Jumps out of gear. Why???

[Ray De Man]

Hi, just wondering what this problem could be. When driving down the freeway at a steady 80kph or going over speed humps, my auto gearbox jumps out of gear then reconnects after a brief 2 seconds. I have also noticed it slips between gear changes but this does not happen everytime.

I had it checked by a gearbox guy and he said nothing is wrong, the ecu is not showing any faults.

Could it be a worn clutch? Engine has done 170+k's

[Ray De Man]

Anyone willing to help???

[Ray De Man]

Ok, alittle more info on the subject. It does it more when the engine is at normal running temp then it does when its cold.

Someone please help!!!

[Ray De Man]

64 looks and nobody knows, cheerz guys

[kane88]

how often do you service the gearbox?

[stocky]

is it manual?

[mainpath]

could be a damaged gear box?

[Calaber]

Let's disregard the transmission specialist for a second. Too many "mechanics" these days are stuffed if a computer can't diagnose a problem for them.

Have you checked the fluid level with the engine at operating temperature? The correct procedure is to warm the engine to operating temperature, then shift it through all gear positions, then place it in Park. Switch off the engine and, within ten seconds of switching off, check the oil level. You will probably need an assistant for this procedure.

Have you checked the colour and condition of the trans fluid? What colour is it - bright red, or darker, almost brown and smells burnt?

Does the transmission act normally otherwise - change up and down correctly, or are changes slurred (slow and with slight increase in revs between changes?)

Is the transmission silent or are there noises in specific gears?

Have you checked to ensure that your transmission selector is correctly adjusted?

If you can provide some answers to these questions, somebody might be able to come up with some answers for you.

[fasamr]

as you said coming out of gear meanu got error 73 - something pressure control valve

[Ray De Man]

Ok I have tried what you said and the results are...

Fluid level is fine, showing on max.

The colour is light brown, has no real smell, just smells like gearbox oil to me.

Its starting to slip or hold in gear with revs up. In other words it sometimes gets stuck in gear before it changes down so revs are up. After approx 3 secs it will find the correct gear.

There is some noise but can't tell if its from the gearbox, diff or tyres. I only hear it around 40kmh upwards.

I have no idea how to adjust the selector, I only mainly use "D", don't normally use the 123 gears.

When I did the service the guy said he changed the filter, gearbox oil and tightened something. This was done 2 months ago, don't think gearbox has ever been serviced.

For the other guys, this is a 4spd auto.

Hope this info helps.

[brocknjess]

you actually need to check the fluid level while the vehicle is in park and engine is still running, take it for a drive around the block first, come back let it idle for a few minutes then check your auto fluid level, find out what type of fluid the mechanic used in it when it was serviced as the specified oil is DEXRON III