Harsh automatic gearbox changes - Failed 2/4 Duty Solenoid

[Alan123]

Originally Posted by DMGRS

Right, first of all it's done and working well - lovely job.

Next, the How To guide....

How to change a solenoid on the Jatco JF506E Automatic Gearbox (as fitted to the MG ZT and Rover 75 models)

You will need:
- About 2 hours.
- A replacement of the solenoid you're changing (repair is unlikely).
- A clean container to catch the ATF removed from the gearbox, however I'd recommend replacing with new ATF. It'll need to hold at least 4L.
- Basic tools (10mm socket, small extension bar is useful, ratchet, 24mm socket and a breaker bar). I recommend 1/4" for the 10mm socket, and 1/2" for the 24mm socket.
- Instant Gasket. I used some Granville stuff from Halfords (the 'clear' variety).

Halfords do a great 1/4" socket set I used for the job - currently on offer for £24.99 too. Bargain.


1. First of all, jack up your car and make sure it's secure. If only jacking up one side, make sure it's the passenger side.
2. Next, use your 24mm socket and breaker bar to undo the sump plug of the automatic gearbox, making sure your drain bucket is in place. Catch all of the ATF, and once the drain is just dripping, replace the plug and re-tighten.


3. Depending on how much workspace you like, remove any items in front of and in the area of the automatic gearbox you think may be in the way - I removed both boost hoses, relocated the starter motor live connection, and the expansion tank.


4. Remove all of the 10mm bolts around the front plate of the gearbox. The bolts along the bottom edge are best accessed from underneath.


5. Carefully prise the plate away from the gearbox, taking care not to damage either the radiator or any of the solenoids with it. I'd recommend cleaning the inner surface of it - mine had a bit of 'sludge' upon it.
You'll see the following; this is the valve body:


6. You need to now remove the solenoid in question - I imagine a lot of people viewing this will be doing so to change the 2/4 Duty Solenoid. When viewed from the front, it's the second solenoid from the bottom, on the right-hand side (top one in this picture):


7. Fit your new solenoid, and re-connect it. Make sure all securing bolts are nice and tight.

8. Now the tricky part - re-attaching the front cover.
You need to be *very* careful you don't go OTT with the instant gasket, as it can cause all kinds of havoc if it starts floating around the gearbox.
First of all, clean the mating surfaces of the access panel and the gearbox.
Then apply a very thin bead of gasket around the plate, making sure you seal along the inside of the bolt holes. Once the gasket is applied, spread it out by flattening it with a lolly stick or the edge of a credit card. You should be left with a shallow coating of gasket around the sealing surface of the cover.
Line it up with the mating surface on the gearbox, being careful not to damage the newly-applied sealant. Once you've got it back in place, re-insert the bolts loosely at first, and once all bolts are in place tighten them correctly. The bolts don't need to be tight - just enough to ensure the instant gasket seal won't leak.

9. Refill the gearbox with the oil removed - if using new oil, allow the old oil to cool and then measure. Insert the same quantity of new oil as was removed, but you'll need to check the level is correct following the method at the end of this guide.

10. Re-attach all removed items, and make sure all hose joints etc are leak-free if they've been disturbed.

Before moving the car, you need to sit with the car at idle and 'run through the gears' for 10 seconds at a time while keeping the car still - this makes sure oil is distributed as needed around the gearbox.
Finally, if you've used new oil, you can now check the level is correct by removing the 'level plug'. If no oil emerges, add a little at a time until it does.

Glad uve sorted it mate and your rite it's a lovely job I done mine a while back and really enjoyed doing it.

[rich17865]

Result!

Looks quite easy really, well done

[Alan123]

Originally Posted by rich17865

Result!

Looks quite easy really, well done

It is rich to be fair it's a pleasent job to do for a change

[SD1too]

Originally Posted by rich17865

Looks quite easy really ...

Yes; it's interesting to think back to the days before an enterprising few club members dared to venture into the inside of an automatic gearbox. Then, the diagnosis was a complete rebuild at £1,500 or scrapping the car.

We've come a long way.

Simon

[mh007]

Excellent 'how to'

I think it's worth mentioning that you don't really need to drain the fluid unless the intentions are to change it (or the part that will drain !)

Just have a oil tray underneath to catch any excess when you remove the front cover.

With the car jacked up at the front (and on axle stands of course) you won't lose a lot.

As already said, good news about the availability of a gasket for the front cover too.

[pletevl]

Are all these solenoids and connections in the transmission oil ?

[mh007]

Originally Posted by pletevl

Are all these solenoids and connections in the transmission oil ?

Yes, all the solenoids (9 behind the front cover) & associated internal wiring 'sits' in the transmission fluid.

It may seem a little odd but it's designed to work this way & quite a bit different to valve chests in older automatics !!

[Dragrad]

Originally Posted by DMGRS

Right, first of all it's done and working well - lovely job.

Next, the How To guide....

How to change a solenoid on the Jatco JF506E Automatic Gearbox (as fitted to the MG ZT and Rover 75 models)
.

And now in the How To's ....

http://www.the75andztclub.co.uk/foru...d.php?t=189067

[tweek08]

which one of these is the reverse solenoid ?

[SD1too]

Originally Posted by tweek08

which one of these is the reverse solenoid ?

Vince,

You have more complex problems than a simple solenoid failure. A cracked reverse piston is the usual cause of loss of reverse and perhaps some forward gears as well. Search under user name rrobson for 'reverse piston' and you'll see how he fitted the uprated part. However, as you have found a serious fluid leak from your gearbox, the loss of drive may be due only to the resulting low pressure.

Simon