71 FJ40 transfer case or rear end

[villen]

I hope I am nearing the end of the rebuild of 71 FJ40, motor has been rebuilt (1F) clutch was just replaced. Finally to the point where I drove it around the block. It will only do 25-30 mph. After soooo many surprises on the project felt like I was on the home stretch. The motor sounds like it is running good, the clutch feels good starts to grab just off the floor. I left about 1/4 inch of gap between throughout bearing and clutch fingers. I drove it around the block with only the rear drive shaft connected. Transfer case shifter is left and all the way forward. Tach is not working but at 25 on speedo I would guess it is about 3000 rpms. It goes through the gears fine, shifts good.

I can only assume the issue is in the transfer case or rear differential. Is there anyway to determine where to look next?

Thank you all for your help
Steve

 

[brian]

in top gear you feel 25mph is it?
sounds like its in low range

 

[JohnnyC]

Can you confirm that the shifter is actually moving under the truck and going to high range watching linkage shift?