td4 auto reverse fault

im starting to loose reverse intermittently...where do i start looking?

Does the display show R but it doesn't reverse? Or is there a long delay before it selects reverse, though the display shows R. Or is the display not showing R intermittently.

reverse engages,but hardly drives,it tries,but hardly moves...sometimes it wont move if it has any incline to go up,it moves a little on the flat.drives perfectly in all forward gears.

Sounds like the reverse brake band slipping. This could be a pressure problem, or a wear problem.
When was the fluid last changed?

Or have you tried to check oil level recently?

does an autobox "use"oil like an engine???i did a partial oil change a while back and set the level as per the book....it has not lost any oil through leakage...no drips...this problem suddenly occurred 2 days ago.
level check is tomorrows job just in case.

Not the auto won't use fluid like an engine can.
Did you use the correct fluid?

well ive been digging a bit deeper today...yes i used the correct fluid and checked the level today and it was correct. while i was in the vacinity i disconnected the wiring plugs and wd40 d them and refitted them .up till today hawkeye was coming up with comms error for the jatco however after the wiring was played with it did a read and said no dtcs but when i pressed the footbrake i got an error message came up.
after reconnecting hawkeye later im now getting the comms error message again??
drives forward perfectly,when in reverse it does drive backwards on tickover as long as you dont load it up..i mean try uphills or revving engine.its like a hydraulic fault where its sealing at low pressure but passing oil when you load it up.
are the brake bands adjustable on the jatco?i used to do bands on the old borg warner and gm boxes on jags years back but have no idea on this box and can find little useful info even on rave?

Disconnecting the barrel connectors then reconnecting them won't make a difference to hawkeye comms errors. The barrel connections only carry the solenoid and sensor connections, and the other one the gear lever positions. The connections need to be clean and free from things like WD40 or other chemicals.
You need to do a resistance test to see all sensors read correct and solenoids measure correctly.
You say pressing the brake made things change... use yer hawkeye to make sure the brake pedal reads correctly in the auto gearbox section. It may think the brake is applied when it's not.
If you have an older version of hawkeye software yer can get frequent comms errors in the auto section. Version 7 fixed this. the version number appears when first powering the hawkeye.
Compare yer hawkeye when reversing on tickover to the results in the vid below (click the you tube icon and it will open/play in a new screen)

Sounds like the brake band slipping. It's gripping initially, but then begins to slip under load. The slip then heats up the band, causing it to expand, so all drive is lost. It could be a blockage in the piston feed, but it sounds more like the band itself to me.

are the bands adjustable? is there a jatco workshop manual?

i am not expert on auto boxes but I believe the bands have to be replaced

if yer watch this video you'll see the reverse bands at about 28 minutes in

I knew I could count on you lord hippo

So the reverse brake band has some adjustment, at the servo. But it looks like the band doesn't use the entire surface in use. This looks like a design fault to me. But I guess it takes 10 years to show its self.

Did yer get it fixed?

did yer get it fixed?
@xamtex

Hippo said:

if yer watch this video you'll see the reverse bands at about 28 minutes in

Click to expand...

I was actually looking for a rubeer band on first play of that video!

wolflore said:

I was actually looking for a rubeer band on first play of that video!

Click to expand...

Brake bands yes. Rubber bands no. Unless yer referring to the seals.

Hippo said:

Brake bands yes. Rubber bands no. Unless yer referring to the seals.

Click to expand...

I didn't see any seals...or sea lions for that matter