Disco 2 Auto transmission - no power forwards no problem backwards!

I am totally new to automatic boxes and all that it involves so please can some one give me an idea of how to proceed , the head gasket change all went well and the engine runs fine however I have no drive (forwards)
Very very slow on the uptake when driving and feels like the hand brake is on even with the accelerator fully to the floor there is no power or kick down.

Before the HC change it was driving fine.

If I park in neutral the engine will rev and it drives fine backwards.. really ..
Is this an electrical thing like did I break some plug, wire.
Could it be the turbo (waste gate I have heard) that not kicking in?
Transmission fluid , I have seen that if the level is low the viscous clutch will not work.

Could it be that as it has stood for over a month that the transmission fluid has drained down from the clutch, a couple of months ago I did check the level by removing the plug - the fluid poured out almost under pressure and I only had 2 liters that I could put back in but it drove fine afterwards ....

Is this where i give it to my local garage and get them to read codes ..
A bit lost really and need some help as where to start

Simon

First thing when you took out the level plug was the engine running?
Fluid needs to be topped up following the procedure. top up till fluid comes out the hole, run engine and top up again, then run through the gears and top up again.
Check this first.

Does it drive if you put it in 1 not D?
Easy stuff first before condemning it

J

For a kick off, there is no viscous clutch but there is a torque converter.
And just to clarify a tiny lickle bit of what @marjon said, you have to top up the gear box with the engine running. (Sorry @marjon if you think i am treading on your toes.)

I have had to do this regularly for over a year until I finally got the leak fixed.
It is best if you can do it with someone else in the driving seat, but you can do it yourself. Here are the finer points and once mastered you can do it in about 20 minutes!
Loosen the plug but not so it leaks, get into the car, start it, Handbrake full on and foot hard on brake, put it in each gear for a second or two so that each one fills with fluid, leave it in P. You can do this twice if you like or leave it in each gear a bit longer if you like.
You have now filled the torque converter and the gears have as much as they need in them as well.
Get under the car, remove the plug, and "put fluid in till it runs out".
HOW you do this is tricky.
I personally have a pump up garden sprayer,
Like this one

I pressurise it before I start, having removed the spray end off the final tube. I then take the pipe and trigger with me under the car and trigger it until fluid runs out of the box. I can then quickly drop it and put the plug back in.
I tighten it right up after I have turned the engine off.
It is a barmy way of having to do it, but there you go!
Best of luck.

marjon said:

First thing when you took out the level plug was the engine running?
Fluid needs to be topped up following the procedure. top up till fluid comes out the hole, run engine and top up again, then run through the gears and top up again.
Check this first.

Does it drive if you put it in 1 not D?
Easy stuff first before condemning it

J

Click to expand...

No it was not running ..
Yes it will drive in 1st but only very slowly
My main concern is that i did something like not properly plugging in loom connectors properly .. but i guess it wouldn't run right?

Simon Perks said:

No it was not running ..
Yes it will drive in 1st but only very slowly
My main concern is that i did something like not properly plugging in loom connectors properly .. but i guess it wouldn't run right?

Click to expand...

I think you'll find your main concern is that it is running with only half the ATF in that it should.
See posts above.

Get the fluid sorted first. @Stanleysteamer did add a bit more to my explanation that may not have been apparent at first. About the engine needing to be running after the first topup then plug back in before switching off.

Simon Perks said:

Yes it will drive in 1st but only very slowly

Click to expand...

That could point to another issue but get the level sorted first.

J

Yahoo! after the service and the fluid change, also did all the filters, both oil, fuel , air and so on and she drives fine, next job that waste gate issue , i'm going to just bypass the modulator like on the defender .. thanks guys