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2000 Jeep TJ Wrangler 32rh Erratic Cold Start Performance

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Hi my Jeep started acting up when its cold (after sitting), you engage drive and it will drive normally and then suddenly rev like its in neutral and then just as suddenly engage and drive normally. After it is warm the problem goes away. Even if you shut it down, as long as its warm the problem goes away. Any thoughts? I was going to change the fluid and filter check the bands, but not sure what else I should look for before I refill it

Thanks

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Welcome to the forums, B.M.A.C.  Your 32RH is experiencing a classic case of a Chrysler RWD transmission with an empty torque converter!  I discuss this, and a solution, at the magazine: http://www.4wdmechanix.com/Survival-Upgrades-for-Jeep-and-Dodge-Ram-Automatic-Transmissions?r=1

The actual issue is torque converter drain-back.  The RWD Chrysler transmissions (904/999, 727, A518, A618, RH and RE types) do not pump fluid into the converter in Park mode.  You start the engine, and if the anti-drain-back valve to the torque converter has not been holding, the converter does not fill while you're idling in Park.  A drained or semi-drained converter does not lube the front pump bushing.

Your only clue is the lack of gear engagement, the "Neutral" sensation.  You're experiencing the partial converter fill with the intermittent free-wheeling.  

Our Ram's 48RE first exhibited this issue after the truck had parked for weeks.  I ran the engine in Park for a minute or so to circulate engine oil.  When I shifted to Drive, there was no movement for several seconds, then the vehicle began to move.  I've worked with automatic transmissions professionally since the late 'sixties and immediately sought a remedy...You'll find my discussion and fix at the link.

To cure this without the use of a Sonnax full-pressure lubing valve, you will need to restore the anti-drain-back function.  A new anti-drain-back valve would be the fix.  (Flushing seldom works.)  A repaired or replaced anti-drain-back valve will hold fluid in the converter when the vehicle is parked or started and run in Park.  A filled converter will work normally during gear engagement.

Considering the lengthy history of this Chrysler design quirk (try 1962-up!) and its serious damage potential (front pump bushing failure and more), one must marvel.  Sonnax engineered a ready solution to this problem, primarily for the transmission rebuilding industry, likely to protect warranties on transmission work.

Moses

 

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