Auto gearbox won't change up

[terminallybewildered]

I have a Bongo Friendee gearbox problem and I wonder if anyone can help.

It's a Diesel Permanent 4WD 2.5L automatic autofreetop, first registered in Japan 1/1/1997 - well that's what the V5C says - imported 1/6/2008.

After no problems for years (though the Hold light has come on a few times) the gearbox now won't change up out of 2nd. This happens when the engine is hot too. If the accelerator is pressed, the engine revs and will go up to 4000rpm, and beyond if I were to let it, but the road speed stays at 20-25mph ! Easing back on the throttle sometimes causes a change up but then it drops out and goes back to the lower gear or even, apparently, neutral. If I move the selector to S it seems to behave a little bit better and the road speed picks up while still in a lower gear. (If I have to limp to a repairer, I imagine I'd have to select S to get there the same day!!)

I've checked the ATF fluid level, when hot with the engine running in P, and it reads F and looks reasonably clean. Currently the vehicle is virtually unusable. Any ideas/comments anyone ? Alacrity?

Thanks.

[Simon Jones]

Do the speedo & rev counter work correctly when the problem is occurring?

[Northern Bongolow]

when was the fuel filter last changed, and has the banjo filter in the top of the pump been removed and cleaned out.

[terminallybewildered]

Do the speedo & rev counter work correctly when the problem is occurring?

Yes they do.

[terminallybewildered]

when was the fuel filter last changed, and has the banjo filter in the top of the pump been removed and cleaned out.

I don't know the answers to these. Will have a look. Thanks.

[terminallybewildered]

when was the fuel filter last changed, and has the banjo filter in the top of the pump been removed and cleaned out.

I don't know the answers to these. Will have a look. Thanks.

Have a had a look at the air filter and that's pretty mucky in one place. Have ordered replacement plus new fuel filter on the basis that it won't do any harm to replace them both whether they need replacing or not. Will look to clean the banjo filter too. So I gather that the gear change behaviour I described CAN be due to fuel 'starvation' then . . . . ?

[Simon Jones]

I would say that trouble getting to the top of the rev range is a symptom of blocked fuel / banjo / air filter, although I've personally not come across reports of it affecting the gear change.

[Northern Bongolow]

ive done several simon, one of them twice, this bongo lives in a little village with an old fashioned filling station, got knows where he get his bad fuel from.

when the filter or filters get blocked the engine thinks is labouring or pulling hard up hill, this can fool the box into hanging on to gears or not changing up at all, they can even stall. the fuel filters can have a by pass valve in them so when the filter is dirty fuel can literally get around the element so keep running, but usually not run well.
get the best branded named filters you can afford.
there is a small filter on the end of the tank pick up pipe also, remove the supply pipe to the fuel filter and a quick couple of blows back to the tank can help clear this.
the above is good maintenance anyway and could be a cheap fix.

[Simon Jones]

Actually, that makes a lot of sense .

[Northern Bongolow]

for a change ---------

[terminallybewildered]

ive done several simon, one of them twice, this bongo lives in a little village with an old fashioned filling station, got knows where he get his bad fuel from.

when the filter or filters get blocked the engine thinks is labouring or pulling hard up hill, this can fool the box into hanging on to gears or not changing up at all, they can even stall. the fuel filters can have a by pass valve in them so when the filter is dirty fuel can literally get around the element so keep running, but usually not run well.
get the best branded named filters you can afford.
there is a small filter on the end of the tank pick up pipe also, remove the supply pipe to the fuel filter and a quick couple of blows back to the tank can help clear this.
the above is good maintenance anyway and could be a cheap fix.

Thanks for that extra information.

[pongobongo]

Many thanks for this link and advice.

I've now changed the fuel filter, cleaned banjo filters (is there another to clean too?)

Unfortunately hasn't resolved my the slippage.

I did have the issue a few months back and changed the entire box.

Anything else I could check/replace?

Ta

[Simon Jones]

Did you have exactly the same symptoms with the previous gearbox too? That would point to a problem with the vehicle such as the throttle position sensor or the gearbox ECU which is mounted in the passenger footwell.

[pongobongo]

Exactly the same issues tbh.

Feels like a worn clutch.

Very peculiar as it only does this when the engine is warm - my son and I have been searching for the steepest hills around swansea to try out this am!! Cold - fine. Warm - won't change up.

On the original box, there was a tapping/scraping noise too when this occurred. Nothing on this box ...yet!

[Simon Jones]

What sort of ATF are you using? Are you checking the level when gearbox is hot or cold? On mine, there are different markings for different temperatures, but that's a later 2WD model.