I have a 96 discovery. I got it buried up to the frame in mud and while trying to get it unstuck smoke started coming from the right side. (leaking coolant) When that happened it will no longer engage in any forward gears...4wheel or all wheel.It will go into reverse.It is still stuck in the mud and I spent all day digging and got it moved about 5 feet.Hopefully ewill get it out tomorrow.I popped the hood to put coolant in and 2 of the spark plug wires have melted.

Any input on these issues? (the plug wires and not engaging in any forward gears)

 

Wow, you really rode it hard didnt you?

Sounds to me like you overheated the tranny and burnt it up.
Check the trans fluid level, top it off if you need to.
It is always in 4x4 mode being a full time four wheel drive truck and all.
You will need to replace the plug wires.

 

chances are like spike said, the transmission is fried. I would do a complete flush to see if you can resurrect it. Spark plug wire might have melted because it was submerged...? maybe... idk for sure. What type of spark plug leads are you using? Good luck to you, and I hope its not as bad as it seems.

 

Was easy riding till I just sunk in the mud.The way it was explained to me it has AWD and 4wd I use the differential lock to put it in 4wd and the 4wd light comes on.I was just rocking it back and forth to try and get it out.Granted I had the accelerator pegged to the floorboard,then let off to switch from drive to reverse.

I forget what plugs and wires I put on it last.Was about 8k miles ago.

 

No that is NOT correct.
It is a FULL TIME FOUR WHEEL DRIVE WITH A HI/LO TRANSFER CASE THAT IS LOCKABLE.
AWD uses clutches to distribute power to the wheels, full time 4x4 uses gears, there is a HUGE difference.
When you lock the t-case you are locking the front and rear driveshafts together so they get equal amount of power.

 

Your truck is full time 4 wheel drive not all wheel drive. You can lock your center differential for better traction.

 

ahh,what's the different settings for the differential lock? I got 2 lo selection and 2 high selections...one is when you pull the stick to the right then when I use the low or high on the left side the 4wd light comes on...

 

You can lock your center differential in either high and low gears. The symbol is not a 4wd symbol it is a diff lock symbol.

 

Forward and back on the right is unlocked.
Forward and back to the left is locked.

SO when driving in mud you want the transfer case shifter to the left and forward.
You really need to understand your truck before you take it off road.

 

Finally got it out of the mud.The plug wire melted because the heater hose above it had a hole in it and it was leaking directly on to the wires.

Checked the tranny fluid,it was full.Got it towed back home.WAiting for the mechanic to give me a price to fix it.It still will not engage any forward gears