Okay I have a wierd issue. I was going down a dirt road and hit a small mud puddle. No big deal, then it suddenly stopped pulling, like it was in neutral. Then the M&S lights came on and went into limp mode. Got home, put it in low and manual and then it was able to go to first if I selected first. This was after clearing the codes. Now if I put it into drive, 3, or 2, it will not move and then it will go into limo mode. But if I select 1st gear it will go into gear. Then once I'm rolling at a speed high enough for it to shift to second and then put it into second, it will go to second after I let off of the gas some. Same thing if I shift from first to drive after I get going. When I lift and shift from first to drive it will shift just fine. When in drive and I come to a stop or below 5 mph where the transmission would shift back down to first it will not move and there is a faint whirring sound. If I select first it goes right into gear and then I can lift, hit drive, and ut will upsiift just fine, as well as kick down, with no slippage at all. Torque converter locks up liknit is supposed to. If indont selwct firsr it will just sit there until it gors ibto limp mode (m&s lights on) So I'm wondering it this could be the xyz switch or bad shift solenoid (s). My scanner won't read the transmission codes, and the M&S lights go away on the next start. Also the chime like the hill decent control sometimes comes on when I start it. It goes ding ding ding ding (4 times I think) but no dash lights come on. This also happens when I hit a bump, sometimes when I turn my lights on or my wipers. Sometimes when I turn my lights on, wipers on, or honk my horn I hear the beep amd my radio turns off. When my key is in 1 or 2 position the dome lights get really dim especially if I turn my lights on. I replaced the alternator and battery with a battery from an 18 wheeler. When in turn the key to number 3 on position) everything lights back up. This is a separate problem but has me wondering what could cause that. The charging system is tup top, because in have a jbl amp thay pushed well over 1,000 watts rms and even cranked up hard the lights don't dim at all when the bass hits so I know I have more than adequate power from the battery and alternator. I don't think these are related to the transmission issue but wanted to bring them up as well. Sorry for the long post.

 

Knowing the year of your Discovery might help...but...I'd definitely get underneath and check both of the transmisson electrical plugs, especially the xyz plug. Disconnect both plugs and spray them with WD40 (female and male ends...and down inside the xyz switch itself), this will help remove any moisture or water from the connections and xyz switch. While unpluged, look into each connector to be sure all female terminals are securely in place, too.

As far as the charging system question goes...between the spelling, grammar and explanation...I'm not sure what your after here or what the problem would be. A good start is always...cleaning the battery terminals and having the battery checked by a professional, new or bigger...doesn't always equate to "good".

Good luck.

Brian.

 

Sorry for the horrible grammar. I'm typing from a cell phone. Anyway I have new terminals, new battery, new alternator and ground strap from the engine to the firewall. I am going to check the connections on the fuse block and see. It's iwerd, because when the truck isn't running, the dome lights will get dim, especially if I turn on the lights or lock the doors. When the key is on the on position everything gets bright again. I'm stumped, u less my ignotion switch is bad and not making good contact in the off and acc. Postition. Thanks for the help though. I plan on pulling the xyz switch and starting there. Oilfield keeps me busy so it may be a couple of days. I pull 100-130+ hrs a week at times.

 

Figured that was the issue...just made for some might tough reading. No, biggy.

If the key is off and the dome light goes dim...it really shouldn't be the ignition switch that is the problem...when it's off...it's out of the equation. I'm not sure how the door switches work on the Discovery, but on "most" vehicles...they are the ground for the dome light. Power runs to the dome light always and once the door is opened...it gets grounded. So, if this is similar to how the LR works...go to the door switch and clean or replace those. Turning on the ignition...may...put a tad more juice to the light and help over come the bad ground issue.

That's where I would start.

Oh, part time are ya.

No, serious...that may hours would kill this old dude...probably twice...lol.

Good luck, and be safe out there.

Brian.

 

pulled the xyz switch and it was in pristine condition, bit I cleaned it all out anyway with some electronics cleaner. Re-installed and same thing. Won't go into gear unless I select 1st gear. Once I'm rolling and go up to 2,3, or D, it wI'll Rev then go into second, then it shifts fine up amd down from there. However, if I'm going slow enough to go into first, or kick down into first from low speeds, it just revs uo and doesn't go into first until I select first. Only thing I can come up with is that I have a bad/dirty plug, or a bad solenoid. I got a transmission filter kit, so on my next days off i will change the filter and fill with Dextron III amd a quart of Lucas Transmission fix amd see what that does. It has to be an electrical issue though because everything shifts fine once I get up to a speed high enough to shift up to D (over 10 mph).

 

Okay, after digging and digging, I found this:

http://blog.paddockspares.com/zf-4hp22-automatic-gearbox-frequently-asked-questions/

This looks like some valuable information, and it seems the sprag clutch is bad, which means I get to rebuild my 90,000 mike transmission that I serviced when I got the vehicle with 83,000 Mikes on it. Odd, because my last Disco wa bought with 64,000 miles on it and when I sold it with 140,000 miles it had no issues. Oh well, good thing I have a spare parts car lol. Thanks guys for all of the responses. Now to track down this low voltage issue.

 

I don't think there is anything mechanically wrong with your trans. It would be too coincidental with the water puddle, lights dimming, and then the trans fault most commonly associated with a low charge issue. I think your problem is still in the charging and/or electrical. If your trans is full of fluid and you haven't done any major towing, it's highly unlikely there is any internal damage unless it has been overheating and not flashing a warning lamp. I would stick to the basic deductions, Mr Holmes.