1991 Rd-688 Speedometer Problem

[BucketTrucker688]

I just had left allentown mack and i could hear a noise under the dash. sounded like something grinding but the noise would come in and out. then i looked down and the speedometer needle was spinning around the gauge like a pinwheel. i got back home to park it for the night and realized that the mileage from my pretrip was only 5.5 miles sooner than the mileage reading when i got home witch should of been about 50-60 miles. when i recorded mt pretrip mileage it was 104407 when i went to do post trip mileage it was 104413. how do i re calabrate a new speedometer to my mileage it should realy be from new?

[Rob]

I just had left allentown mack and i could hear a noise under the dash. sounded like something grinding but the noise would come in and out. then i looked down and the speedometer needle was spinning around the gauge like a pinwheel. i got back home to park it for the night and realized that the mileage from my pretrip was only 5.5 miles sooner than the mileage reading when i got home witch should of been about 50-60 miles. when i recorded mt pretrip mileage it was 104407 when i went to do post trip mileage it was 104413. how do i re calabrate a new speedometer to my mileage it should realy be from new?

If it is the electronic type with the mechanical readout for the odometer, it needs taken apart, or run an awful long time on the bench. If it is the mechanical type it will also require the same as mentioned prior. If the 100% electronic with digital odometer, these are calibrated on the test bench with the mileage being "burned" into an eprom chip.

Rob

[theakerstwo]

This noise in the dash reminds of something i have not tought of in 30 years.In the late sixtys i worked at the freightliner dealer here and one night i go on a service call in the shop pick up. Its a jeep pick up. The speed o meter had been making a noise for some time but that night just as i go down the st and over the RR tracks the a speed o made a awfull noise and i look down and in front of me the speedometer and half of the dash goes down to the floor and hits my feet. This is one of those flat dashes but as it does it all of the dash lights go out and at the same time the trans starts to make a noise. I stop and gets my light out and found the trans tail shaft had locked to the drive shaft and broke off and wound the speedometer cable up around it like a winch pulling the speedometer head down to the floor.We drag it back to the shop and it looked like the trans had not had oil in it for a year. So watch out for the noises in the dash.

[Rob]

I won't tell "Momma" about this episode. She is likely to think of a way to pulverize my skull with a speedometer head hanging from a cable.

Rob

[BucketTrucker688]

i heard the noise in the dashbefore but it was infrequent and i couldnt really tell what it was. the speedometer never really worked right for awhile now as soon as you would start to move it would go up to 40mph then stay there until i stopped regardless of what speed i was actualy doing. where can i get a new speedpmeter head for it and is there a way to switch the mechanical to a electronic head. i want to switch all my gauges to the teltek digital gauges eventually. i would change to a digital speedometer now if there was away to convert it.