Reverse slam, rough forward shifting, erratic RPM

Tiny
ZIGMOND
  • MEMBER
  • 2000 SATURN SC1
  • 1.9L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 84,000 MILES
2000 Saturn sc1 with 84000 miles. Mechanic swapped out a 2002 transmission because of Bad Reverse slam shifting and rough forward shifts. Service engine soon light is on. Trouble codes po733 and po734 displayed. Reverse slam is still bad and forward shifts are a little better. The car doesn't seem to shift consistently. I reset the pcm fuse and car still shows service engime soon light and same trouble codes as above. Bad car brain !
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Monday, December 1st, 2014 AT 10:55 PM

2 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
First, is the transmission exactly the same as the old one? Also, is it doing the same exact thing? The computer is determining that the gear ratio is incorrect for 3 and 4th gear. It could be a mechanical issue within the trans, a fluid issue, a problem with shift solenoids.

If it is doing the same thing as before, I would question the TCM.
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Tuesday, December 2nd, 2014 AT 5:24 AM
Tiny
SATURNTECH9
  • EXPERT
Just to add to this one what were the codes and symptoms of the old one? What year and model did the donor transmission come out of?As far as the tcm being bad really doubt that I havent ever seen one go bad and cause those issues. The delay bang into reverse is common most common reason for it is the input shaft nut loosens up. Or the pressure regulator bore in the valve body wears out and causes too high or too low of line pressure in the transmission. Usually causes too low of pressure and you will gets a delay slam into reverse and sometimes you get forward gear codes usually 3rd and 4th gear. Also the wires going to the transmission on the valve body the copper breaks inside the insulation and causes gear codes etc. There is also another issue that happens the grey 68 way connector to the inside fuse box. The big red wire to it terminal f5 I believe is open causing intermediate power to the transmission actuators. Saturns are my expertise so please let us know whats going on so we can figure this out.
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Saturday, December 6th, 2014 AT 7:34 AM

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