MBF Posted March 6, 2013 Report Posted March 6, 2013 Well, after 6 months of work I put the 49 on the road today and took it on its maiden voyage. It's been a fun project so far cleaning up the vehicle, replacing a lot of the wiring harness, water pump and converting it from a dump to a flatbed. The shakedown went well-I made it out and back unassisted. One thing that surpised me is the speedo. I removed the two speed mechanism on the back of the speedo (wasn't working) and connected the cable directly to the speedometer drive. Going down the road, it appears that the speedo is reading a bit slow, but the odometer is accumulating miles like crazy and recording tenths as miles or maybe even more . I have other units on the shelf, and opened one up to see what is in there. I don't see what is causing this. I'm inclined to replace the speedo, but I really don't want to as this truck was a former firetruck that obviously has low miles on it. I did check the 2 speed drive unit when I removed it and it appears that in high range that that it is very close to a 1:1 ratio, which is why I figured I'd be okay hooking the cable up to the back of the speedo. Any suggestions as to what could be causing the slow read on the speedo and the high odometer readings? Quote
Dodgeb4ya Posted March 6, 2013 Report Posted March 6, 2013 Why dont you take the speedo out and temporarily hook it up to the cable in your other truck and test drive it to see how it works in the 1 ton? Quote
Dave72dt Posted March 6, 2013 Report Posted March 6, 2013 Does it appear to be more accurate when in one range than the other? Quote
MBF Posted March 6, 2013 Author Report Posted March 6, 2013 No-the two speed mechanism behind the speedo was removed. I'm concerned that the speedo appears to be reading slow, but the odometer is recording 12 miles on a known 2 mile run. I walk that route every day so I know it's 2 miles. I don't understand how the odometer could be running so fast when the speedo isn't. I'll be changing oil every couple of weeks if I rely on this speedo. I dismanted another one and ran it with a drill and I don't see why the odo is running so fast. I wonder if the 10ths indicator is seized to the last digit of the miles indicator? Does that sound possible? Quote
wallytoo Posted March 6, 2013 Report Posted March 6, 2013 I wonder if the 10ths indicator is seized to the last digit of the miles indicator? Does that sound possible?. . wouldn't that be relatively easy to check? drive it a short distance, and see if the mile digit is turning the same as the 1/10s digit? Quote
wallytoo Posted March 6, 2013 Report Posted March 6, 2013 also, what range were you driving in? without the adapter, the speedo won't read correctly in one range. . if you were in high range, but the speedo defaults to low without the adapter, the speed indicated would be lower than actual. of course, the odometer should then read slower, too, unless the digits are stuck together. Quote
wallytoo Posted March 6, 2013 Report Posted March 6, 2013 o, but I really don't want to as this truck was a former firetruck that obviously has low miles on it. I did check the 2 speed drive unit when I removed it and it appears that in high range that that it is very close to a 1:1 ratio, which is why I figured I'd be okay hooking the cable up to the back of the speedo.. . ok, another post. i was thinking that the adapter does just the opposite. when in low range, it runs 1:1, and when in high range, it runs at a different ratio. my speedo works much better in low range. in high range, it bounces around a bit, and sometimes drops to zero, but seems to read lower than actual speed. Quote
ggdad1951 Posted March 6, 2013 Report Posted March 6, 2013 congrats on the voyage....maybe you are missing the flux capacitor? Quote
Dodgeb4ya Posted March 6, 2013 Report Posted March 6, 2013 Is the diaphram broken in the adapter? Wonder how many miles are really on the truck? Quote
MBF Posted March 6, 2013 Author Report Posted March 6, 2013 Not sure about the adapter. He had the actuating lever held over by a loop of wire that had slipped somewhat so whatever range it was in it wasn't doing anything. Seems like one set of gears is worn, maybe because it wasn't fully engaged. I haven't messed with the adapter. I was working to get rid of the oversized dump body he had on it, and get the flatbed installed and cut down. There is good vacuum to the unit that I blocked off when I removed it and hooked the cable direct. When we get through this last round of snow we're supposed to get today I'll dig into it further. I know the speedo in the 1 ton is almost right on, so my son and I are going to take both of them out this weekend with another speedo head and see what that shows. The cable was a NOS unit I installed when I removed the adapter. Thanks for the suggestions guys, I've never seen a weak flux capacitor -they're usually either good or bad. Quote
Dodgeb4ya Posted March 7, 2013 Report Posted March 7, 2013 For those who do not know what this 2 speed speedo adaptor thingy looks like.... Quote
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