Does the pin of the interlock solenoid definitely get pulled into the solenoid when you put your foot on the brake? Is that what you mean when you say the brake switch is working fine? Phil

The most common symptom of a worn rear stator bush is an issue with the 3-4 upshift and the TCM detecting E-clutch slip in 4th gear and shifting the transmission back down into 3rd. The E-clutch is used in 4th, 5th & 6th gears so the transmission refuses to upshift beyond 3rd gear, when under...

Most likely the rear stator bush is worn, allowing the E-clutch circuit to leak. Phil

Actually, having given this some more thought, I’m talking rubbish. You can see that the lip seal is installed into the shift motor the ‘wrong way round’ i.e. the front of the seal first, because it’s there to prevent the transfer box fluid tracking into the shift motor, not to prevent the fluid...

I think that many users never select low range during their entire period of ownership, so the lip seal, which is designed as a rotating seal, ends up as a static seal. (The same reasoning also applies to the rotary potentiometer in the shift motor which is notorious for going faulty...

The O-ring seal is a bit ‘belt and braces’ because the lead screw has a lip seal which should prevent any fluid escaping. So, you may need to have a look at this seal too. New Venture Gear was an American company, so I don’t know if the O-ring would be metric or imperial. The spigot...

A crunching sound when moving the lever into Park is usually a sign of something disconnected downstream of the transmission output. It’s caused by the parking pawl ratcheting on the park lock gear, even though the park lock gear should be stationary. This could be caused by an issue with ...

…and does the gear position displayed on the instrument panel correspond exactly with the position of the gear lever i.e. D in D, N in N, R in R & P in P? Phil

I admire your optimism. So, to recap, the car made the ‘big bang’ when accelerating in a forward gear. It will still engage and drive forwards but, since it made the noise, it will no longer engage or drive in reverse. Is that correct? Phil

There have been so many posts about DTCs related to the inhibitor/gear position switch on the 6HP26 transmissions recently, that I thought I would try a quick and dirty test to see if I could measure the switch in operation just using tools many people already have lying around the workshop – in...

Hi Justin, Yes, P0705 indicates a problem with the inhibitor switch. This switch is also known by many other names, including: xyz switch gear position switch neutral safety switch selector switch The switch is hidden behind a tin cover behind the selector lever on the RH side of the...

This doesn’t sound right. Are you sure that something else (e.g. the inhibitor switch) isn’t putting the transmission into failsafe when the gear lever is moved? Once in failsafe the mains pressure is not modulated which causes the gear engagement from Park or Neutral to go in with a bang. As...

Yes, I would give it a go. It’s easy enough to drill out the rivet heads and disassemble the inhibitor switch to clean it up, you just need an effective method (small screws?) for clamping the assembly back together again afterwards, which will keep it water-tight. You can test its function with...

The GM 5L40-E transmission has five solenoids : Pressure control solenoid TCC PWM solenoid 1-2 shift solenoid “A” 2-3 shift solenoid “B” 4-5 shift solenoid “C” so the difficulty is knowing which of these your generic code reader identifies as solenoid 1 My guess would be that it’s probably...

Sounds like the Direct Clutch is on its way out :( Phil