I have suddenly lost reverse gear on my 2000 Saturn SL-2 with 108,000 miles of mostly (95%) highway miles. I have done the automatic transmission fluid and filter changes every 30,000 miles. There are no tranny fluid leaks, or fluid loss. The A/T has worked flawlessly up until four days ago.
On the first day, the A/T started to hesitate to shift into reverse (from park). The engine would rev up to 1500rpm for two seconds, settle back down to normal idle speed, then the A/T would shift hard into reverse. This pattern repeated whenever I shifted into reverse during the first day, whether the engine was cold or hot.
On the second day, the reverse gear problem continued and a new twist developed. Sometimes the first-to-second gear shift would be a hard jerk instead of a smooth transition; usually when accelerating moderately from a stop. The A/T would usually jerk-shift into reverse when the engine was cold, but now refused to engage in reverse at all when the engine was hot. The first-to-second jerk still occurs intermittently.
During the last two days, the A/T refuses to shift into reverse whether the engine is cold or hot. The first-to-second jerk still occurs intermittently.
On the last day, the SES lamp came on. Had the codes retrieved and got a P0113 and P0732. P0113 is Intake Air Temperature sensor input above maximum acceptable range. I plan to replace the sensor ($8.00) and get the SES lamp reset. P0732 is Gear 2 Incorrect Ratio. This code was stored in memory two times, along with the P0113.
I am not sure what to make of the P0732 code. Does it indicate that an external solenoid/modulator part needs replacement to fix my reverse gear problem? Or, does it indicate there is an internal (i.e. expensive) problem in the A/T that requires the attention of an A/T mechanic? If anyone else has had this problem, and had it diagnosed by a mechanic or had it repaired, I would apprecate your input. Thanks for any help.