# RPM and Overdrive on F550



## sgoalie23 (Jun 20, 2004)

We picked up our "new" used 2001 F550 4x4, diesel, auto, today from the dealer. On the way home I noticed that the OFF light for the overdrive on the shifter does not light up. I am now trying to figure out if the overdrive is on, off or is not working. At 70mph the truck is registering 2800 RPM. I assume that the truck has a 4.11 or 4.88 rear end. Any thoughts on this or how I can figure out the problem. Right now, taking it back to the dealer is a little bit of a hike. (50 miles one way). Thanks.
Mark


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## Jay brown (Dec 26, 2005)

top speed on our truck is about 75-80 mph. it has a 5 something gears


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## Travel'n Trees (Jan 17, 2006)

throw a exhaust tempature gauge on it because at 68 mph it is running too hot and can burn up the turbo quick, you buy it and expect it to drive down the highway without burning up it's motor.


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## oldmankent (Mar 2, 2001)

sgoalie23 said:


> We picked up our "new" used 2001 F550 4x4, diesel, auto, today from the dealer. On the way home I noticed that the OFF light for the overdrive on the shifter does not light up. I am now trying to figure out if the overdrive is on, off or is not working. At 70mph the truck is registering 2800 RPM. I assume that the truck has a 4.11 or 4.88 rear end. Any thoughts on this or how I can figure out the problem. Right now, taking it back to the dealer is a little bit of a hike. (50 miles one way). Thanks.
> Mark


While your cruising at a say 60 mph down the highway under no load hit the button. That should make the tranny shift either up or down. Not sure about this, but I'd think it would work. Sure it isn't great for the tranny, but it should be able to handle it once or twice.


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## SLSNursery (Dec 21, 1999)

*At startup I am pretty sure OD is ON*

I think the default mode at startup is OD is on, so the truck will run through all of the available gears if you do nothing. If you start the truck, and press the button one time you would shut it off. Then drive the truck and get up to highway speed. With the OD off, unloaded the truck will drag when you let off the accelerator. If you tap the OD button at that point it will shift into OD and OD would be on again. If nothing happens you probably have some kind of electrical disconnect. Did you check the fuses by the way?


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## zapster (Feb 21, 2006)

yes the truck will be automatically in overdrive when you start it

you have to press the button on the shifter to get out of o.d.

another way to see if its in o.d. is to go about 60 or so ..
after it goes thru the gears and your crusing along leave the throttle pedal in the same position and just tap the brake pedal with your other foot
the truck will downshift to "drive" when you do that
watch the tach..it should jump up about 1k rpm
at least mine does  

99 7.3L F-350 duallie dump 4X4 9'fisher

...zap!


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## sgoalie23 (Jun 20, 2004)

Took it out on the highway this AM. Counted five gear shifts and pushed the OD button and nothing happened. So, the truck, by default is in OD mode and canceling the OD is not working. I checked all the fuses and they are fine. The dealer replaced the end cap on the gear selector and he may have some how disconnected something inside. I will call him Monday.


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## Fordistough (Feb 14, 2005)

I'm not too sure if that's true. I think if you press the button, and then startup again later it is still locking out overdrive.

-Thann


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## MickiRig1 (Dec 5, 2003)

Might check your fuses. There was a post on here about a truck blowing the fuse for the overdrive switch. ( he had bad wires )They may of popped the fuse replacing the end cap and never checked the function of the switch. Those end caps come off all the time but the light still works most times.


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## sgoalie23 (Jun 20, 2004)

*Update*

The dealer replaced the whole shifter arm with the OD mechanism included. He also said something about the signal to the transmission. Bottom line-problem resolved under warranty.
Mark


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