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

Just to mention that you should disconnect the battery before removing the 40-pin ECU connector for the continuity tests and, once the battery is disconnected, you may need to lift the latch gate manually to allow the shift lever to be moved through each gear position, for the checks. Phil

Your problem is either a selector cable adjustment issue or an inhibitor switch (xyz switch) issue. Clearly, it’s easiest to check the cable adjustment first. Underneath the vehicle, I would suggest that you slacken off the clamp bolt, slide out the cable, check that the clamp bolt is free to...

You have the ZF 5HP24 transmission and the New Venture Gear NV225 transfer box. The critical thing is whether or not ‘P’ is lit up on the dash when the starter fails to operate? Can you also just confirm that the message centre displays TRANS. FAILSAFE PROG rather than TRANSFER FAILSAFE? Phil