Discovery auto gearbox problem

[Archy]

I recently put my 98 Disco FXI XS into a local garage here in Dubai for service and for good order I asked them to change all the oils, including the transmission, automatic gearbox, differential etc etc, since I did not know how long they had been in there.
As an engineer I thought this was a good practice, but now I'm not so sure. The automatic gearbox worked fine before it went in but now when it has come back, there are some really weird problems which weren't there before.

1. When driving and changing down manually, either it doesn't down shift at
all, or when it does it does so very late and quite violently.

2. When selecting reverse, you get the familiar "clunk" but it is not so strong
as before and the vehicle does not move. I now have to rev the engine
quite hard to get it to pick up the drive and when it does it jerks back
violently - and usually stalls. After that I can select reverse and drive
away but the same thing happens the next time I want to select it.

As an engineer, common sense tells me that simply changing the oil should not cause this, but there is also a note in the Haynes Manual which says this is a "specialised" job and should only be entrusted to a Land Rover dealer.
I have checked the obvious, which is the fluid level and it is fine. I would suspect some kind of "Air lock" but I don't know if it is possible or how to resolve it. Any ideas????
Archy

[Disco Mike]

How many miles are on your truck?
This should not have happened by just doing a tranny service, did they change the filter, did they use Dextron3??
Mike J.

[Archy]

Hi Mike,

There is only 130,000 clicks on it and yes they did use Dextron.

Archy

[scoobymick]

It sounds to me like low fluid level
Mick

[mbruneaux]

Agreed, eithre a fluid level, fluid pickup problem. Did they replace the filter? There could be an air leak and tranny isn't picking up enough fluid.

[scoobymick]

If they did replace the filter,i suppose it's possible they haven't re-fitted the pick-up

[Archy]

They did replace the filter, the fluid level is ok. I can't see it beeing a major rebuild issue because it works fine in all other ways . I will find a place to get under it and have a look at the filter.
Where is the sensor located as the Hayne's manual is not very good on the auto transmission and I will check that as well.

Archy

[scoobymick]

What sensor do you mean?

[Archy]

Sensor means "pick-up" and I still don't know which one it is or where it is fitted.

Archy

[scoobymick]

To access the pick-up you need to drain and remove the auto box sump pan.Once this is off you will see a square silver unit (the filter) bolted to the valve block,the pick-up is bolted to this(usually white plastic).The whole filter assy is held by three torx bolts (size 27),when you remove it (more oil will come out) you should find a sealing O ring where it mounts to the block and one where the pick-up mounts to filter.
If you can let me have an e-mail address,i can send you a picture from the manual which will help explain.
Mick