Patrol GQ Auto - RE4R03A - Missing Gears Diagnosis and Repair

[waflyer]

Hi all,

As I mentioned in my 'Member's Ride' post a week or so ago (http://www.nissanpatrol.com.au/forum...-Roof-GQ-Wagon), my recently acquired GQ Safari has lost some gears in the auto transmission .

Having not had it for very long, nor having had an auto before, I had no idea what gears it had dropped. When I bought it the oil in the dipstick looked and smelt good so in a fit of vain hope I wondered whether it was 1st and 4th that I had lost, meaning it could be a solenoid in the valve body or simple electrical fault.

Out with the multimeter and service manual I checked all electrical components (solenoids, switches etc.) against specification. All was fine. Next, I drove around checkin the solenoid feed from the Transmission Control Unit (TCU) but again the electrical side was all behaving nicely to spec. Damn!

Next, I thought hmmmm....maybe its a stuck solenoid (more hope rather than anticipation!). So, I got some fresh ATF, filter kit and valve body gaskets and start to strip down the box with it still on the truck to rebuild the valve body, but found this in the pan.....



And that signalled then end of my hopes it was minor electrical fault! lol

Looked to me at this point that some bands or clutches had been melted at some stage by overheating. It also smelled burned to all hell. Taking a peek up into the tranny sump I also notice that the reverse clutch brake band is burnt up and has no friction material left on it. This pretty much nails the problem as being a lack of 2nd and 4th rather than 1st and 4th (brake band is required by 2nd and 4th) so at least I know what I am dealing with.

So at this point I kind of know the job is going to be a little bigger than I thought. So the plan changes to this:

1 - Rebuild valve body and check all components.
2 - Remove transmission from Patrol.
3 - Strip transmission and check all parts for wear against the service manual.
4 - Order and replace the required components.
5 - Put box back in patrol.
6 - If it works again, put on a transmission cooler.
7 - Drive it for a bit.
8 - If it is still good get a Nomad valve body from Wholesale Automatics and do a DIY lock-up torque converter mod to leave me with a solid box.

Thats the plan anyway! I am going to be doing it all myself.....mainly just for the hell of it! I think I might be mad! I will update this thread as things pro/regress!