97 Ford F250 LD 4x4 - problem

[MarksTLC]

Hello all,

I have a quick question I'm hoping someone can help me with. My Ford has an electronic selector for engaging the 4 wheel drive. Sometimes it works, sometimes not. The selector knob and relays check out. I don't get the feeling it is electrical. Does anyone know of a problem like this? Maybe vacuum related. When starting out cold, the 4x4 will stay engaged for maybe 5 minutes and suddenly disengages. After the truck is warmed up it won't go in at all, most of the time. For some reason sometimes it works fine.
Specs are as follows: 1997 Ford F250, light duty, 4x4, auto, 76K miles, short bed. I don't know what else to tell you.

Thanks for your time. This is an awesome site and a great group of people. Later, Mark :confused: :help: :drinkup:

[Tevi]

Sounds like vacuum leak.

[xcopterdoc]

Check the vacuum canister on the front diff. Being from the salt belt it may have rotted thru. Also on the backside of the transfer case is an electric motor that shifts the transfer case into 4 wheel drive. make sure that the truck is actually shifting in and out of 4wd. It may be an indicator light problem. Hard to diagnose one of these without seeing it.

[MarksTLC]

Thank you very much for the advice. I will look into all possibilities. I have sometime, but don't want to forget about it till next snow.

My sincerest thanks again, Mark

[xcopterdoc]

Nitelord.. PM me with your engine size and VIN# and I'll look and see if there are any TSB's on this problem.