Hi a ll.
I'm looking for some help with an issue in my P38.

When i got it, i knew it would not go into low ratio but after researching common faults on here, I purchased it anyway.
After a few days I got underway investigating and was pleased to find the transfer box motor had solid grease inside, so gave it a good clean and regreased....all is well or so i thought.
It shifted from high to low and back again for a day or so but then the next day I got in and it constantly displays SELECT NEUTRAL on the message centre. I can no longer change from high to low ratio, the selector does with no trouble at all but no change is heard nor does low ratio engage.
I've checked the motor still operates and it does.
I now have only the automatic 4 gears at daft high rev changes and instead if sitting at 70 with about 2k revs it sits at at over 4k revs.
Since this SELECT NEUTRAL message has been displayed I have noticed the following;
Loss of overdrive
Longer range between gears
Can no longer hear indicator relay
Increased fuel use (of course due to gear issue)
Unable to use sport/manual button
Flashing gear selector position board

I have done the following.
Replaced coolant temp sensor as was reading at -39 on live data...now spot on
Checked TPS and it seems fine, increase in percentage on live date when pressed and vice versa
Cleaned MAF abc confirmed live data info
Checked AIT on live data and numbers add up there

Vehicle is 4.0ltr V8 with Auto box 1998 model

Any advice or suggestions would be greatly appreciated.

Do a gearbox fluid and filter change then report back....won't help the select neutral message but will hopefully help the gear changes and flaring.

Select neutral message is either transfer box ECU burnt out due to sticky transfer motor, or the switch pack on the transfer motor gone south (bith common faults)

Sorry I forgot to mention that I have done fluid, oils and filters throughout on the day I got it as never trust other people's claims of "it was done a couple of weeks back"
It drive fine afterwards.
I believe after yet more research that the gear issue is in fact limp mode.

However I will investigate the transfer box ecu and if its not showing signs of burns or smell bad I'll change out the box motor

Many thanks

Well thats the first bit done, the auto box ecu is clean, un burnt and no bits in it
Hoping its the motor switch that way I can get rid of the bloody neutral message

Not the Gearbox ECU, the Transfer Box ECU....same place mind, just one sits above the other!

Check the transfer motor switch pack...Logic Diagram is in RAVE for confirmation of correct switch signals.

As for the Gearbox issue....some have reported good things with Lucas Transmission Fix....sometimes the Valves in the Valve block get sticky, this stuff unsticks them and makes them glide better, reducing flaring and clutch pack wear....takes about 500miles or some for it to take good effect.

Saint.V8 said:

Not the Gearbox ECU, the Transfer Box ECU....same place mind, just one sits above the other!

Check the transfer motor switch pack...Logic Diagram is in RAVE for confirmation of correct switch signals.

As for the Gearbox issue....some have reported good things with Lucas Transmission Fix....sometimes the Valves in the Valve block get sticky, this stuff unsticks them and makes them glide better, reducing flaring and clutch pack wear....takes about 500miles or some for it to take good effect.

Click to expand...

Others discovered that doing the first ever fluid and filter change at 110,000 miles resulted in fitting a new gearbox at 115,000 miles.
Ouch!

dogsbody said:

Others discovered that doing the first ever fluid and filter change at 110,000 miles resulted in fitting a new gearbox at 115,000 miles.
Ouch!

Click to expand...

Too true, known (unofficially) as New Fluid Syndrome.....basically ATF is a very good detergent and all the harmless crud stuck in harmless corners gets displaced into the new fluid...making it ten times more debris filled than it was originally, causing premmature wear and component failure.

I read on here if u do use transmission fix stuff do another fluid filter change after bout 1000 miles

Considering the cost of the alternative I'd suggest at least three fluid changes.
I should have realised that I was heading for trouble when I found a date written on the filter in marker pen. It was about six months after the car was first registered.

His gear change problems have little to do with fluid. He buggered something up playing with transfer motor and whatever else he played with.

Had exactly the same and it was due to a duff transfer motor.

Replaced the motor, checked it operated when moving the selector before installing it back in the box. Problem solved.