A very brief overview of a transmission oil change in my ’86 syncro. I had not changed the oil since I bought this van almost 2 years ago and I noticed a very slight oil leak/seep at the bottom edge of the reverse gear cover plate. I figured it would be worthwhile when I had the chance to drain the oil and look at the cover plate. I bought some regular run of the mill 80/90 wt gear oil with the idea that I would put in the fancy gear oil later after I fixed the cover plate leak. As it turned out, this was a smart move.
The oil fill port is on the right hand side of the van just above the shift linkage rear bushing. The drain port is near the rear near the midline. Important to first see if you can unscrew the fill port before trying the drain port. To get at the fill port easily I found it best to remove the rear skid plate/bars; 2 X 17 mm nuts and bolts at the engine carrier bar, 2 X 17 mm bolts and 2 X 17 mm nuts and bolts at the forward end of bars( actually there is a 15 mm nut on the upper left hand skid bar mount), and to detach the shift linkage rear bushing housing; 2 X 13 mm nuts and bolts.
Kinda silly picture of skid plate out.
Oh, I should mention the tools I used to remove the drain and fill plugs. A 17 mm allen key, and a nice Snap-On tool with 17 mm hex. I needed the allen key to help the Snap-On tool at the fill plug, there was not enough space to fully swing the wrench (you know what I mean).
And more obvious advice: clean out the hex recess in the plugs with dental pick, toothpick, compressed air, whatever. Ya gotta have the wrench make a good fit. I squirted penetrant/rust buster on the plugs, more out of habit than expecting that the damn stuff actually does anything. Next pictures shows the fill plug (shift linkage still up in place) and the wrench in in the plug, riveting story eh?
Thankfully the fill port plug unscrewed with no problem. Next, on to the drain plug. The wet spot is the penetrant fluid stain.
It too came out with no trouble. The magnetic plug had a bit of fuzz on it, but I think this is a pretty normal coif.
While the transmission drained, I removed the weeping cover plate. It seemed to be leaking at the bottom edge.
Plate off, evidence of silicone caulk as a sealant.
Close up of the bottom corner that I suspected the leak was coming from. No smoking gun that I can see, minor scratches, almost a crack like line there though, no?
At this point I was advised by my son that I need to drive him to some sort of “date”, grrr. I should have let the transmission drain overnight and degrease the mating surface of the cover plate before applying rtv silicone and re-assembling (as per Daryl of AA transmission’s advice). So I slapped on the the silicone and the plate, and set about filling the transmission. I made a fill hose with some pvc tubing and a funnel.
All filled and the skid plate back on, the shift linkage re-installed, and the damn cover plate leaks more than before. So, tomorrow I’ll do it all over, this time properly letting the cover plate area drain and be de-greased. Daryl also advised flat filling the cover plate flange to make sure it is flat.