Jeep TJ hesitating and then lurching forward when first put into gear

tdseventh

tdseventh

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Original poster
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Nov 26, 2020
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7
Location
Grand Rapids, MI
Hey Jeepers,
I've got a 2001 TJ 4.0 with 176K miles on it. I've noticed that it's first put into gear that it hesitates to move forward, then "lurches" and dies. This only happens when it's cold, and when it's warm, there are no issues. I've changed the Idle Control Valve (I think I have it configured correctly) and both O2 sensors were replaced not long ago. Should I consider draining & replacing the tranny fluid? Or is there another culprit that could be the issue? Thanks!

Troy
 
Try idling it in neutral (not park) for like 30 seconds before you put it into gear & report back.
 
hear said:
Try idling it in neutral (not park) for like 30 seconds before you put it into gear & report back.
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Will do. I have heard that the transmission coolant line may need replacing because of a leaky check valve. I've got the TJ skid plate off right now but I'll check it once it's back up.
 
Yeah, the check valve allows the torque converter to drain back, which causes a problem going into gear until it recharges. And the 32RH does not recharge the TC while in park, only in Neutral.

Sonnax makes a replacement manual valve which can mostly mitigate this but I have yet to actually try it.
 
hear said:
Yeah, the check valve allows the torque converter to drain back, which causes a problem going into gear until it recharges. And the 32RH does not recharge the TC while in park, only in Neutral.

Sonnax makes a replacement manual valve which can mostly mitigate this but I have yet to actually try it.
Click to expand...

Thanks for the info. Any chance you have a link to that valve?
 
hear said:
Try idling it in neutral (not park) for like 30 seconds before you put it into gear & report back.
Click to expand...

Its idling fine in neutral and park, I can quickly save it from dying if I shift to neutral before stopping but as soon as I shift to drive it dies.
 
trailing101 said:
I did it park but not in neutral, does that make a difference
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Yep, definitely makes a difference. The dipstick even says check while warm & in neutral.

As long as we’re at it, if you need to add, use ATF+4 only. Slightly over full is better than slightly under.

Although usually low fluid will just make it not want to shift at all or just slow to shift. Flat out dying feels like a torque converter problem.
 
Okay, one more possibility: I recently replaced the IAC valve, could I have set the valve improperly? I've also cleaned out the throttle body, but it hasn't remedied the problem so far...
 
tdseventh said:
Okay, one more possibility: I recently replaced the IAC valve, could I have set the valve improperly? I've also cleaned out the throttle body, but it hasn't remedied the problem so far...
Click to expand...

provided it's working properly, the IAC is self adjusting.
 
Okay, reporting back. There's still some testing to do, but I found a video on YouTube talking about similar symptoms. He cleaned the Throttle Body with some TB cleaner, a toothbrush, and some shop towels. And lo and behold, I haven't had NEAR the problem with lurching when put into drive. I'd give that a try.
 
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