Autobox gear changes

[catzi]

Hi Folks,

Can someone tell me roughly, when the gear changes should happen on the 2.5D auto box? Mine seems to change a couple of times up to about 15 miles an hour and then not change again until about 40 (about 45 if your pushing it up a hill) also, the lockup seems to waver around 60mph - if you're trying to maintain a constant speed around 60 it seems to drop in and out of lockup.

The Bongo's been like this since I've had it but I wonder if there's anything I can do - TPS adjustment? It sort of feels like there should be another gear.

Thoughts on a postcard please.

[rita]

This might give you an Idea.


Gear Ratios
(mph/2000rpm) for each
gear.
1st – 11.2MPH
2nd – 20.4MPH
3rd – 32.0MPH
4th – 50.3MPH

+/- 8%

[scanner]

If you aren't booting it hard you should be 4th, locked up (and staying locked up) by about 40mph.

[francophile1947]

Don't know about the lower gears, but the lock-up should engage at about 40mph if using a gentle throttle.

[Driver+Passengers]

It sort of feels like there should be another gear.

Yeah, they all do - shame that...

Sounds like you should try tweaking your TPS and see what happens.

[Muzorewa]

Can you grab a drive in another to see how it compares? Agree that at 40mph it should lock up, as low as 38 on really gentle throttle or up to 45-50 if you're booting it, but everyone's driving style is different.

[Hollis]

Hi

Is that the same for the V6 also what do you mean by "lock up"?

Derek

[catzi]

Hmmm. I'm not sure I'm seeing a gear change around 30mph. I seem to go from 20 up to 40ish.

As Muzorewa suggests, I could really do with driving another one for comparison.

I also wonder if the TPS is adjusted correctly but don't want to really start random fiddling (I don't want to break it). I know there are quite a few posts about adjusting TPS but I'd quite like to know if there is a de-facto method for testing that it's working correctly - quite happy to poke around with the multi-meter.

[M 80NGO]

The TPS has an electrical setting engine off ignition on then slowly depress the accelerator pedal until it's full depressed at which point it should be at a certain electrical resistance but i can't for the life of me remember what the reading is

[Northern Bongolow]

and its all controlled by the temp of the coolant, or to be more accurate the fan switch, and the temp probe in the gearbox.
so if you jump in and set off it wont change correctly until its warmed up.
nice new gearbox oil, and a cleaned out/replaced gearbox filter, good front rad with a cleaned out gearbox oil cooler also will make a difference.

[catzi]

The gearbox oil has been changed (when I first got it and the filter was removed and cleaned). I'd just like to know if the TPS is operating correctly as something else to rule out.

[Driver+Passengers]

The gearbox oil has been changed (when I first got it and the filter was removed and cleaned). I'd just like to know if the TPS is operating correctly as something else to rule out.

Someone should know the voltage or voltage range for the TPS - I don't. But it's quite possible that your TPS is operating correctly but is set/rotated incorrectly.

If your 'late' gear changes are down to a functioning TPS that is set incorrectly, then my understanding would be as follows:
- ECU won't change down easily because it thinks your pedal is further down than it actually is.
- work out which way the throttle tickles the TPS, undo the two (?) screws and rotate the TPS in the same direction (it can be a bit of a head-muddle working this one out as it's upside down... )

It could be something else, but this should be an easy thing to try. Probably easier than probing it and measuring voltages. Another member recounted to me his tale of fiddling. He said that after rotating it and going for a drive, in top gear he couldn't get kick-down to occur in order to overtake - he'd rotated it too far. After it was backed off a little, everything was fine and dandy.

If it was my van, I'd give it a try, but you're absolutely right to be cautious and seek advice. Worth driving another and hopefully the owner of that van can give you a hand...

[teenmal]

Closed ~ 1.3v
Open ~ 4.2v

Make sure that you dont have any flat spots when taking the readings.(faulty track)

[catzi]

I think I'm going to have a look at the TPS today, check the voltages, and do some very gentle fiddling!

[jaylee]

Mine seems to change a couple of times up to about 15 miles an hour and then not change again until about 40 (about 45 if your pushing it up a hill) also, the lockup seems to waver around 60mph - if you're trying to maintain a constant speed around 60 it seems to drop in and out of lockup.

This might give you an Idea.


Gear Ratios
(mph/2000rpm) for each
gear.
1st – 11.2MPH
2nd – 20.4MPH
3rd – 32.0MPH
4th – 50.3MPH

+/- 8%

Just a thought...! Could yer speedo be over reading the actual vehicle speed...?