Intermittent gearbox fault

[phil 1]

Hi all
I appear to have a intermittent gearbox fault it seams to get stuck in 3rd gear when cold. I have owned this bongo for 4 years now and this problem has appeared to have started in the spring. I am aware that in the winter the gearbox is reluctant to change gear until it has reached a set temp i.e. stays in 3rd then changes in to 4th them lock up. Now the problem I have now is if I drive from cold strait from my house approximately 1 mile on to a fast A road (60 mph) it stays in 3rd gear for 5/6 miles then it changes into 4th then strait into lock up then it changes normally. If I go around the block and the gearbox changes up and down the gears a few times then go on a fast A road it changes up normally. Over the weekend it was stuck in 3rd for longer than it has before then it changed up normally in to lock up so I pulled out to overtake all was good as I just pulled pass the other car the gear box drops down into 3rd again at 65mph and rev counter well in the red not a pleasant thing to happen whilst over taking had to slow down again then it was fine for the rest of the trip. I have been a member of the club + forum for the past 4 years and regularly visit the forum but rarely post as I cant type so I am aware of the usual problems and I have changed the oil and cleaned the filter and I don’t have the flashing HOLD light. As I said this is an intermittent problem and a lot of the time it changes gear from cold normally for this time of year so I don’t know whether it is a temperature related the TPS or the gear box that is at fault. Sorry for the long post a please any help I will be most grateful.

[Steve L]

It is normal for the auto box not to change into top when the oil is cold, I've had other auto's that did this, I believe its to prevent damage to the box until it warms up.
Another recent poster had a similar problem as yourself (changing down unexpectedly) as did I. Mine was cured by a change of fuel filter and cleaning the banjo filter in the fuel pump. I think that when the filters are blocked you have to press the accellerator pedal further to get the same amount of fuel to the pump, this fools the gearbox into thinking you are in kickdown mode so changes down. It could well be a duff TPS, but if it was me I would eliminate it being the fuel filters first.

[eckerB]

Hello Phil,I see that you are in N-Devon.I suggest that you look at Allans-Autos website,he is near Plymstock,S-Devon.His garage is registered on this site.I had a problem with the gearbox on my Bongo-Camper whilst on holiday in Paignton.Allan was very helpful and he knows the gearbox`s well.He sorted mine out straight away.Not same prob as yours but similar.Worth a phonecall! Eric.

[phil 1]

Hi
Thanks for your replies,
I am afraid this is not normal gearbox behaviour in the winter it would hold on to 3rd for a bit then stay in 4th for bit then lock up in the wormer months it would hold on to 4th for a bit then lock up. At the moment it holds on to 3rd until the temp gauge nearly at normal temp then jumps strait into 4th and immediately locks up at the weekend the mason alarm started to chirp before changing up. I am thinking it is related to the gearbox temperature some how but cant figure out how the gearbox now’s what temperature to change up at.

[dandywarhol]

The gearbox temperature sensor in the middle of the head under the driver's seat and the coolant temp gauge sensor at the front of the head (controlling the Mason alarm) are both linked to the ECU. Might be worth interrogating the ECU for a fault code as some faults don't show up as a flashing hold light.

A gearbox oil/filter clean is recommended by Mazda at 24,000 miles AND Allan's would be your best bet down in that neck of the woods

[phil 1]

Hi
I have managed to get a fault code from the diagnostics plug it is reporting fault codes for the TPS + EGR valve. Now I have blanked the EGR some time ago but have no idea what the egr valve is or ware it is. I can only find one suppler for a TPS for a bongo and they haven’t got any in stock and will not be getting any more in at the moment due to the exchange rate. If any one tell me where I might be abele to purchase one I would be most grateful. All so in the compatible parts list it says a TPS for isuzu trooper will work with modified wiring loom. Has any one tried this and got it to work?
Many thanks
Phil