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Rover 800 825 Automatic Gearbox Oil Change

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change
Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change
Car: Rover 800 825 KV6

Years: 1996 - 1999

The Rover 825 KV6 Auto, used a 'JATCO' Automatic Gearbox. ( JATCO JF403E 4-Speed box ).

WARNING: A special Automatic Transmission Fluid (ATF) was developed for these gearboxes.
If you decide to change the gearbox oil, then you need the proper MG-Rover oil for the 'JATCO' Gearbox. Normal 'Dexron II' or 'III' has the wrong viscosity/consistency for the JATCO boxes. A 5 litre tub of the correct stuff for the JATCO Gear Boxes should be ordered, the part no is VYK000040.

Gearbox oil is supposed to be good for several years and many miles, but as these cars are getting old now, most of them will want it changing just because the oil will be so old, even the low mileage 800's, as the oil does lose its effect. If it has been changed before, then it is likely, that the fluid that has been put in the gearbox is wrong! As most garages including Rover ones would just use normal Dexron II (ATF) which is incorrect and has the wrong properties required for the JATCO boxes.

Checking the ATF levels.

It is quite normal for the fluid levels to appear incorrect on the dipstick when the engine is cold because this is not when you take the COLD reading!

To take the COLD reading, the car should have been stood for at least 30 minutes, then you start the car and allow engine to warm up.

Then (with foot/hand brakes on) move the selector slowly through all the gears (P R N D 3 2 1) allowing each gear to be engaged before going on to the next, and back to park (1 2 3 D N R P).

(With the engine still running) It is now that you check the 'COLD' level. (wiping it the first time)

You should then drive the car as normal for 10-15 minutes, to warm up the engine and gearbox.

Then move the selector through all the gears and back to park

(With the engine still running) It is now that you check the 'HOT' level. (wiping it the first time)

To Change the ATF.

After driving the car, I would put it on the ramps. Then I would sit with my foot on the footbrake and with the handbrake on before going through the gear selections and back to 'park'.

Then I would allow the car half an hour or so to cool back down (otherwise you will get scolded/burnt).

Then I would drain off what I can first, with the gearbox in 'P' and the engine off.

Then I start up the car, and move the gear selector through all the gears and back, to empty as much oil as possible, from all the sections that will empty, then as soon as the flow stops/slows right down I switch the engine off. I have never heard of anyone having problems doing this (and I believe this is what the dealers would do) as the parts all have a coating of oil, and it is not as if they were dry, but you make your own choice as to whether you choose to do this! (If you check the Rover/landrover/freelander forums, they will also talk about doing the KV6's this way)(Of course it is dangerous to run a gearbox that is dry or has no fluid, but your parts will all be coated if you drove the car before you start this.)

Then replace the bolt. I just tighten them by feel, using the correct size socket and bar, but you could torque them up, to the correct tightness if you have the tools.

When you refill the gearbox, fill it up using a funnel in the gearbox dipstick tube (surrounded by rags!). Once you start to fill it (pour slowly)(i transfer to a smaller jug first - also helps me measuring), you can then start the engine, as this should be refilled with the engine running, you can stop every now and again to go through all the gears and back to park. or if you have someone to help you, you can have them moving slowly through the gear selections as you fill it up.

When you undue the bolt under the gearbox the oil will drain out, then if you run the engine another 1 litre will drain, before you can put 3.2 litres back in. (the gearbox holds 6.5 litres but you can only drain half each time, unless you remove it and dismantle it). The oil for the gearbox is about 25 + VAT in UK for 5 litres. DON'T USE DEXRON II IN A JATCO BOX. YOU MUST USE CORRECT MG-ROVER OIL IN THE GEARBOX.

If you have drained the oil you can then add about 2Litres. If you ran the engine to drain it further you can add about 3litres. You should find this will mean you can then just top them up a little if needed, in case you are worried about overfilling. I just add 3.2litres as it is the correct amount. (the readings from the gearbox are hard to get right with the dipstick).

The Gearbox hold 6.5 litres in total! (you can not drain off this amount).


You can just do the first bit to drain the oil, but if you do, you will only be able to replace about 2.2litres (a third), so it would take forever to replace it all. If you run the engine, you drain off around 3.2litres (half). That way the next time you drain it (in a few hundred miles or so), by draining half off again you will be leaving a quarter of old and a quarter of new, so when you add a fresh 3.2 litres on the second change you will in fact of changed roughly three quarters of the oil in the gearbox. Changing a third time will take it up to seven eighths!

(two tubs needed if you want to do 2 or 3 full changes - expensive!!! ....but worth it!)

It's also worth combining changing the gear box oil with clearing the Gear Box memory, to do this you remove the left hand fuse in a bank of 6 fuses under the steering column, for at least five minutes. (although if you are experiencing any gearbox problems, you can try clearing the memory any time you feel like it).

I hope you can understand this ok! (If not here's some pics and a video to try and help you!)

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change.
After preparing a bucket, or a container (& funnel) in a bucket, ready for catching the old Automatic Transmission Fluid, use a 24mm Socket to slacken off the Auto Gearbox Sump Bolt.

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change.
With the container/bucket in place undo the bolt the rest of the way. Initially the oil comes out fast! This old oil is still looking very red, as it has been changed often on this vehicle. The longer the oil has been in the more discoloured or browner it will look and the thicker it will get.

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change.
The oil will eventually slow to a trickle, at this stage just over 2 litres has been released (out of 6.5 litres that the gear box holds!).

If you start the car, by running the engine/gearbox, it will release about another litre. This allows you to change approximately half the oil in the gear box each time you change it.

(If you try this you do so at your own Risk!).
Running the engine, allows you to drain more oil from the Rover 800 fitted with Jatco Gearbox. You can also put your foot on the foot brake and go through the gears on the gearstick. Make sure nobody else is near or underneath the car though, if you do this.

(This method is for the 825 Auto, you do not need to run the engine to drain the Gearbox on the 820 Auto.)

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change.
After you have switched off the engine, allow the oil to continue to drain until it slows to a stop.
Then wipe the area and refit the gearbox oil sump bolt back in place. (If you forget to do this, you will just make an expensive mess!)

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change.
Refill with MG Rover Automatic Transmission Fluid JF 403E (part no VYK000040). Add 2 or 3 litres depending if you ran the engine or not. The New ATF should be added by removing the Auto Gearbox Dipstick and pouring (using a funnel) down the dipstick tube.

Rover 800 825 KV6 Jatco Automatic Gearbox Oil Change.
After you add the first half, get somebody to sit in the car. Then with the engine running and their foot on the footbrake, get them to slowly move the gear lever through the gears. Be careful though, and make sure the funnel stays in the dipstick tube as you continue to pour the new fluid in.


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