2/4 Brake Duty Solenoid Repair? Anybody replacing theirs?

[clf]

A while ago I was scrolling through YouTube, and stumbled across THIS video.

It details the failure that causes the thump on gearshifts in the auto box. The actual failure is difficult to see in the video, however, the middle contact strip you can see, passes through the plastic and it seems to snap at this point (it is only about 1mm across). The guy seemingly drops a splodge of solder across two of the contact strips.

I had to replace mine at the end of last year - it was before I found the video. But tonight I went out to the shed and found the faulty one, and opened it up as in the video. Opening it up was a little more difficult than I thought, but it was doable. I checked the resistance of the body and connector, which started high, and counted down towards zero I dont know why, but it was not constant.

Dropped the solder onto the two contacts (he states 3 in the video, but in the comments he is questioned about it, and subsequently clarifies two he actually does is enough). Put it back together, and took a reading, which read a steady 3.2, which is at the limits of its operational range (I dont know if I have tested this correctly - off the car, but it remained constant at least)

The only problem I have, is my box is working fine so cannot the claim in the video. And if it aint broke dont fix it, so will keep this as a spare. (besides, I changed the fluid when I replaced the solenoid - so dont want to needlessly lose any fluid or risk getting sealant into the box).

Hopefully someone needing to do this repair, will give it a try and confirm?

A word of warning though, in case you miss it in the video. When removing the cover, there is a tiny washer that comes out with it, it would be easy to lose it - mine was stuck to the end of the cover, but held itself in place with the residual fluid.

In the image below, just at the end of the white line (I cannot figure out how to add an arrow on my phone lol), the middle contact strip is the one that is broken.



this is the reading after putting it back together.

[clf]

Also discovered at the same time, was a video of the stripdown of the Jatco JF506 gearbox (albeit from a Jag) HERE

[DMGRS]

What an excellent find, especially as these are getting thinner on the ground now!

[clf]

Originally Posted by DMGRS

What an excellent find, especially as these are getting thinner on the ground now!

I think they are plentiful in the us from what I gather, as so many cars there use the same box, eg veedubyas, and jagwires lol, not to mention some freelancers too.

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[clf]

There is another solenoid that gives problems. I cannot remember which one though. The symptom is a drop in revs similar to going into lock up when cold. Again there is a video for it, but I cannot find it now. My own car does it between 3rd and 4th. But it is only when cold, and apparently it doesn't do lasting damage.

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[bl52krz]

Not to sure But isn’t it something to do with protecting the box from damage when cold, it inhibits change ups until the oil and box has warmed up. Just saying I thought I read that somewhere.

[clf]

Originally Posted by bl52krz

Not to sure But isn’t it something to do with protecting the box from damage when cold, it inhibits change ups until the oil and box has warmed up. Just saying I thought I read that somewhere.

There is an inhibition to changes, when cold, but that applies to all gears, this only occurs on the 3rd to 4th change. Revs drop by around 200 revs, then shortly after there is a proper change up. I may be wrong in this, I am going by memory, but I think it was 2/4 timing solenoid.