D40 Auto stuck in 2nd gear

[DJX321]

Hi

The moderator of the UK Navara Forum suggested I post this question here!

I've got a 2006 D40 with auto gearbox which is stuck in 2nd gear.

I spoke to an automatic transmission specialist who said it was likely to be the ECU, rather than a problem with the actual gearbox, and advised me to go to a Nissan dealer as it has to be supplied and programmed by them anyway, and they should only charge a couple of hours labour, although the part is about £1,200 :shock: .

I have Googled it and assume he is referring to the Gearbox Control unit, and used ones seem to be available from as little as £60 on ebay. Is it feasible to just replace the unit with a cheap secondhand one? Is it a relatively easy swap and does it need reprogramming by a Nissan dealer?

I have it booked into the main dealer for Thursday morning but would be interested to know if anyone else has had this problem and found an alternative solution?

 

[Old.Tony]

Welcome to the forum.

Gear control is managed by the TCM (lives inside the bottom of the gearbox), which does receive inputs from the ECU but apart from engine load (which the TCM should be able to gauge itself anyway) there's not a lot of input from the ECU into which gear the TCM should select.

It is possible that the TCM has a fault and a second-hand one stands a fairly good chance of fixing it. That might not be the fault though - if the valving is worn or gummed up you could see the same symptoms. Same if there's been a clutch failure, or if debris has blocked some of the channels.

It might just need to be cleaned. Remove the sump, remove the valve body (which holds the TCM) and give it a good clean. Might be best done by a tranny specialist (no, not a plastic surgeon from Thailand).