1991 crew with 454 and 4l80e shifting issue

[duramaxing]

any body had a shifting into overdrive issues on the 4l80e ? i have a 1991 crew v3500 4x4 4l80e when you start out it goes from 1st to 2nd very quick then shifts to drive normal and then wont shift into overdrive. if you try to shift manualy its shifts to 2nd on its own without moveing the shifter then when you shift to drive it tries to go into overdrive for just a moment then goes back to drive. if its going down the road at around 55 in drive and let off the gas its like it goes in nutrel thought it was the transmission needing replaced or rebuilt and i replaced it but its doing the same thing?

[ghettoluxury]

Sounds like a computer or speed sensor issue

[joe231]

Have you checked the plug on the side of the trans? Unplug it and look in the plug for transmission fluid. If there is fluid, clean both parts thoroughly with brake clean, plug it back in and try it.

Also have you checked the trouble codes? Those can be helpful in pointing you in the right direction.
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[DetroitDan]

change the speed sensors first. trans temp sender might be bad too, telling the trans its cold or hot when its not.

[duramaxing]

thanks for the help finally got a computer to work after one used and 3 refurbs running and shifting great thanks for the help.

[ghettoluxury]

No problem. That is the reason this forum is so great, there are plenty of knowledgeable people willing to help.

[joe231]

Glad to hear it!
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