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The mkiv Supra Owners Club

Autobox will not change into top gear


loks

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Not on the Supra but on the Aristo, so hopefully someone from the family can help me here ;)

 

I was driving this morning and noticed a slight hesitancy when the autobox was up changing. However once I entered the highway the gearbox refused to change into 3rd (top) and I was stuck in 2nd until the next exit.

 

I tried changing by manual and flicking the O/D on/off but without any luck.

 

I checked the fluid level about 2 weeks ago and it was OK then.

 

Anyone able to help me out with some advise or has anyone else had the same problem?

 

Thanks for any help.

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Didn't notice that happening at all at the time but the idling revs were higher than normal just before I turned the engine off. Will check this tonight on my drive home.

 

Now that you mention it, I have notice that the rev counter has stopped working (for a few seconds at a time) on 3 occassions over the last month or so - that I have noticed anyway. Related?

 

I just blamed that on the gremlins.

 

 

I have now arranged to have the gearbox oil changed just in case.

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Cheers for your prompt replies Jagman :thumbs:

 

Will have the mechanic check this out too.

 

In HK using Km/h, so no need for the speed convertor.

 

 

.... minds in overdrive again, would a dodgy battery have any impact on my problem? As the lecky wing mirrors and drivers window were a little sluggish in action this morning also?

 

Probably clutching at straws now :blink:

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Check battery connections are clean and tight. Do you check the auto box fluid using the correct method?

 

Will check battery terminals tonight - never thought of that as a potential issue.

 

Check the autobox by moving to level ground... cold - before starting engine and level between the lower marks. Start engine to warm, move through the gears R N D, R 2, R 1 and check level between upper marks. Am I doing something wrong?

 

For info the level was slightly above the upper level mark range and was a mucky brown colour - not black.

 

 

As for the box performance today, it is doing my head in :(

 

 

When in "D" & in Normal or Power mode the car will not not come out of 1st gear.

 

When in "2" & in Normal mode the car will not come out of 1st gear but when I switch to the Power mode it will change up to 2nd gear and stay there, even when stopped and pulling away.

 

 

 

Will running an engine diagnosis test find the problem with the box?

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the gear box oil should be red,not brown maybe the oil is burnt from it being hot or old,the gear oil lvl should be tested after it has run for a fair few miles then park on lvl ground,run the gear lever through all gears then put it in park and then test the lvl,s'nd hand gear boxes are cheap,might just be easyer to get another box with diferent oil cooler?

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  • 1 year later...

Sorry to resurrect this old thread but the old problem, went away, came back with avengence and now, although the car is with a new owner, it has thrown up another question for you kind techies.

 

Long story short, I had a problem with the autobox with it being reluctant to change up through the gears. Did all the stuff recommended, checked fluid and even changed it but mechanic told me it needed a new box. Decided to sell the car for spares but the buyer was a real enthusiast and decided to change the box for a new secondhand one, it did not fix the problem. So he decided to try another autobox just in case but still the problem remains.

 

What else could possibly stop your gearbox from changing up through the gears apart from the gearbox itself?

 

Anyone know how to check the gearbox ECU?

 

Thanks for any help all.

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There is no separate gearbox ECU. The gearchange is controlled by the ECU switching two solenoids on or off, giving four combinations, one for each gear. The solenoids are in the gearbox, so I suppose it's unlikely that three 'boxes had the same problem. Could be the wiring or the connectors, perhaps?

 

Is it 3rd or 4th that's not working? Is there a problem with the O/D button that means O/D (4th gear) is permanently off? Also, the ECU will not engage O/D until the engine has warmed up, so could there be a temperature sensor issue?

 

 

http://www.mkivsupra.net/vbb/content.php?51-Repair-Manuals

http://www.autoshop101.com/

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  • 1 month later...

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