I have an 03 Disco that is not shifting into 4th gear. the fluid is full with additive. also there is a delay in engagement when shifting into reverse or drive after the engine has been shut down for a while. might this be caused by the xyz switch or just sticky valves in the trans?

 

Questions.

Is has this only started happening since its been cold?

I'm in NJ, and it would take a good 5-6 miles to go into 4th. Since temps have clawed their way back into the mid 30's, its been far less time.

Have you done any work on it recently.?

What additive have you added?

Did you replace the filter?

How many miles do you have?

Where are you located?

have you tried cleaning the XYZ switch?

And some information to help you on your journey.

https://landroverforums.com/forum/di...r-44536/page2/

 

" What additive have you added? "

No doubt, if it's the LUCAS Transmission Fix that stuff is thick as snot especially in cold weather.

 

Is it cold and how long have you had this issue? IOW did it start after it got cold?

Have yet to hear of a X,Y,Z switch causing your issue.

Possible you are confusing torque converter lock up with shifting into 4th gear? TC LU is often delayed when trans is cold. TC Lock up is dependent upon the trans temp and controlled by the trans ECU.

My D2 once moving will shift from 1,2,3,4 but TC lock up may be delayed for a couple of miles if cold (below 40 F). Folks in cold climes report many more miles miles befor trans warms enough for TC LU.

Would agree with OverRover, additives may be thick, may increase viscosity and wouldn't advise adding unless you're in a nice cozy warm area. Even if cozy is it just snake oil?
......

 

I have had this vehicle almost a year now and it has been in my garage for most of that time. I think I have had it on the road about 2 months. The trans fluid has been changed with about 6 oz Lucas additive. It has had limp mode problems most of this time as well. I have replaced the trans wire harness. This improved many of the problems I was having. It has been cold here but not bad lately.
Has about 170,000 mi.
replaced switches on t case
replaced trans wire harness
replaced trans filter
replaced xyz switch (used)
Would the trans brain cause it to not engage in reverse and drive?

 

Mine never had any delays in shifting into D or R, but would not upshift into 4th unless I was doing 55mph and let off the gas quickly. After cleaning the MAF (for a different reason), it started shifting into 4th without me having to let off the gas. As a matter of fact, it felt like it was shifting into 4th too early and staying there longer than it should have. The MAF has 50k on it so I am replacing it with a new one. After I replace my head gaskets. Anyway, try cleaning your MAF to see if that helps.

 

I've seen delays in shifting from low transmission fluid levels. If it's been in/out of limp mode have you had the codes read & checked? Did you tinker with adjusting the XYZ switch position, and is the current XYZ switch black (newer cheaper style) or tan (older more $$$ style)? Did you do a 100% transmission flush or just drain/fill?

It could be time to just try getting your hands on another HP24. They aren't that much online and sometimes you can get free shipping on Ebay.

 

The trans has been out, drained and the tc has been out and drained as well as could be. Front and rear seals replaced. All solenoids checked. Put back in, filled, xyz adjusted. The MAF has been cleaned (made no diff). The problem is intermittent usually at start up. Today I sat in the rover for 5 min or more and could not get it to engage. It was only taking a minute then would engage in gear. Now nothing. I have a second trans with 1/3 the miles. Tried it and had the same problems. So I put the original back in with a new wire harness.

 

This sounds dumb, but did you ever inspect the Transmission ECU under the drivers seat and Audio AMP? Could it have ever gotten wet? I'd pull the connectors off and inspect them for corrosion, and maybe try another Transmission ECU. If you've done all the mechanical stuff, swapped the transmission and still have weird funky electrical issues I'd certainly check it out.

 

I have checked the ECU before swapping trans. I could not detect any water damage or corrosion. Also cleaned the connections just to be on the safe side.
I just returned from an errand that I took the rover for. I got in fired it up and put it in gear... Guess what? Reverse engaged immediately.?! Took it out on the highway and 4th worked just fine. Doing 65mph at 2250rpm.
I am seriously leaning to the trans ECU as the problem.