1994 gmc hd overdrive ?

[doych64]

I was wondering if overdrive on this truck is designed for all the time use or just highway . My trucks seems to shift into overdrive at 45-50 and lugs . If I am on the highway at 55and over no lugging at all .

[Marty Lau]

What year is your truck model we assume you have Auto tranny, what is your axel ratio and is this while towing? :confused:

[doych64]

My truck is a 1994 gmc hd . Dual wheel utility body . Not towing anything and not really loaded either .I really don't know the gear ratio what ever stock is .

[dslpwr]

Most people tow in overdrive.