Alright so here it is. 2000 Disco 2 right around 130k miles. Before going on a road trip, I changed all fluids (front rear diff, xfer case, trans oil and filter). I used factory transmission filter and liqui Moly top tec 1800 ATF (good for BMW ZF trans). It drove fine for about a week then while at the gas station after running in and grabbing a drink, as I drove away the M and S light started flashing and I went into limp mode. I then restarted the Disco and it ran fine. I got about 25 miles and pulled over and the same thing happened again. I restarted again and it drove for about 500 feet and same thing happened again so I called a tow truck and had it towed home. I left the disco in my driveway and went about my road trip in a different car. I returned a week later and went to check it out but it was back to driving normal again. I drove it around town and everything was fine. I took it out last week and it’s was doing fine on the trails (pretty technical in some areas) and about a half hour in, same thing happens again. So I tow it back home and started the diagnosis process. Battery voltage is good. cleaned MAF and seems to be good. Grounds are good. Removed XYZ switch and it looked brand new inside but cleaned anyways and reinstalled. Fluid levels are good. I was leaning towards torque converter but it drives and engages in reverse fine, and with the sitting and driving fine after sitting, I was leaning towards something electrical until recently when it totally stopped driving in Forward direction. The codes to accompany this whole thing are P0741, P0722 and P0732. I’m starting to lean towards a bad trans, but wanted to get any insight before going that route. Any help is greatly appreciated! Thanks!

 

Bad transmission is of course possible but I don’t think it’s very likely. As I think you’re aware, the ZF transmission is very good. You replaced the fluid. Make very sure that you are checking the level as per the owners manual or Rave. If that’s fine, the most common reason for limp mode on these seems to be poor electrical power. The trans ECU is very picky about voltage. Your battery voltage with the engine off should be 12.5 minimum. With the engine running it should be 13.7 to 14.2. If it was me, and the above all checked out, I would start disconnecting, cleaning and reconnecting all the electrical connectors associated with the transmission. I hope this can get you going in the right direction.

 

Check your fluid but it sounds like the new fluid finished off the front clutches, most typical failure is front clutch wearing out (a number of causes for that).

 

You mentioned battery voltage being good but are you sure the battery is fully charged?

 

yeah, I will probably drain and check the oil next. See what it looks like.

 

I’m not 100%. Just applying a little logic. The battery is a year old and voltage is good with car off and while it is running, voltage is up for normal charging. So it’s definitely speculation on my part that the capacity is good, but I will take that advice and take it in and have it checked before I start to pull the trans. Thank you

 

Ok, I'm digging up the past! This transmission issue has given me nightmares. I ended up pulling the trans pan and found a bunch of metal in there. Pulled the trans apart and sure enough all clutch packs were burnt out and there was some wear that shouldn't have been there on numerous internal parts. I ended up getting a used trans (upgraded to the 4hp24), threw that in and was getting no movement still. This time the only light that it showed was the P0722 (scanner says output speed sensor RAVE manual says torque converter slippage) so I dropped the trans swapped the torque converter with another used one, put everything back together and it still didn't work. I took everything back apart and rebuilt the new trans, ordered a new torque converter, rebuilt the transfer case, put it all back together annnndddd... still doesn't work. bought another know good used trans ($100), swapped that one with the new torque converter, and still nothing. I'm reading power to the output shaft speed sensor (2.5 Volts), but does anyone happen to know what it should be? I've read that was good, but someone else said I'm supposed to have 12v. The rave manual doesn't specify what I'm supposed to see as far as voltage goes. This thing has got me stumped and I'm trying to not just part it out at this point. Any help would be appreciated.

 

Just to cross something simple off the list, did you install the front driveshaft after putting the trans/t-case back in?
You won't be able to move unless you have the CDL engaged if it wasn't installed.

 

yes drive shaft is installed as well as CDL locked and tried with it unlocked

 

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