I'm a newbie here. I have a 1999 Discovery II and I love this thing. But the more I drive it, the more issues I find with it. The most recent has me puzzled. It started out with a "slipping" in 4th gear. Mainly on hills and around 45 mph. My girlfriend was going to be driving it and said she wanted to change the spark plugs to see if it fixed it. And yes, it needed them, but I didn't think it would do a thing to it. Low and behold, the issue was gone! But about a week later, it developed a new "slipping" issue. If you start out from a stop, it will feel like it's in neutral. The engine revs, but it goes no where. Then it engages and goes like normal. It will also jump forward in reverse sometimes. And it does not always do it. It seems to have plenty of power after it does it, like there was never a problem. I am thinking the XYZ switch is dirty since that is a common problem, but wouldn't the M+S lights come on? Or is there anything else that I should be looking at. I'm hoping for an easy fix, but something is telling me this is a very bad issue... :/ Any help would be appreciated and that k you in advance!

jerm

 

could be low fluid, bad valve block, shot torque converter. Have you service the transmission lately? Heck it could be just low on fluid

 

Yeah, we checked the fluid a couple weeks ago. It was less then half a quart low. But would low fluid make it lurch forward when going from Park to Reverse?

 

It moves forward when you shift into reverse? That's sounds like a gummed up valve body

 

Thanks King Koopa, how does one go about fixing that issue?

 

You might get lucky with new fluid and detergent additive but you might need to remove the vb and rebuild it.

 

Had sort of that problem before when it seems like the gears won't change and the RPM hits really high before it kicks in for a long time. I just drained the fluid and change it and the filter too. It worked in my case, just hope its the same problem.

 

I also experienced same problem when I purchased mine, trans fluid & filter Change fixed mine as well, use MAXLIFE synthetic it has good cleaning power & withstands higher temp, when checking fluid don't forget it needs to be warmed up go trough gears & leave engine running then add fluid until it start drizzling out of fill plug, if checked with engine off then it will be about 2 quarts too low.

 

Firstly, spark plugs have sweet FA to do with the transmission playing up, believe me. It does sound like a dodgy torque converter or trans valve block but start with the simple stuff. Change the auto-transmission oil filter for a new one (probably never been done before) and refill with the recomended ATF but follow the RAVE procedure to ensure the maximum ATF fill up. If then you still have issues then start looking deeper into the auto-trans. The xyz switch is unlikely to be the cause unless you are confusing the 'limp home mode' (which is 3rd auto gear only) with a 'slipping' effect. However, the M&S lights would be flashing if in 'limp home mode'.

TIP: never let a woman drive your truck, they always create a problem with them