Re: A/T and A/C issues

> Can someone help me diagnose this: > > I have a 1997 Plymouth Voyager 3.3L V6 with the 4-speed A/T. It has done > 94K miles. > > When cold, it shifs smoothly, no problems at all. > > When hot, the shift from first to second is very harsh (usually, but not > always). Other shifts seem to be OK. I have also noticed a very occasional > slight bump when coming to a stop (usually only towards the end of a long > journey). > > I have changed the fluid and filter and it does not seem to have improved > it significantly. I had done 2 prior changes putting in Redline Oil's C+ > fluid. This time, I used a regular ATF+3 fluid. > > A month or so ago, I disconnected the battery to see if the tranny would > re-train itself to a better state, but this did not seem to help. > > So, any ideas? > > Also, I have noticed a significant shudder as the A/C clutch engages -- > any idees what might cause this?

You might check to see if there is later firmware for the TCM and have your dealer re-flash it (for $50-120 depending on the dealer. I don't think you will ever get it 100% bump free, but you can improve it.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

Reply to
Bill Putney
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Transmission: Three things are major cause of "bump-shift" and erratic shift.

  1. Connector on Powertrain Control Module contaminated (front engine compartment passenger side, near bottom)
  2. Failing Input and Output speed sensors (~ ea) on the trans (Hall effect sensors are affected by heat. Take off driver's side front wheel for access thru wheel well).
  3. Constants stored in the Transmission Controller Module (requires dealer "flash" with new constants or fixing the bad connections and running for 20 Key On's).

Do NOT let the dealer service sell you a trans rebuild before doing all the above!

A/C: I just had the A/C recharged after decreased cold air was unable to keep interior cool on hot days. Tech said it was low and R134 is typically sensitive to low charge. After the additional charge I noticed a higher torque requirement (shudder) for the compressor. It may be that your system has too much R134.

- Bill

Reply to
Bill Hodgson

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