8.3C and Speedo Problems..........

[CumminsPuller]

I am not sure where these speedos get their pick up at. But I just bought an 1997 FL-50 with an 8. 3C Cummins coupled to a 9-speed Eaton Fuller. Are these speedometers mechanical or electrical/computer driven? The speedometer now is about 8 mph off on the low side and fluctuates quite a bit. Any ideas where to start looking.



Jason

 

[bmoeller]

Probably a magnetic pick-up. The magnet should be screwed in at the rear of transmission. Just above the driveshaft yoke. To remove it, unplug connector, loosen jamb nut, and unscrew. Make sure to keep track of how far in it is set at.



If there is oil in the connector, spray some electrical contact cleaner on the connections to clean them out.



If it is off on the low side, I would think it should be off on the high side too.

 

[CumminsPuller]

bmoeller,



Thanks for helping out here... ... When I said off on the low side, I merely meant I asked a guy on the CB how fast he was going. He was moving about 7-8 mph faster than I was. So is it possible that maybe the magnetic pickup is not screwed in far enough to keep a constant signal?



Jason

 

[bmoeller]

Originally posted by CumminsPuller

bmoeller,



So is it possible that maybe the magnetic pickup is not screwed in far enough to keep a constant signal?



Jason

I kinda doubt it, since you are getting a signal. I could be wrong, though. Possible wiring problem, if it is jumpy. Maybe a bad speedometer.



Could be someone put a different size tire on it also. Either that, or from your other thread, you said it had had a 7spd. The calibration could need to be changed for the transmission, in case there is a difference in the tone wheels.

 

[CumminsPuller]

Good point. It has been probably 5 years ago when it got switched to a 9-speed. But I will check in to your suggestions.



Jason

 

[HoleshotHolset]

You bought it!



Matt

 

[A Johnson]

When you pull the mag pickup, try to move the tone wheel with a skinny screwdriver to see if it is spinning on the shaft. I don't believe they are keyed to the shaft, just a squeeze fit. Also when putting the sensor back in, run it down till it stops on one of the tone wheel teeth and back it up 1/2 to 3/4 turn and that should do it.



A Johnson

 

[CumminsPuller]

Matt... ... ... I did buy it !!! Yesterday I changed the oil and filters... Almost 5 gallons of oil. Its taken some getting used to trying to shift this beast.



Jason

 

[HoleshotHolset]

Congratulations, Jason!



Awww, come on... it's only 2 GALLONS more than a 6BT!



I've only driven a transmission like that once... and I never got out of 1st gear. I reckon you'll be an old-pro in no time.



Matt

 

[bmoeller]

Originally posted by CumminsPuller

Almost 5 gallons of oil.

:-laf



An 855 takes 11 gallons.

 

[CumminsPuller]

Well I just got undere there and looked. It looks like a sensor of some sort at about the 10 o'clock position if your at the back of the transmission looking forward. It has two wires comeing off of it and about 6 inches down the wire they are connected with what I guess are called spade terminals. For easy connecting and unconnecting I presume. No connector. So I take it this is the speed sensor?



Jason

 

[bmoeller]

Yep. There should be a connector, instead of the spades. Must've been damaged during the swap, or prior to install. Or an idiot cut the wires, instead of looking for the connector.

 

[CumminsPuller]

Well I pulled it out yesterday and could not physically see anthing wrong with it. I stuck my finger in the hole and did not feel any sort of 'Tone Wheel'. Not that I know what one looks or feels like. But feeling around in there I did not feel anything abnormal or loose. I reinstalled it by bottoming it out then backed it off 3/4 of a turn. Started tightening the jam nut down and SNAP!!!!! ... ... S***, now what? Well I did not realize the sensor was plastic, couldn't tell, then again I really wasn't looking for that. Damn jam nut is metal. But I left the boke part threaded in there and took the truck for a drive to make sure nothing leaked out. I'll leave it there until I can get a new sensor. I guess I will solder the connections next time, unless someone has a better idea?



Jason



P. S.

Looks like this is an RTO-11609A transmission. And from what I can figure out it should hold about 27 pints/13. 5 quarts. Sound about right?

 

[bmoeller]

I'd see if you can get the connector for the harness end. Shouldn't be too much. Could go to a salvage yard and get one from a wrecked truck. Would simplify things later, if need be.

 

[CumminsPuller]

Does that fluid capacity sound correct?



Jason

 

[bmoeller]

It's been several years since I've changed the oil on a 8. 3. Sounds about right though.