Auto box not changing up to 3rd

[mercurykev]

A friendly RAC man just drove my wife, my bongo and I from Blairgowrie to Edinburgh. We had been 10 miles north of Blairgowrie, heading towards Braemar and the auto box started playing up. 1st to 2nd was fine and then initially it was 4,500 - 5,000 rpm before 3rd would engage and after 5 mins 3rd wouldn't engage at all. We turned round and limped back to Blairgowrie and called the cavalry.

As a bit of background, a fortnight ago the bongo sprung a leak on the ATF coolant pipe and on Tuesday I had brand new pipes fitted. The coolant leak resulted in very similar gear change problem but tonight the RAC guy couldn't find any leak, plus the ATF level was checked, while running the engine and going through gears, it was at the max level.

Assuming there isn't a leak, anyone have any idea of what the auto box issue might be? Anyone experience similar probelm and found a solution?

Help is appreciated.

[Northern Bongolow]

which engine do you have, if its a diesel was it the over the starter motor coolant pipe (the s shaped one that was replaced).
this is very near the engine temp sensor, its just above it, this controls the glow plug trigger temps, and the front fans, and tells the ecu that every thing is warmed up so allowing the gearbox to select top cog. maybe the wires to or the sender is acting up, grab the sensor gently and see if the end wobbles, this will allow the resistance to vary sending duff info to the ecu.

another fault could easily be just the fuel filter or banjo filter, the engine is struggling to accelerate due to lack of fuel, so it tends to kick down a gear or hold in a lower gear.

[mercurykev]

The engine is a 2.5 diesel.

The pipe that was replaced was the twin gearbox oil coolant pipe, is this the one you were describing?

[mikeWalsall]

The pipes you have pictured are the fluid cooler pipes ..

They pump transmission fluid to ... and out of a tank at the bottom of the radiator..

As they where corroded .. a common problem.. then you will have lost some Dexron transmission fluid ..

You say the fluid was checked .. but has the fluid been re - checked (with the engine running) and topped up to the proper level .. because after the initial top up .. quantities of fluid have to fill the valve blocks / toque converter which would lower the dipstick level ..??

[mercurykev]

The pipes you have pictured are the fluid cooler pipes ..
You say the fluid was checked .. but has the fluid been re - checked (with the engine running) and topped up to the proper level .. because after the initial top up .. quantities of fluid have to fill the valve blocks / toque converter which would lower the dipstick level ..??

The pipes were replaced by the garage on Tuesday and they topped up the system then. I must admit the first thing I though was ATF fluid leak and when the RAC guy came he checked the level with the engine running and after he'd been working through the gears. The level was actually just above the max marking.

[mikeWalsall]

Maybe a Autobox specalist job ..??

There is a filter and magnet inside the gearbox .. so maybe unlikely .. but I wonder if any rust / debris as got into the box from contaminated fluid .. and found it's way into the valve block ..??