avatar
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
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Originally Posted by Tango1
Finally Cured my no lockup problem.
The original conditions: started getting bad mpg and cel came on. Lockup would happen in first 20 min of driving then stop. No reverse lights and no start in park occasionally.
Method of attack: cleaned nss fist. Got reverse lights back but no lockup condition continued. Adjusted tv cable. No change.
Adjusted brake light switch. Cured problem for 2 days Then no lockup at all. Replaced brake light switch. Lockup became intermittent. Some days had it all day. Other days would quit after 20 min or so.
Pulled all electrical conections to tranny. Cleaned greased and reconected. No problems for 2 weeks now!
I have other problems that lead me to believe it was electrical. The dash quits once in a while. A good thump and it works again.and electric fan connection was corroded as well.
So if your having hard to diagnose problems overdrive lockup. Check the connections.mine was a combo problem of brake light switch and dirty connections. Tango1
Good job. Cleaning those connectors has worked so well for me that I wrote this a few years back:

Cruiser’s Trans Plug Refreshing


Over near the transmission dipstick tube are 2 rather large connectors. One is black and the other gray. These 2 connectors carry all the info between TPS, TCU, NSS, speed sensor, and transmission solenoids.
Unplug each one, visually inspect for corrosion or bent pins, spray them out with electrical contact cleaner and plug them back in.


Additionally, if your Jeep is an 87 to 90 Renix, it’s always a good idea to reach up under the glovebox area and unplug the connector to the TCU and spray it out along with the receptacle of the TCU. While you’re there, find the fuse right in that area for the TCU. Remove it and spray out it’s receptacle and clean any corrosion from the fuse.

Revised 9-10-2012
Attached Thumbnails aw4 p0740-trans-plugs.jpg  
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