HELP!! TH350 not shifting into 3rd when in 4 wheel drive ???

[Invictus]

I need some help trouble shooting.

I have a 1976 Blazer, 400ci w/ TH350 & NP205 Transfer Case.

When in 2-wheel driving the tranny shifts just fine through all of the gears. I can drive 70+ on the freeway without a problem.

When I shift into 4 wheel drive, the transmission wont shift out of 2nd. I've tried manually shifting and it still does not go into 3rd.

What could cause this? I've read that overfilling a tranny can prevent it from shifting into 3rd. Could that be my issue? I assumed it was not since it shifts just fine in 2 wheel drive.

Thanks in advance for any help.

Robert

 

[Invictus]

Well I figured it out. My transfer case isn't working in 4hi and is working in 4lo. I've been in 4lo the whole time.

Anyhow, I'm a dumbass. Thanks for all the replies!