Loss of Lockup/OD

J

johnfak

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Joined
May 1, 2011
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253
Hi guys

Anyone know how to diagnose the loss of lockup/OD ??
Apparently this just literally happened whilst the truck was idling (eg working fine, stopped in park ... and then no longer lockups).

A dealer scan showed that the lockup command was being sent to the tranny. The lockup solenoid has been replaced - no difference.

Any insite or how to test/diagnose ? The TC and VB are both Revmax with ~ 45k miles.

thanks
 
Sounds like they have lost their return circuits (but this should yield a code)
 
Make sure your pcm is commanding lock up, test the lock up solenoid on the valve body, look for pieces in your trans pan which may be your boost valve (spacer, valve, spring and retainer clip) which is located on the top of the valve body.
 
What does starscan actually show? The PCM switches ground. Put a jumper wire across the trans relay to feed it constant source. Search for the write ups on lockup switches for a photo of which sockets to jump.

From my Not-So-Smart phone
 
First thing I would do is swap the Trans Relay. You can grab one from something else that works but you don't need, like AC.
 
That's what I was doing by saying to jumper the relay. This feeds 12v to the trans without pcm control

From my Not-So-Smart phone
 
i agree with biggy, just rig it up like you would a converter lock up switch...

if it locks up the relay is good and you have a wiring/ PCM problem. if it doesn't it a solenoid issue.
 
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