last week I drained the transmission oil after removing the shifter stick and noticeing some condensation and brown sludge inside, no surprise as this is quite common. To remove shifter it's an easy press down and turn the collar counter clockwise a fraction of a turn with one hand.
Here is some of the sludge scraped out of the drain plug hole
PICTURE It looked nasty enough that a flushing seemed like a good idea so I removed the fill plug on the transmission and reinstalled the drain plug for now. Then poured diesel fuel in the top until it ran out of the fill plug on the side of the transmission, replaced it, and put in another half quart or so. The idea is to fill it up but not so full it runs out the input shaft which may not have a seal (later models did).
Then I let it set for a few days.
Note. It is a whole heck of a lot easier to fill the transmission from the top than it is to squeeze or funnel anything into the fill port on the side, just use that to check the level.
A week or so prior I had removed rear axle cover and took pictures of the gears in preparation for trading it for some 4.10 gears. The trade is a go so this weekend I removed the differential "pumpkin" "center section" "chunk" or whatever you like to call it and packaged it for shipping.
PICTURE Also removed the rear half of the driveshaft. Had I not already drained the rear end I could have left all that together and set the axle on jack stands to do this next part.
To help flush the transmission I wanted to run the engine and shift through the gears to get the diesel fuel in there stirred and splashed around. Without a load I don't think there is any danger of messing up bearings or bushings, diesel fuel is somewhat oily. All in all I ran it for about 10-15 minutes going through all the gears a few times while bringing the engine RPM up to normal driving speed. With that done I removed shifter again and looked inside, you can't really see much for gears or anything in there but what I could see looked much cleaner.
PICTURE Finally I drained the diesel fuel and much of the sludge with it. Except the truck was parked just a little nose down and some dirt/sludge remained in the bottom, I should have jacked the front axle up significantly for this process. So I did jack it up and poured in another pint of fuel, letting it sit and will drain it later and try to wash out the last of the sludge.
While under there I noticed the output shaft seal was wet, and I had previously steam cleaned a lot of grease off the back of the transmission. That seal number is 591448 which NAPA crossed to a new seal for about $16, one of those is on order.
Here's a little trick I thought of for the u-joints to keep them together, perhaps it's been done before.
PICTURE Used some wheel cylinder clips while removing the shaft to keep the caps on and not lose any needles.
Now would be a good time to replace the u-joints except they don't feel terrible and I want to deal with driveshafts later, so I'll reuse them for now.
Next post might be reinstalling the rear differential with 4.10 gears, or installing seat belts, or researching and thinking about replacing the wiring harness.
Grigg
