I pull a steel 20ft gooseneck trailer with 3 1000lb horses to Barrel races for my daughter with my early 99 stock f350. While towing I always turn the overdrive off. I pulled a friend of ours this weekend to the barrel race and he wanted to know why I did not leave the overdrive on running down the interstate. He said he leaves his on when running down the interstate but I always thought this bad on your transmission. Is it or can I run in overdrive?

Also the on/off light on my gear shift has gone out how easy is it to replace?

 

Once your up to speed on the intersate you'll be fine going into OD. I turn it off if I'm pulling hills. I'll see if I can find some pics of the OD bulb for ya.

 

Thanks does the end just screw off or how do you get to the bulb?

 

You only need to turn the OD off if you truck is having hard time pulling it. If it is going in and out of OD then you are creating a lot of heat and that is when you should turn it off and save the tranny some work by not going back and forth.

 

i've always towed with OD on. the only time you have to be conserned is when the tranny starts searching for gears, in and out of OD alot thats what causes heat and kills the trans. like hucka1a said when coming to a hill you can turn it off. also might be good to invest in some gauges to moniter temps. pulling a load and being able to watch your trans or exhaust temps helps you determine problems before you have a problem.

 

When hauling horses i find it best just to leave od off... That way when you get to a hill and or need to accelerate you dont give the horses a jerk by having it in od and then turning it off... These trucks will run at 2500 rpm all day long.

 

I also tow with OD on.

 

The end of the shifter just slides off, but be careful, there are wires attached for the OD light! I don't know if it splits, I only know that I have to keep pushing mine back on.
I don't think I want to glue it either.

 

This is the only picture I could find of the OD light and button removed. I thought I had so more(better) pics. IIRC. Twist the end cap 1/4 turn counter clockwise and it will slide off.

 

Thanks for the help guys,

Also Hucka1a how hard was your 6637 conversion?
I went to the NAPA store in town and the guy said he had never heard of a 6637 filter.

 

Here ya go:
https://www.ford-trucks.com/forums/2...-my-truck.html