losing reverse in 1UZFE A341E transmission, intermittent fault, help please

**rxtoy** · 23-04-2016, 06:20 PM

so i bought a fairly cheap 1UZ swapped hilux a few weeks back, its stock all round in regards to computer, engine and transmission, although the traction control is not hooked up, and its running a speedhut GPS speedo

box is an A341E

my main issue is that it has an intermittent fault where it will not engage reverse. it had an ATF leak when i first got it, so i removed the trans sump and filter, gave them a good clean, fixed a couple of bent spots in the mating surface of the sump, and refitted it. also filled it with new ATF as the old stuff was looking a bit grotty.

it seemed fine for a week or two, then the fault restarted. its only temporary, and does it both when cold or hot. it just feels like the selector is going from park straight to neutral, there is no drop in revs, no audible click from the solenoids, or any other sign that it is going past reverse. i have tried disconnecting the plug to the gearbox when the fault is present and there is still no reverse.

pretty annoying when you have to push it out of carparks.

any theories i can test before i replace the gearbox? its only done 150,000k's apparently, so i wouldn't expect it to need a rebuild at this point.

any help appreciated,
cheers
Matt

**allencr** · 25-04-2016, 04:46 AM

Drain the converter, else you've only changed half the oil. IDK if yours has a drain, but look or just drain & fill again, 1/4 old stuff left in it seems to be acceptable.
Find a wiring diagram, & put 12v to the trans solenoids that are on for R or just do all of them a dozen times. Do they all sound similar, nothing much different or sticky/slow/delay response to current?
Clean the valvebody?
WHAT WAS in the sump & filter!!!!!!
How many times do you try it when it happens, and run through all of them?
"pretty annoying when you have to push it out of carparks." Or push it in, drive it out.

**petergoudie** · 16-06-2016, 12:49 PM

Find an old desktop computer and pull out the leds along with their long leads. Strip the wire ends and slide them up inside the gear change computer contacts. Drive the vehicle and see when the leds turn on and off, and check that with the workshop manual sequence. If the correct sequence of lights does not show up it is the vehicle's computer.

If the correct sequence occurs, it can be a clogged filter. When you have the pan off look closely at the solenoids. The solenoid earth is soldered to the outside of the body and I had one where the solder had cracked but it was only evident with a magnifying glass. Fixed it just with a soldering iron.