Auto box not shifting

[BigAlan]

Ok the last few days I have been driving through the snow having fun, and today when cruising home in the traffic the automatic gearbox seems to be revving to high, like,it has forgotten where the next gear is, I got home easy and switched it all off and left it for a bit, went along the road and it seems fine, ATF fluid is fine I changed it last year as best I could, I have some more and could easily drain out what comes out and put clean in, new Radiator last year as well, no fluid loss.

I seem to remember there being a switch somewhere on the auto box which knowing me has got wet and might need either cleaning or changing, anybody know which one it is? or could it be a TPS?

Apart from that this old bus is awesome and has been for the last five and a half years, oh 126k miles.

thanks
Alan

 

[Andrew Prince]

Starting with the obvious and maybe silly questions - you're sure that the ATF level is fine? You've said the oil condition is fine, which is good!
Check the rad see that you haven't got "mayo" forming, which would indicate leakage in the ATF cooler inside the rad. Water in the ATF will cause problems. With a new rad last year this shouldn't be an issue, especially with an OEM rad but worth checking.
Once the easy-to-check things are ruled out, start looking at the TPS etc

 

[BigAlan]

OK so if everything oil and ATF wise is fine, what can one do with the TPS apart from chuck WD40 at it?

Thanks
Alan

 

[goodoldboy]

Keep an eye on the temp gauge - the box will not shift into top until the temp reaches a certain level.I have had a similar experiences here on short journeys in the cold weather (-10)

 

[BigAlan]

Temp Gauge is always normal and this happened within half a mile of getting home from work.

Thanks
Alan

 

[Beau]

In the engine bay somewhere near the oil filter there is a earth for the transmition box. Make sure this is in place and tight/clean.

I once had a problem where my autobox was not earth probably and it would take forever to change gears as well as driving off from stand still.

 

[BigAlan]

Ok people update on this.

Today i used it for work, started fine and worked as it should, then after approx 10 minutes it started to rev and it pressing the overdrive buton made no difference, its like its in kickdown mode, so i stopped and turned everything off, waited approx 30 seconds and started the car again and drove off all ok, it did it again about 10 mins and again i stopped and turned everything off again, then started and cruised the last mile into work ok.

Now from my limited knowlwdge of this car even though i have owned it over 5 years this seems like an electrical problem, possibly the TPS?

On an aside, when i reversed into the parking place it was sluggish taking up the slack so to speak, romorrow i will again drain what i can out of the gearbox and put new ATF in.

thanks for the info so far.
Alan

 

[BigAlan]

back home now and I drained approx 5L of reddish ATF fluid, filled up with new, cleaned the two switches on the side of the box.

Twice on the way home it revs far to high, I stop and turn it all off then start again and away I go, well for a while and then it revs again.

just like it has forgotten the top gears and overdrive.

any ideas?

thanks
Alan

 

[Beau]

Could the torque converter be slipping or not engaging properly and therefore revving....

 

[BigAlan]

I don't know how to check this or even if there is a test.

if there is a test I would love to know..

thanks
Alan

 

[Beau]

I don't know how to check this or even if there is a test.

if there is a test I would love to know..

thanks
Alan

I have no idea, your probably best taking it to a specialist auto mechanic who can diagnose the problem for you.

Alternatively keep your eye out on ebay for an autobox. They tend to go for about £200 which is cheap!

 

[BigAlan]

Today no drive at all after warming the car up to defrost the ice, switched off and started again and just managed to crawl back up the drive.

something serious me thinks.

Alan

 

[BigAlan]

More info.

drained the ATF out again, then started car and went through the gears slowly on tickover and then refilled it to the cold mark.

started it again and I can go up the road no problem, how far I will get before it starts to over rev I will find out tomorrow when the roads are less crowded.

Alan

 

[wobbly]

It sounds like it is an atf problem - if the atf rad core has corroded it allows antifreeze into the system.

This ruins the clutch pressure plates and seals.

What state was the original atf in? Did it look at all creamy or strawberry milkshake like?

What is the state of the coolant in the rad.

Will be interested to see how it gets on with the new atf.

Pete

 

[BigAlan]

I changed the radiator at 120k miles which was 6k ago as a precaution, there is no water or coolant in the box at all, drained and pit new ATF in Friday and sainted again today and it was discoloured as you would expect, I am intending to drive to a mate,s garage tomorrow and drain the ATF again and replace.

I shall report back tomorrow.

thanks
alan

 

[wobbly]

Cool, let us know how you get on.

 

[BigAlan]

Well today I drove over the garage and it went as it should, drained out the ATF and refilled with new, went for a ride and back again, put some Forte auto box additive in and topped it up, must have had 20L of ATF flushed through and came home, all well and working better than usual.

So in summary flushing through with lots of new ATF and cleaning the switches on the gearbox out thoroughly seems to have cured the problem.

I shall report back after a week or so.

Thanks for your advice.

Alan

 

[BigAlan]

Just over 100 miles today and spot on, smoother changes now than before.

Moral of the story, change your ATF at regular intervals.

Alan