I'm already taking my car into the dealership this thursday to have the rear bearing replaced and told them I may have them drain the tranny fluid as well, even though they insist it doesn't need done without even looking at it.

I feel like it would fix the problem I've been having after reading several threads on here where it's fixed others who have had shifting issues.

Right before the car shifts out of 1st, I have to release the gas a little and let it sort of fall into 2nd very slowly, then I'm fine. The warmer the car gets, the worse the problem gets; to the point where it jerks very hard and gets stuck in 1st (sometimes 2nd) and I'll get a gear fault and have to restart the car.

Sometimes while at highway speeds, if I floor it too quickly to overtake someone, I'll get a gear fault and be stuck in I think 4th gear. At which point I have to pull over and restart the car.

I have a 2003 STR with about 116k miles on it. Before I go spend $350-$400 to have the tranny fluid replaced, what do you guys think? If the transmission needs work then I'd just be wasting the fluid I already have as it'd probably be drained anyway during service.

 

Do you know the box has the right software? Some of the early cars had issues which were cured by a new rev. though yours sounds probably mechanical. I suppose checking the fluid level would be cheap even if marginal topping up was also needed.

 

Phalaex, we have the same year and identical mileage STR's. I "had" the identical poor trans. shifting as you. jagv8 is spot on in being sure you have the revised ECU/TCM flash. Though I was happy to have this performed it made no difference. The trans. fluid was swapped a while thereafter and still the erratic shifting issue remained...Until yesterday. Upon the advice from a gearhead bloak in the UK, new Bosche O2 sensors were installed in place of the 117k mile units (RockAuto $360 for all four)...Wa la! No more surging until warm-up (O2 sensors), smooth shift patterns, smooth engine, and more power throughout the RPM ranges. In summation; O2 sensors play a major role in ECU/TCM decisions.

 

They are indeed a major input - mainly the upstreams, so if you are going to change any then do those. (Sadly, they're the more expensive type.)

 

Are the sensors easy to access? Is there a way I can test whether or not they are in fact the issue without having a scanner?

 

Yes you can manage without an OBD tool if you have a 'scope (oscilloscope) and are good with it.
(But access is poor)

Absolutely not, otherwise - just get an elm327

hmm, well,if you geuinely suspected a wiring fault you could use a meter (with engine off) but it sounds unlikely to be the thing to do here.
Also, metering end to end all the way to the PCM...... you have to be desperate but it's doable if you are.

 

If all I need is an OBD scanner, I'll just borrow one from autozone. I thought maybe I needed a more specific scanner for the TCM or something.

 

O2s are connected to the PCM - see the elec diagrams - or see any OBD docs (they all describe O2s even if in small detail).
You need a tool which reads data (aka live data), not just codes. AZ don't exist here so I don't know what theirs do but a USB elm327 is about £10-15 on ebay ($15-25).

If you get desperate, read some of the old posts on here

 

I had jaguar do the diagnostic, codes came up immediately for gear 1 and 2 internal failures and the trans fluid showed signs it was burnt. They basically said I need a new transmission as they don't service the internal components. Transmission from Jag is $7300. At this point I think it's time I move on from Jag and get rid of this stupid thing.

 

When was its fluid last changed?

 

Never. I got the kit from CTSC a few weeks ago though. They keep insisting it doesn't need changed.

 

As I recall it says life is 100K miles and as I imagine you've seen on here most say to do it at 80K if not before.

Heavy duty use and you do it at 30K miles.

 

I suppose it wouldn't hurt to try since I already have the stuff for it. I looked up on car-part for a transmission, just to see my options, and called Roadmaster Engines and Transmissions :: Leader in Converters, Hard-Parts, and Soft-Parts and talked to a guy named Stacy. He quoted me at $3600 for a remanufactured tranny 2yr warranty, that included shipping from Michigan to Ohio and it's already filled with fluid. So about half the price than the dealership. I told him what codes I had, P0781, and he looked it up for me. All it said was 1st to 2nd shift malfunction.

 

P0781? Have you had the reflash done that cures that?

TSB JTB00072