3720 Cab: Front Drive Shaft

JasonMac · Feb 14, 2013

I have a question about my front drive shaft. I lost a roll pin that goes into the coupler that slips over the spline that powers the MFWD.

So my question is, is there a hole on the spline that this roll/spring goes through? Or is the hole located on the actual driveshaft itself? Or is the pin only used as a spacer between the two splines...

The night of the blizzard, I lost my 4wd, I was very scared I screwed up the front axle.. But the next day I realized it was the shaft itself not being able to slip over the MFWD spline. Then I noticed the rear coupler near the transmission has a pin through the center, and the front coupler is missing a pin, only a bare hole is showing... Has this happened to anybody else?

hanson1999 · Feb 14, 2013

the pin is used as a spacer as you asked. it centers the coupler on the two shafts. If you didn't lose the coupler, just get a new roll pin and away you go.

JasonMac · Feb 14, 2013

Thanks... Hoping that is all it is... If not maybe a cable adjustment on the lever... I can position the driveshaft by hand and it will bite into 4wd mode... But it won't stay... I was able a few times with the wheels off the ground to pop it in and put of 4wd... But once I get using the machine, it jostles free again... The splines look okay... Definitely not completely stripped... Any other ideas?? Under closer examination it looks like the pins are intact...

JasonMac · Feb 15, 2013

One last stupid question... When you throw the lever into 4wd, is it just turning the turning the spline on? Or is it throwing the driveshaft forward to engage with the front spline?

The shaft isn't supposed to move back and forth? Correct?

charleyfarmall · Feb 16, 2013

The engagement occurs in the transmission. The coupling and shaft do not move back and forth.

JasonMac · Feb 17, 2013

charleyfarmall said:
The engagement occurs in the transmission. The coupling and shaft do not move back and forth.

Thanks!!!!!

AKfish · Feb 17, 2013

KennedyDiesel had more/less the same problem. If the pin dropped out - there might be just enough wear that the OEM pin is loose enough to just work it's way out of the hole. I'd try to use a split-roll pin that's a bit larger and drive that into the hole.

AKfish