What you may need is a reconditioned box.
brianp38dse
Well-Known Member
Make sure the valve block is the improved Sonnex one as the original ones are made of cheeseium
Henry_b
Think outside, no box required.
Common issue is the reverse Lock Out bore wearing it is located at the rear of the valve body. Another among many, is fluid leaking the TCC signal circuit that causes the Reverse Lock out valve to move enough to restrict reverse. There are various places where this can happen on this box, a defective TCC solenoid is usually the culprit, it is the front most valve in the valve body. Also.
What happens at low pressure is the TCC solenoid's filter breaks up due to contact with the TCC regulator valve and debris can migrate to the Reverse lock-out bore and cause the valve to stick.
If that is the case replacing the solenoid is not going to be enough to restore reverse. The reverse lockout bore needs to be cleaned and examined for damage or wear.
At that point you might as well recon the box.
H
What happens at low pressure is the TCC solenoid's filter breaks up due to contact with the TCC regulator valve and debris can migrate to the Reverse lock-out bore and cause the valve to stick.
If that is the case replacing the solenoid is not going to be enough to restore reverse. The reverse lockout bore needs to be cleaned and examined for damage or wear.
At that point you might as well recon the box.
H
A wee bit of history for my Range Rover May help, it’s had a new Gear box oil cooler fitted, it is constantly changing gear up and down as you drove along, it was hesitant when I would throttle to overtake or go up a hill then it would change down too many gears and rev high then change up too quickly, going round a tight left hand corner or a left hand junction it would flash up with Trans Fail safe mode, then it would seem to right itself after a moment, it would drive up to a junction and when I braked it seemed to have a surge and push the vehicle forward over the junction sometimes, and then when it did previously go into reverse and I lightly pushed the throttle it would jerk constantly, when I had a trailer attached and went into reverse it would jerk even without the throttle being pressed. Sorry for the long post I just thought it may provide more info for you.
gold rover
Well-Known Member
Can't add any better than the chaps have said above. But in the spirit of full disclosure: how long/far have you driven your vehicle with these issues. It may help to assess how much damage has been done.
I got it in June and it’s been on and off problems since then up til now. In and out of a couple garages and now it’s sitting in a garage after having the converter changed, now mechanic is on about the valve block, but wanted to get advice on here. Which I am very grateful for.
Are we talking GM? By any chance?
If the torque converter had to be replaced the box should have been done along with it.
The torque converter and gearbox along with the oil cooler all share the same oil and once the torque converter or the box has a problem is usually shared as well. I.e contaminated oil.
If the torque converter has been slipping or a grinding noise. The power train needs rebuilding.
It has already been said but this is just to explain why.
If the torque converter had to be replaced the box should have been done along with it.
The torque converter and gearbox along with the oil cooler all share the same oil and once the torque converter or the box has a problem is usually shared as well. I.e contaminated oil.
If the torque converter has been slipping or a grinding noise. The power train needs rebuilding.
It has already been said but this is just to explain why.
How many miles has the car done in total?
116k
As said by others, if it's the original gearbox it's due a rebuild. Around 100k seems normal.
tomcat59alan
Well-Known Member
Don't think Bemble will touch the GM box because they are trouble.
I think it is the valve block that causes all the issues. Once that is upgraded to Sonnax it works perfectly well. The issue is it tends to bugger everything up.
I think later models had the ZF box which is solid so guess it can be done. Don't know if any modifications are required.
Datatek
Well-Known Member
The main problem seems to be the 2 stage lock up clutch in the torque converter which is designed to slip, it sheds material that knackers the box, the valve block is made of cheese which does not help.
