a puddle will not stop these trucks. you just had bad luck. check the fill plug on the transmission see if the oil is milky or not, check your oil make sure it's not milky, pull, clean, re-seal and reinstall the xyz and get in and drive it like you stole it.

 

Crikey. Getting the old switch out was an adventure, the electrical connector was incredibly tight, so I removed the support bracket to give myself more slack for grip, and in cracking the upper of the two 8mm-headed bolts, managed to break one of them. Sigh. There's enough of a stub sticking out of the transmission case to locate the bracket (which, you'll recall, also acts as the anchor for the transmission selector cable) but that was an unfortunate side-effect.

Anyway the other interesting discovery was that, even though the rivets were all still in place, they basically weren't holding the case halves snug anymore, I could see the orange seal and there was some gunk within.

Once I finally got it out of the truck I could see some evidence of internal water contamination, though only partially. It's airing out right now and then I'll hit it with contact cleaner.

Separately, because I don't know how long the case has essentially been unsealed, I'm ordering a used switch from a recycler, and paying the woeful cost to overnight it so I can get the truck back on the road.

Of course to drive the truck down off the ramps I had to reconnect the old switch temporarily so that I could start the truck, and then later remove my key, but it's just dangling underneath right now.

The nut which threads onto the input selector shaft into the gearbox is also quite dirty, the threads on the shaft are gunked up too. I will try to clean them but welcome any tips or tricks beyond WD40 and a wire brush?

twj

 

you are buying a used XYZ to replace your XYZ? no point. you can clean up yours unless the contacts are severely corroded. spray the **** out of it with wd40 and clean the heck out of it and then some electronics cleaner. you can do it!

 

I went ahead and ordered the used part, I wasn't comfortable with the potential risk of having to do the job a second time if I didn't do a good enough job with the cleaning/refurbishment of the existing switch. Peace of mind, I suppose, provided the inbound unit works as advertised of course.

This has definitely been a good getting-to-know-you experience with the truck. I've been thinking about how to get the broken bolt out, given the space restrictions up in the tunnel area.

I think my best chance is to slot the shank with my Dremel. The heat of the notching may be sufficient to free up whatever crystalline corrosion caused it to seize up in the first place, and since I can notch at a right angle and then use a short screwdriver to extract the remnants, hopefully that will be easier than trying to drill a pilot hole and then use an extractor.

twj

 

Once or twice a year or so I do a good underbody cleaning... while under there I brass brush and pb plaster every bolt head that I can see, then give it a good wipe down. You could also consider some simple silicone around where the cover is loose, its cheap, wont rust or contaminate it in any way, and peels out with a fingernail or screwdriver easy enough that it doesnt impede future repairs... and keeps water out too. I also gently brass rub, spray rust reformer and some black rubberized undercoating on anything getting an orange tint to it while im under there

 

take a pic of what bolt you are talking about.

 

Not a picture, but attached shows the exact bolt which broke. The head takes an 8mm socket but the shank is what you would expect on a 10mm head. When I started loosening it, the entire bracket turned with it, which I thought meant the bolt was turning successfully. I was wrong.

There's enough of the remaining shank sticking out that it will still locate the bracket's upper hole and keep it from turning, but I'd rather get it out and replace it with a fresh bolt.

twj

 

Fixed. The new (used) XYZ switch arrived this morning, and after a bit of fiddling to get the position just right on the slotted mounting tabs, all gears indicate correctly in the dash, no blinking M&S lights, and the weirdest random symptom of all, the blinking amber HDC light, have all been restored to happiness.

The HDC light threw me for a loop because RAVE says it only illuminates on its own when the brake lamp relay has an open or short circuit. I wonder whether, with the XYZ switch disconnected, there is some fluke condition in which that relay doesn't behave as expected, so SLABS threw the error. I couldn't see anything in the logic of the wiring diagrams but I'm not an EE so could have missed it.

I did have to clean the threads inside the nut (M8x1.25, btw) since it was so gunked up from years of who knows what. I took a wire brush to the position selector shaft threads as well, and everything went back together much more easily than it had come apart.

Anyway the old XYZ switch, upon closer inspection, was evidently a ticking time bomb. There had obviously been water in its lower extremities for a while now, the copper strips at that end are heavily corroded, and refurbishing the switch would require pulling out each of the wires, thoroughly cleaning each contact, and probably splicing in new wire for fresh copper-on-copper action.

So not to say it couldn't be fixed, but I feel better about having a replacement in there.

I'll take it for a drive tonight and see if the O2 sensor has sorted itself out, but at least that one will be easy to fix if needed.

Thanks to all who offered encouragement and counsel!

twj

edit: re the broken bolt, I've decided to leave well enough alone for now, the bracket appears to be immovable and isn't subjected to any weird twisting motions I can find so I'm not overly concerned about the remaining bolt breaking off.

 

did you re-seal the xyz you just bought? some serious amounts of RTV i hope

 

No, its case was intact, no flex, no loose rivets, no audible sloshing. Even the protective loom on the wiring pigtail was still flexible and intact, unlike mine which had become brittle and fell apart.

Smearing RTV around the exterior seam without cracking it open wouldn't make for a very robust barrier. Kind of like putting undercoating on without proper surface prep, you run the risk of simply trapping moisture behind the polymer coating.

I did spray silicone in the splined hole and on both sides to get to the O-rings a little, and once seated properly it slid onto the selector shaft very easily.

twj