Back in the shop....
Last summer I combined 2 of these trucks to make one good truck. Unfortunately,
a former minor problem became a major problem, appearing to be an intermittant engine missfire, or possibly a backfire. It took
a long time to finally isolate the real issue: the 4x4 transfer case gears. This is an exceptionally rare problem, which is why the experts
were at a loss to diagnose it. The problem first showed up 5 years ago only under very heavy load, then over the years it became
more frequent under lighter and lighter loads. But it was never as "violent" as it became after I rebuilt the truck last year. Well
part of the rebuild included an overhaul and reconfiguration of the automatic transmission, making it much firmer, and the shifting much quicker.
Apparently this made the gear jumping in the transfer case feel stronger...
Here's the main problem: notice the worn edges circled on the 2 gears. The groove with the line
drawn in it is used to move this gear into and away from the matching gear.
And here's the part that fit into that groove: The upper one still looking new, with the plastic
spacers still intact. The lower one was the trouble maker, the spacers were gone, and even half the metal was worn away. This allowed
the gear to move in and out of position all on its own, and caused the gears to skip under load. It also allowed other parts to move about...
And damage this, the oil pump inside the 4x4 gear box. There should be 4 positioning tabs around
the perimeter, and these have been sheared off, and the oil intake port has been ground down to almost half its original
This is what the pump should look like...
I do have a spare parts 4x4 gear box on hand, but there were some slight differences (it's electric shift, not manual shift), so the
parts were not completely interchangable. These are the 2 matching corresponding parts, and you can see the gear teeth are good on the
other one, but its length is too short. Oh well, the spare parts gear box did provide the good oil pump, and some other bits. The rest are on order
and should be here soon. Then I can put it all together, and move on to the next possible issue!
Now how did those Lewisia get in here ???
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