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Late shift in Suburban transmission

I have a '89 2500 4x4 Suburban. It’s a heavy duty transmission: 3 forward speeds, no overdrive. Rebuilt about 5 years ago, 30K miles since.

A couple of months ago, I noticed it’s shifting late. Won’t shift into 2nd till about 25mph, and won’t shift into 3rd until about 50.

I’ve check the fluid level and it looks good.

Any ideas?

Check the TV cable attached to the throttle. It is one of the things that controls the shift points of the transmission. If it is broken, it is easy to replace. It may just be out of adjustment.

Thanks, BustedKnuckles! Sounds good … and cheap. My uncle mentioned the same thing. I’ll check it today and let you know …

Here’s the poop …

I have a 400 Turbo transmission … no TV cable. Instead, I have a “vacuum modulator”. The cover/something or other was loose, and the loss of vacuum was causing it to shift late. Shifting perfectly now.

I was looking for a new mechanic, had a bad spot on the starter, and tried the closest one recommended by this website - Tread Quarters. Only one review, but it was good (like lots of dates I had in college). It was cold and wet here so I didn’t want to go napping under my Suburban.

Anyway, to make make a long story short, shifting problem fixed - no cost!

Yeay Tread Quarters!