Bongo Fury

Recently (possibly related to cooler weather?) Jaws (diesel 2.5 auto) has had a problem in the morning. Engine starts first turn as usual but engaging Drive on the auto box leads to unpredictable results. This happens when the temperature overnight has been below about 15 C.

Moving forward initially is fine but then slowing or stopping e.g. at end of road, is a problem. At this point Jaws attempts to surge forward in the 'wrong' gear and stalls when I hit the brake. My impression is that the auto gear box is not responding as it should. Restarting is easy enough in Park, but moving to Drive causes another stall.

These problems stop once the engine/gearbox warm up a little and then everything is back to normal. Do I need an auto gearbox expert or an auto electrician?

I have checked the ATF level and this is actually above the Max mark although I have never topped it up. My impression is that there may be some valve sticking in the auto box but I have no expertise in this area.

Any suggestions welcome.

i would check the fan switch on the rear drivers side of the head, check the connections, and replace the switch itself if the end plastic bit is at all wobbly, it breaks off the main brass bit.
this bad connection is possibly sending mixed messages to the ecu that the engine is up to temp, then not, then is, etc.
this would activate the cold start solenoids then not etc, this also controls the glow plug temp message so they also are confused, hense the problem rearing its head in the now colder weather-----------------------maybe .

if you replace this switch the coolant system will need to be bled.

also check the fuel filter and the banjo filter in the pump top.

is your cold start working with engine initially reving quite high

then returning to normal after a few minutes

Thanks guys and sorry not to get back quicker.

Wiring all looks OK but who can tell? Starting from cold Jaws just goes to about 800rmp as 'tick over' and if left to run occasionally drops to about 700rmp as fans etc kick in.

Problem currently occurs when setting off cold (10c) and then trying to slow and stop. It's like stopping a manual gearbox car by braking and not using the the clutch or being able to take it out of gear.

Experiments find that it the situation is possibly better if using left foot braking and keeping the revs up with right foot when stopping.

All this disappears once engine warms up a little. Perplexed.

Probably not the root cause of your problems, but sounds like fast idle is not working.

Mine starts at around 800 and will creep up to 1500. At one point it was see-sawing up and down - I'm wondering if there's a problem with mine, too. Anyway, there rubber vacuum hoses can perish quite easily. I posted some stuff on the tubes here, in amongst other stuff.

Under the driver's seat towards the top of the engine, check all the rubber hoses to and from the solenoids. Check under the inlet manifold - there's a metal vacuum pipe on a bracket hanging off the second from right inlet manifold bolt.

Good luck with the rest of it.
M

you could try turning a/c on as the other solenoids supposed to then up tick over a bit

It's like stopping a manual gearbox car by braking and not using the the clutch or being able to take it out of gear.

If that is indeed what is happening then that would indicate the lockup clutch is on as that will give exactly those symptoms, though quite why it would be on is difficult to guess as it shouldn't be working at all when cold. Poss valvebody, solenoid, pump or converter issue if that is definitely what is happening. If you knock it into neutral as you stop does it avoid the stall?

Thanks Alacrity. As you suggest it does seem as if the lock up clutch is operating when it should not. As I said, this seems to be less likely if maintaining revs while braking to a stop and yes, if I can knock into neutral, no stall.

On the other hand, restarting after a stall is OK but as soon as any gear is selected then she stalls immediately. Again moving from neutral to drive if a stall has been averted has the same effect. I repeat, all this disappears once the engine temp rises above around 20c. I refer to one of Hayden's excellent cylinder head temperature monitors for this.

I leave the aircon on 24/365 but have tried switching off with no different results.

Being a muddle head amateur I have no idea how the lock up clutch is triggered normally, let alone why it would kick in when cold at slow speeds Is it autobox specialist time?

Like a diesel engine...too much oil is as bad (or even worse) as not enough.

I'd be tempted to extract some ATF to bring the level to MAX at the very least, ideally i'd change the fluid and clean/replace the filter.

Fair suggestion. Another use for the trusty Pela pump

No problems before now though which is why I am foxed.

Hmm... maybe the fluid is past it's best, plus overfilled, plus the cold? Possibly... I'm no expert by any means.

The overfilled gearbox wouldn't account for the stalling issue though... even if the box was selecting too high a gear, the torque converter would take up the slack and stop a "stall".

Try taking the level of the gearbox with the box "warm" Engine running, and in "D" for a true level on the dipstick.... Get a helper to hold the bongo footbrake firmly on whilst you do this, and/or chock the wheels so you don't have a runaway bongo!

The pela is ideal for extracting ***Ml's of fluid from the box if need be.

Thanks for that. I did consider whether the level should be checked hot or cold. In previous vehicles I have owned it was always the warm level but in this case Jaws seems to register high in either state. Not considered the idea of putting her in Drive with the driver seat cocked up before This would need a serious set up to maintain braking pressure.

As to fluid state, I assumed that it would have been changed during the "57 point check" the vehicle received on import two years ago. The stuff on the dipstick looks pale red and doesn't smell bad. Still, seems worth extracting some and making sure the level is correct. Or just extracting it all and replacing I suppose.

Is there a recommended product for replacement?

If your Bongo is from where I suspect then I can tell you that the fluid is not changed under that check so could well be worth changing it anyway.

millermatic atf DM not un or um. far exeeds dexron 111.
not cheap but the best.

not sure if i would waste it though if it turns out to be a box fault if im honest.------ sorry.