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SECTION 7
MAINTENANCE INFORMATION
7.2.4 DRIVE CHAIN TAKE-UP SYSTEM
Figure 7-9. Installing the connecting link
Figure 7-10. Wear groove on the slider block
The chain tensioning system consists of a torsion spring
loaded cam assembly with a slider block which takes up the
slack on the bottom side of all but the front final drive chains.
As the chain wears, the chain tensioning mechanism adjusts
semi-automatically. Under most conditions, the tensioner
cam assembly will move to the next step of adjustment sim-
ply due to normal drive system dynamics. Sometimes, how-
ever, the cam assembly can bind due to debris caught in the
area. IT IS VERY IMPORTANT TO CHECK THAT THE
CAM ASSEMBLY IS PROGRESSING PROPERLY.
CHECK FOR PROPER CHAIN TENSIONER OPERATION
EVERY 10 HOURS OF VEHICLE OPERATION, WHEN
THE DRIVE CHAINS ARE BEING LUBRICATED. Each
step of the cam takes up about 2.5 inches of chain slack (see
Fig. 7-11).
Check for proper chain tensioner operation every 10 hours
of vehicle operation.
Each chain tensioner has a single nylon slider block. Inspect
the nylon slider blocks for wear after the first 100 hours and
every 50 hours thereafter. Replace the blocks (ARGO Part
No. 603-61) when the wear groove, as shown in Figure 7-10,
measures 1/4" (6mm).
To Replace a Slider Block:
1. Remove the floor pans.
2. Turn the tensioner cam assembly in the direction which
winds up the torsion spring and push the assembly down
as close as possible to the cam follower block across the
bottom of the frame channels. Clamp it in this position
with a Vice-Grip 10CR or similar plier as illustrated in
Figure 7-6.
3. With pliers, pry the slider block off the cam assembly as
illustrated in Figure 7-13.
4. Place a new slider block over the shaft of the cam assem-
bly.
5. Using a piece of wood (or similar material) pressed against
the top of the slider block, carefully hammer the piece of
wood so the slider block snaps onto the cam assembly
shaft as shown in Figure 7-14.
6. Remove the locking pliers securing the cam assembly in
its lowest position.
7. Pull up on the cam assembly to allow it to take up as
much chain slack as possible.
8. Replace the floor pans.
CAUTION
The tensioner cannot progress to the next step until there is
enough slack in the chain. With the wheels raised off the
ground, check if the chain slack exceeds 2.5 inches. If it
does, then reach under the slider block assembly and pull up.
Figure 7-11. Chain slack required before the tensioner will
progress to the next step.
2.5”
measure at midpoint
between sprockets
