I recently purchased a 1976 Ford F150 4x4 that will not engage 4H. I have heard of issues similar to mine for this model and year and was curious if this was a know problem or not.
This is a 46 year old vehicle. At this age there are no “known” problems. Everything in this vehicle could fail at any time.
If you are going to fix this yourself, start inspecting the truck… 4WD lever linkage first, transfer case next. If you think it is the t-case, disconnect the linkage and move the lever by hand. If it goes into 4wd, it is a linkage problem. If it doesn’t, it is a t-case problem. Post back and we can try and help.
If you can’t do your own work, good luck finding a shop that can work on something this old.