1999 Discovery - transmission help?

[kndrewa]

Howdy Roverlanders!

I'm posting here to try to contact anyone who knows about troubleshooting transmissions for a 99 disco with 4.0. It's my friends, and it will not go into gear. He bought it that way and had it towed to his home in North Vancouver as a project. The shift selector moves and seems to slot into gear from the cabin, but there is nothing happening when throttle is applied in drive, 1, 2, etc. We put it in reverse and were able to get a little bit of movement, barely perceptible and only measurable in centimeters. The transmission dipstick doesn't register any fluid at the low or high hole when the truck is running, but it won't take any more fluid. He read that the fluid level should be evaluated cold with engine running after shifting to drive and back to park. It doesn't seem like there's any mechanical linkage problems.

So that's what I know. It would be great to meet someone local who is more familiar with these original discoveries than we are, and go take a look together. Or get any tips or tricks or suggestions based on what I've written here. Thanks in advance for any support!

[yrayray]

it says on the dipstick, check cold, idle and in neutral

I thought the guy said the clutch pack was gone on his truck

[landcrabmechanic]

You are going to have to pull the pan and have a look. I would suggest dropping the trans and replacing the clutches. I was going to buy that disco but no room at home for it. I am currently rebuilding a ZF autobox. They are not very complicated.

[kndrewa]

Thanks yrayray and landcrabmechanic - I'll relay the info.

My friend is interested in learning more about transmission work (or more involved maintenance and rebuild projects in general) and that was part of why he bought this one. It's good to know that this ZF auto is not very complicated! It's my first time around a Discovery of this era, and it's a cool truck - all the way down to the seatbelt weave! When we pull the pan, what should we look for? Of course I can and will look up some videos on YouTube about this next, but I'm new around here and interested in learning from people whom I might be able to meet with in the club.

About the fluid readings - we did check it as per dipstick instructions and with a result of no fluid registering whatsoever on the stick when in neutral and idling. So we thought maybe since cycling the gears wasn't actually doing anything, that the readings were not going to be accurate or that there was some relationship between the perceived gear indicated in cabin and whatever is actually going on (or not) in the transmission. I don't know a lot about how those clutch packs work or look, but if they are not doing their job and they control fluid passage through different aspects of the transmission, I will assume that is why the readings don't register as intended. A few days after I saw it for the first time and we tried the things I described in my original post, my friend tried adding fluid just to see what the story was, and it wouldn't take any.

I'll update this thread with the next phase of the situation in a few days. Thanks for helping!

[harv]

I’m not understanding why it doesn’t take any fluid when the level is low. The two most common reasons for poor performance of these transmissions are incorrect fluid levels, and poor voltage (the trans ecu is very picky about voltage). It sounds like you have a dipstick. Can you add some fluid through the dipstick?

[kndrewa]

Howdy Harv, we weren't understanding that either. My friend tried adding fluid in the manner you described from the dipstick and it bubbled over. Thank you for the tips about voltage, we will need to learn where to check and what values to expect! He bought a used transmission off Vancouver island and so we'll swap it in and report back. If there's anything to be aware of for that job, please let us know.

[harv]

So far I’ve only removed a transmission from a parts P38. I know that it’s very critical to ensure that the torque converter is seated properly. If you haven’t already removed the original one, measure the depth that the torque converter is. At any rate, when installing it, there should be 3 steps of engagement. A slight clunk as it seats each time.
The voltage I’m talking about is just the vehicle’s voltage.

[red90]

Have you looked to see if a driveshaft os turning? It could be a broken axle.

[harv]

Broken axle is a good thought. It’s what I expected on my 2A. Disco axles are a lot better, but they can still break.

[kndrewa]

Good thoughts, I didn't actually visually confirm driveshafts were rotating. Will check that and update! Great tip about the 3 stage torque converter engagement. Thank you so much for the support!