trans shift

[77 cc lb]

I recently bought an 88 R20 suburban with a 454/th400 trans. The trans. was rebuilt a couple years ago. It doesn't want to go past 2nd gear, was wondering if the modulator could be bad or something else. I added a qt of fluid because it was low and still no difference. Any ideas would be appreciated.

[slammed79]

Can you manually get it in to third? If not it could be gone.

[Lt.Del]

you sure your vacuum line (to modulator) is still hooked up to the intake vacuum behind the TBI?  I guess the '88 TBI th400's are that way.
Passing gear stuck in passing mode?

[77 cc lb]

Thanks Lt.DeL and slammed I will check those out. I am going to try and get a hold of prev. owner to see who did the repair and a couple other things. Thanks guys