Hey there this is my first post to the site and I'm trying to figure out a problem with the Disco I just bought. I parked it in my driveway, on a hill the other day, I take it out of Park (transmission park) and put in reverse, it doesn't move and also doesn't roll backwards down the hill. Giving it gas revved the engine. I put it in drive and went forward 2 feet then switched back to reverse with no problem. Happened to me at work on a flat area, I put it in neutral this time then back to reverse and drove away no problem. Is this a linkage issue or am I looking at a new transmission?

The other issue I've had, and I've read several other posts on here but with no definite answer, is that it overheats only with the air conditioning on. There is no leakage of coolant and no exhaust in the coolant (i.e. head gasket issues) the clutch fan seems to work just fine and the radiator is not leaking. I first noticed it going 70 miles an hour on the interstate. Saw the temp gauge rising, pulled off on an exit and parked it. Hit the eco button on the a/c unit and turned it off, let it cool down and drove home no problem. Next day while running errands I was at a gas station I turned the a/c on and drove for 5 minutes at 40 mph started heating up, hit the econ button again, shut off the a/c and it cooled off. I have driven 500 miles now with no issues as long as no a/c runs. The air is cold and blows strong when its on though and the front electric fan runs fine. My dad owns a meineke car repair center and I'm in college. So I'm on a budget but my dad and his mechanics are trying to help me but none are LR experts. Any advice would be appreciated and sorry if this is in the wrong place

 

Place is just fine. Let us start with over heating. You can download the whole factory tech manuals and owners manuals for free in link below. Called the RAVE.

If overheats at speed, this is usually a sign that radiator is sludged up, because it just can't keep up with the heat load. You may be able to flush, but may also have to spring for a $200 plus radiator.

There is an electric fan in front of the condenser, this should come on as well when engine is hot and AC on. Important that this be working or you will overheat at idle and in slow traffic.

Temp gauge should not get above 50% (mid point). Check coolant level as well, hope you have no noises like water gushing thru pipes under dash (exhaust gas - head gaskets ; or air bubbles - loose clamps). Borrow one of Dad's scanner / code readers and see what kind of coolant temp you get at idle and at 50 - 60, with and with out AC on. If you are pushing 212F at 60 mph, there's cooling problems.

There is also a water pump driven fan with a viscous clutch. When truck is cold, and not running, spin fan and release. Should stop in less than 1/2 turn, will feel like peanut butter inside clutch. Warm up truck, turn off, spin and release again. If spins more than 1 revolution, or free wheels, the clutch has lost the silicone fluid and needs to be replaced, write up in tech section for Chevy substitute ($60).

Fans are mainly for idle and slow speed. At freeway speed, you are depending on water pump, with a good tight serpantine belt, not squealing, greasy, or glazed. And radiator fins being free of gunk mud, leaves, etc.). And radiator being clear of sludge. D2s frequently came with Dexcool, a coolant that beomes corrosive and turns to mud in time, even quicker when mixed with other coolants (topping off). Of course, a bad water pump can reduce flow as well, they usually wobble, leak, etc. So would flush radiator first.

Attached is a page from the RAVE tech manual, shows the coolant flow system. If you decide to change the thermostat (it is external, not inside the motor), order a soft spring version that is 180F. Contact Justin at Lucky8. Stock stat opens at 180, full open at 204. Electric fan supposed to come on when you pass 212F, or if AC on and you are going slow. See pix of top of stat, those small holes take hot water into the stat body to warm up stat to open. If they are clogged, stat opens later than it should. The soft spring version drops temps 10 degrees or so.

 

Well my confusion is that it doesn't matter the speed, i can go 70 mph on the interstate with my a/c off and have no over heating problems, i can be in stop and go traffic (like yesterday in 90 degree heat) and still no problems, however a few minutes with the a/c running and it starts to rise no matter the speed. As of right now I'm looking at replacing the fan clutch and the radiator seeing as how the truck is at 113000 miles. I think it could just be a combination of the two but I'm not sure (could be this and the water pump though it seems to be working with no wobbling or squealing from the pulley). My dad's mechanics tested the a/c unit entirely and it runs fine and blows hot and cold. They tested the head gaskets by trying to react fumes from the coolant reservoir with an indicator that would've turned yellow had there been exhaust in it, it didn't, ruling out the head gaskets.

The car stopping in reverse is scaring me a little, but on another forum, i was told it could just be a switch and/or cable being out of adjustment. I just don't want to have to put a new transmission in the thing.
Thanks for the manuals though, they'll be put to good use. Hopefully i can figure this out though.

 

My money is on the radiator being jacked up. What color is the coolant? Green or Orange? Also, I doubt you need a new transmission. I think its a cable thats out of alignment. If it was the transmission it wouldn't sometimes do it and sometimes not. It would just always do it.

 

The coolant is yellow/green, but the guy i bought it from changed the thermostat and coolant before i bought it so it could've had dexcool in it before, but the previous owner had the front drive shaft replaced with the grease able u-joints, seems odd they would do that but leave the poorer coolant in it, but who knows?
Thanks for the reassurance on the transmission though, I don't drive aggressively particularly because I want my car to last and i don't enjoy burning gas pointlessly at $4 a gallon, but i have ran the rpms up about 2-3 times here recently to check how it handles changing gears and its not late or sticking in any of them, so I'm hoping its just a cable.
Thanks for the input! I know i need to knock out all three items (water pump, radiator and fan clutch) but like i said I'm in college and don't have the cash to drop on precautionary parts, especially when its not cracked, leaking or wobbling.

 

Let us see if you can get the front electric fan to come on. With AC on, it should be running if these conditions are met:

 

I would offer to help you, if interested, PM me your number and I'll call. You have at least 2 different issues working.

 

The thermostat was just changed and the electric fan is running, it sucked a plastic bag right up to the grill as you suggested testing. Ill test the radiator with an IR thermometer once my dad opens back up after the holiday weekend. Though due to the 100000+ milage it probably needs it but i want to just make sure i get the root cause first before replacing anything that isn't broken.