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1st October 2020, 20:13 | #1 |
Posted a thing or two
2004 mk1 Rover 75 1.8T Club SE saloon (auto) Join Date: Jul 2013
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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 ). I've already changed ATF fluid for the proper N402 stuff - with no change. Cheers, Karl. |
1st October 2020, 21:04 | #2 | |
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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).
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1st October 2020, 21:38 | #3 | |
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2004 mk1 Rover 75 1.8T Club SE saloon (auto) Join Date: Jul 2013
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Thanks Alan 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. |
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1st October 2020, 21:49 | #4 | |
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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.
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2nd October 2020, 00:54 | #5 |
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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
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2nd October 2020, 08:18 | #6 | ||
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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
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2nd October 2020, 19:58 | #7 |
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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! 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.
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2nd October 2020, 20:25 | #8 | |
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2nd October 2020, 20:31 | #9 |
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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.....
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2nd October 2020, 22:12 | #10 | |
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