Jatco solenoids
 

Has anyone ever changed all 9 solenoids in one of our Jatco auto boxes (JF506e)?

I bought a full set from the US some years ago and am only now considering undertaking the process.

However, I've read (somewhere on here) that there's a bolt that can disappear into the valve body when slackened off (to remove one of the solenoids near the top of the solenoid bank).

I know DMGRS has done a guide on changing the 2/4 brake duty solenoid (near the bottom) and this seems to be a fairly straightforward procedure, but are there any other potential pitfalls to look out for - or any other tips?

Only reason that I'm considering changing the solenoids is that the auto box in my 1.8T seems to change up from 3rd to 4th and from 4th to 5th far, far earlier than it should, especially once it has warmed up - leaving the car well below the natural torque/power curve for acceleration (even for normal driving). Maybe one of the shift or timing solenoids might affect this..? (I know nothing about the workings of an auto gearbox, btw :getmecoat:).

I've already changed ATF fluid for the proper N402 stuff - with no change.


Cheers,
Karl.

Have you tried resetting the gearbox ecu? It adapts to your driving style. Something I doubted until I disconnected the battery for a while(removing the gearbox fuse will do the same thing, without having to reprogram the radio etc) and it behaved differently. However it should adapt over time anyway to your driving style anyway, it will just be less noticeable.

Another thing to try, is the sport mode. Then once into fifth, or you are cruising, you switch it back into neutral. Sport mode holds gears for longer, and prevents lock up in fifth when cruising.

Have checked the resistances of the solenoids? There is a list somewhere on the forum with their values (I am assume you have seen this if you saw DMGRS's how to? - if not, let me know and I will hunt it out, or someone else will be along with it).

Try the above before going drastic. I may be wrong, but I believe the bolt you refer to, is on the outer casing, and people mistake it for a fill point. As far as I recall the solenoids are accessible from the front cover, and since you obviously know where the drain and fill points are, I wouldnt be concerned about the bolt you refer to.

To remove the cover, it involves removal of a lot of bolts, so if you can get an electric/battery ratchet, it will save your arm lol. Have some good quality sealant, or maybe the solenoid kit came with the cork gasket. I did get the gasket, but to me, the sealant seemed to be a better looking seal. Obviously make sure everything is clean if you do remove the cover.

There are a few videos around for this

HERE and a 2/4 duty repair video HERE which I did myself (although I havent tested in the car, but it tested correct with a multi meter).

Thanks Alan :bowdown:

I've had the battery out most of the time for the last year or so and the gearbox still hasn't unlearned it's annoying habits..!

I'd also checked the resistance of the solenoids a few years ago and they were all within stated tolerances at the time - although I expect that a poor reading would only display if there was a complete failure of a solenoid? As opposed to a "sticky" solenoid, for example (again, I'm speculating wildly here!).

I know there's a bolt on the outer casing (underneath) that is mistaken for the level plug sometimes and which can cause serious damage if undone - but I'm reasonably familiar with the outer architecture of the box now, having done ATF change etc. in the past. Under the gearbox faceplate (where the solenoids are), I'd heard there was a "captive" bolt that can disappear into the valve body behind the solenoids when you undo the nut to remove one of the solenoids (can be a pig to get it back out with a magnet, from what I understand).

If it wasn't for that, I'd be happy enough to give the solenoid change a go, and I have the gasket :)

Any info that can be shed on the subject is welcome.


Cheers,
Karl.

I only changed my 2/4 duty solenoid, as it had started thumping. Thankfully I had a replacement in the shed. Check the sport mode out and see if that makes it more to your taste. I wonder if it is meant to be like that. Sport mode on mine, is a quite a marked difference, but with the torque of the diesel, it gives that push in the back lower down the rev range. I imagine the petrol would not have that until higher up the rev range (which is obviously where yours is maybe missing out with the early changes).

I had thought the bolt was on the outer casing and had something to do with holding the reverse gear. Thankfully mine was only the 2/4, or else I could have went in gung ho and done some damage lol.

Here are more videos for dismantling the gearbox, as it is relatively common in the US in Jettas, Freelanders and XTypes.

Having done the 2/4 brake duty solenoid on my v6 I would try avoiding messing with the gearbox again because access on the V6 is horrible but probably not as bad on the 4 cyl models to me what you describe sound more software related than hardware does it shift smoothly through all the gears ? Because if you had failing solenoids I'd expect harsh shifting and more drastic symptoms than just shifting in the wrong rpm. I guess what I'm trying say is to make sure you eliminate any other potential issue before changing all the solenoids and finding you still have the same problem

:wot: :iagree:
Hi Karl,

Believe it or not, engine tune affects the performance of automatic transmissions so I would start with a comprehensive service and inspection leaving no stone unturned.

The other strong possibility is the "adaptive" software mentioned earlier, particularly if you've been driving the car gently recently. Try changing your driving style from now on and see what happens.

Simon

I've just finished changing all 9 solenoids on my diesel. Not a great job, but actually not that bad either. It's those 20 10mm screws that take the time. I have a right angled air ratchet which certainly helped.

Usual symptoms, harsh gear changes, so despite all the ohmmeter readings being in the correct range, I was confident it could only be the 2/4 duty solenoid. So I changed it for a brand new one. Absolutely no difference! :duh:

I purchased a secondhand set of 9 solenoids from a known good gearbox, and changed all of them, except my new 2/4 duty solenoid. Bingo! All fixed. :}

HERE is a video that might be worth looking at, if you retained your old 2/4 solenoid. I did this to mine, it went from a falling resistance ie. it started within range, and gradually and continually dropped out - dont know why, but it was as though the contact from the meter was being slowly pulled away from it. Once soldered into place, it showed a solid resistance and back within range.

Thanks, yes I've seen that one. The problem is, it wasn't my 2/4 duty solenoid that was the issue. My one, my brand new one, and the secondhand one, were all showing 0.3 ohms. One of the other solenoids must have been failing, but not showing anything on my meter.....

I knew that, but it was to offer a how to, to visibly check it, in case it was part of a collective problem, rather than the problem.:}