I have a Case 1150G; right pedal will not steer in high range.
If you answer all these questions I may be able to help.... Does the right track, neutralize & lock up when the brakes are applied? Or won't the left track push the machine to the right? When the machine is at operating temp, at an idle, is there any hesitation when you select forward low or high? Does it take the same time to engage low as it does high? Does fwd or reverse make any difference? Do both tracks engage at the same time? Can you check the transmission pressure while doing these tests? You will need to install a test gauge to the control valve. That will also help.
Doe's it steer with the lever and not with the pedal? If this is case I would think the right brake is getting weak.
Did you get the steering issue figured out?
Anybody happen to know where I might find a manual to rebuild the transmission of a 1150? Not the 1150G manual, the transmission manual.
Might try Ebay or Case CE dealer may print off the trans section for you.