Gearing issues

[jcantle]

Please can anyone help......

We have a 2002 2.5 V6 petrol / gas Bongo. She has been in the garage since before xmas with sign of ever coming out.

The auto gearbox goes into first gear then second then goes back to first. Initially gear box oil was changed by mechanic to no avail. Our mechanic then referred us to a gearbox specialist who refurbished the whole gearbox. Same issue. ECU check on engine and gearbox with diagnostic system comes back with no faults. All wires behind glovebox have been checked. The gearbox in another bongo and it ran perfectly so we know that the gearbox is ok.

Can anyone shed any light on this as our mechanic is really struggling.

Many Thanks

Jo

[Simon Jones]

Welcome to the forum. It could perhaps be a problem with the throttle position sensor or associated wiring. Did anything happen prior to it going wrong?

[Alacrity]

So you have taken you gearbox out & tried it in another vehicle since this problem began & it worked OK?

If so then it would look like an ECU issue to me. Just because there are no faults shown doesn't mean the transmission ECU is OK as they are rarely able diagnose themselves, if it were wiring you would have fault codes - unless someone has messed with the wiring & got things (solenoids) connected incorrectly. Then the ECU would be seeing the circuit but they would be working in the wrong order.

Did this issue just start out of the blue or did start after something had been done to the vehicle?

[mikeonb4c]

Soooooo good to see Geoff offering help on here - is da man when it comes to autoboxes and, happily for us, he is no stranger to Bongos.

[jcantle]

Thanks Guys.

It was running fine gearbox wise. It did have a LPG issue before hand which as that was foxed the gearing started playing up. It could be just co-incidence. We did get the LPG all disconected to check and it still slipped.

The garage that did refurb tried our gearbox in another bongo and it worked fine.

thanks for your advice.

[Alacrity]

Could be coincidence but may not be. Don't assume it is.

If it were here we would rig up a signal monitor (a series of LED's) on the shift solenoid wiring at the transmission end to see what the ECU is commanding. If it is commanding the solenoids to switch in the correct order then you issue is in the transmission without doubt, if not then you are looking outside the transmission.