Hi,
The cold 1-2 shifts on my 1999 AU have been getting steadily harsher. However after running for a short period they appear to improve. Then after driving in traffic (stop start) the gearbox appears to go into 'limp home mode'. As the acceleration from standstill is very slow, with no apparent gearchange. My initial thought were a faulty S5 solenoid (the harsh shift). However the other shifts although not perfect are far more gentle. I've recently purchased an Autel US703 scan tool and on a recently experiencing 'limp home' the error code P0753 was depicted. The Max Ellery manual states 'Shift Solenoid S1 electrical problem' and 'This DTC will cause default operation mode #9A'. The manual doesn't say what 9A is, I'm assuming it's limp home. If I then clear the fault whilst in motion the gearbox operates normally (limp home is removed) and the fault doesn't immediately reappear. According to the small amount of information I have about the BTR box (where can you get a decent manual from???) The cold 1-2 shift is often due to debris blocking the S1 oil gallery (improves as oil thins with temperature, see attached). I therefore want to drop the gearbox pan, remove the valve body and clean it and the solenoids and then replace. I understand there's a couple of gaskets and a valve body filter that need replacing (changed the main filter last month in a vain attempt to improve it). Trouble is I don't know if when you remove the valve body with the box in situ whether half a dozen springs, ball valves and asociated parts then fall out and your then left scrabbling around for them. Plus whether the whole lot can then be replaced after cleaning..Any ideas as the Max Ellery is about as useful as a chocolate fireguard!
Oh I've also read that the S5 solenoid in the BTR box is the same as the one used in the GM 4L60-E gearbox, just half the price. Any ideas as I can't find any Bosch information about these solenoids.

Thanks!

 

 

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