warning light loss off power

Hi I've got a frontera 2.2 dti auto I've got a warning light which is a red cog with a ! In it I was told it's transmission related so I've changed the transmission fluid and filtet.it's goes through 1st 2nd and 3rd then won't go in to 4th ect and it just revs up to 4000 in 3rd then dies off and that cog warning light comes on and it seems to stay in 3rd I spose limp mode any ideas what it could be and what the warning light means I don't have a manual and can't find anything on line ??

Have you bleed the system as per guide and checked atf level is correct?

I drained it put it all back then pumped some fluid in it then let it idle for 3 minutes with level plug undone then filled more till it flowed out and stoped and put screw back does that sound ok ?

Thanks for your reply stretch it is what you said does anyone no if the gearbox is at fault is the gears or is the a ecu on the gear box I haven't a clue I just hope to get to the bottom of it I put a post on here a c week or so ago about the fuel injection pump failure which is what the computer came up with but there was no fault codes now this has happened with the gearbox it only started happening after my exhaust cracked at the manifold with I've had welded up

I had the car read by a snap on computer and another one can't remember the name but it's one that connects to a laptop the snap on said critical fuel injection failure and the laptop one didn't show any fuel pump issues it showed egr valve problem Eml bull out and something about the immobiliser and that's it so didn't show anything for the gearbox but there's definitely a problem with it so I'll probably end up needing a new gearbox :crazy: