Those with a manual overdrive switch I have a ?

[nitrofumes]

Hello everyone!

I bought a clean '92 CC 4x4 auto D250 this weekend. The previous owner has installed a manual overdrive switch in the truck.

My question is in non-towing situations how do you guy control the trans going into overdrive? Do you just leave the switch engaged and just let the transmission do it's thing or do you leave it disengaged until around 50-50 mph?

I ask this because on my truck with the switch engaged it shifts into overdrive around 30-35 mph which just seems too early to me...however with the massive torque of the Cummins the truck really doesn't care – it just motors on.

Thanks in advance!

[dazedandconfused]

Mine is on a floor switch and its either on or off, it won't hit OD unless i hit the switch.

[nitrofumes]

That is the way mine is rigged up as well.

I guess my question really is should I leave the switch 'on' all the time (non-towing) or only switch it 'on' when I reach cruising speeds.

[dazedandconfused]

I only hit mine when its up to speed and rpms are up in 3rd.

[nitrofumes]

Awesome. That's exactly what I needed to know. It is a dumb question but I wanted to know for sure.

[Sutter1stgen]

I have been distracted and left mine in the on position. Went to go take of, and there is a huge jump between the 2-3 shift. It freaked me out. Now it's not really a big deal and I flip it down real quick.