93 IDI won't shift into OD?

[kuntryquesttsi]

trans is less than a year old. Usually I drive about a mile in the cold and it will shift into OD. I don't beat on the truck I just drive it, don't tow anything either.
It took nearly 10 miles before I hit OD. Witch was when I came into a 45 zone
Any ideas?

[63mercury]

it might not be an overdrive problem,it might be the lock-up torque converter, when cold mine(e4od) will stay unlocked for almost 5mi, once warmed up it shifts just fine, to check it use the manual OD button to disengage and engage when you are traveling faster than 36mph as this is where OD will kick in.