TH-350 stuck in 1st gear?

Question

My old man has a mid-late 80s chevy van that went about 300 miles down the road and then got stuck in 1st gear. I dont know if this particular model of transmission is the "lock-up converter" model or not, but the "shop" down in this crappy little town told him that they thought the tourque converter was stuck in lock up and I told him if that were the case, I thought it would be stuck in 3rd cause that is the direct drive right? Anyhoo, we went and got it rescued and I was just looking for some insight into one of these stuck in 1st gear. I told him to check the modulator and just to be sure, he went to Napa and replaced it, also I had him check the detent cable before I came down, but everything seemed fine.

Answer 1

No it isn't the shift modulator or the converter. It is the shift governor that is stuck. If it was the shift modulator the transmission would shift, however the shift scheduling would be very late.

The governor has probably stuck or has the teeth worn off it. In any case it needs to be replaced. If you remove it and it looks fine to you, try cleaning it very well with some brake cleaner

Answer 2

maybe the vacuum modulator is bad.