I have not posted because I have nothing to post till now.
My truck runs perfectly every day till yesterday. In doing a septic
system I & son went to rent a bobcat, this was yesterday. First of
anything over 45-50mph my speedometer go bonkers, like its reading
90 60 30 80.The cable & casing was replaced last year, and I keep it
well lubed and oil the wick, it turns smoothly by hand. Now we leave
the rental to go to the job, next the rear axle goes into neutral, done
coast to the side of the road, put the button down and we take off like
I had a bad dream. Third, I now have to go back to my yard and get
big Bertha, a 38,000lb bulldozer., speedometer still crazy now I look at
air gauge 150 and the blowoff valve starts to spit as it should so I now
know the air governor craped . Oh this is on a 1954 F900. Today Sunday I
will try it again. I'll bet it will go perfect. does anyone else go through
this evil posessment or did I have to many beers and had a bad dream.
question is what would make speeometers spin up and down, I even
drove while feeling the cabel it goes around perfect and does not spin
up and down.

 

I'd pull the inner core out and see if it's kinked or frayed. This will cause that problem. Also, a bad speedo head will do this. These early heads wear out over time. There's a shaft in the head that goes from side to side across the back and the gear on one end wears. They'll also screech over time as the wear gets worse. Almost forgot, check the driven gear where the cable attaches to the tranny, these will get dished and not always catch the drive gear in the tranny well. While you have that gear out, try to see what shape the drive gear is in. Tough to do in the truck! If your speedo gears and core are ok, then, I'd replace the speedo unit. THere's plenty around and fairly cheap.

Barry

50 F-1

 

been a while,but on a two speed rear end,does something in cable shift to compensate for two different gear ratios RED

 

You are not alone by any means. One day my L8000 quite charging (broken wire on the alt.) so no heater or signals, the pto cable stuck from the freezing temps and rear brake drum stuck on (again from the temp). Made for a long day hauling snow.
The rest of the time this is a great truck, just didn`t like the cold that day.

 

Thanks, all set, the air problem was the line to the air dryer and I cleaned the
wire connector to the motor on the axle and put some more oil in the speedometer
little hole in the wick we will see today. sam

 

All problems taken care of of course a new speedometer it was not the cable and the
rear axle needed a new harness. done works fine sam

 

Im Sorry I Dont