Engine jumps 100 rpms for a couple seconds
#11
03-20-2010, 02:29 PM
Looked at it today and I'm very happy with it. I can move the outside of the cross shafts with my thumb, there's a little clutch adjustment indicator. The clevis rod goes into the slave cylinder about 3/8". I just have to adjust it well before the fingers move that far. Otherwise it will bottom out again and put pressure on the throwout bearing.
One thing though the little tab indicator was right in between the "clutch needs adjustment" and "normal operation" areas, right on the line. Is that ok? There's a large range of "normal operation" and a small "clutch needs adjustment" area. Do you look at it when the clutch pedal is up or depressed? I also noticed last trip my fuel mileage increased, probably because the throwout bearing was seized before. That sucker must've been getting really hot with all that friction. You couldn't move it by hand. After new friction lining has been installed, they must be worn-in to match the new surfaces together. Burnishing is a series of aggressive clutch engagements to break in the lining to the friction surface, similar to burnishing brakes. The competent installer generally does this during their road test.
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Bob H 
#12
03-22-2010, 06:20 PM
Join Date: Aug 2005
Location: jackassville (winnipeg, mb)
Posts: 3,280
Well its slipping again this time a lot worse. First it happened thursday morning, about a mile after firing it up. I was in 10th gear at full power with a full load and it jumped from 1500 to 2000 rpms in an instant. Backed off let it coast for a while then it was fine.
This was in Georgia, by the time I got to Kentucky it was slipping quite often, 200 rpms or so going up hills at full power. So I would back off to half power. I pulled into the Pilot at Oak Grove and took the plate off to have another look. This was after parking for an hour. It was absolutely blazing hot. I touched the pressure plate and if I had left my hand there for more then a few seconds my skin would've melted. So I left the plate off and made it home at half power. When I got closer to home I started testing it, and at full power just tapping the clutch pedal causes it to slip. Not even pushing it down 1/4" causes it to slip. I checked the clutch adjustment, linkage, everything again. I could still push in the slave cylinder, so it is not loading the release bearing. Took it back to the shop today that did it, and they're talking about burnishing, but seemed doubtful that was a solution. I think they did do that before. Talked to a friend of mine that knows a lot about clutches, and he pretty much gauranteed it has to come out.
#13
03-25-2010, 02:41 AM
Join Date: Aug 2005
Location: jackassville (winnipeg, mb)
Posts: 3,280
It appears as though the wrong cross shaft was installed resulting in the clevis being 10 degrees out. This causes the slave cylinder to be compressed a little too much resulting in too mcuh pressure on the release bearing and bad geometry. The clutch was also not clamping correctly, something about a sleeve moving?
The truck had an update from a vertical slave cylinder to a horizontal one, and you need a different cross shaft. A vertical style cross shaft is not compatible with a horizontal slave cylinder and vice versa. |
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