What trans is this?
 

I have a 90 silverado k1500 with a 350 in it. Standard cab, short stepside bed. Im trying to figure out what transmission i have in it. Looks like im going to have to rebuild it pretty soon, the truck shudders and looses power in overdrive, let off the gas and get back in it and its fine.

The transmission pan is about 12x14 inch with two little bump outs at the back of the pan

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lllllllllllllllllllllll
lllllllllllllllllllllll
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l__--__-- l

looks something like that.

From what I have found i think its a 700R4. Am I right?
Also, anyone got any idea whats actually going bad?

If it's the factory transmission than yes it is a 700R4.

its not the original transmission, its a rebuilt replacement that was put in years ago. I dont think the average shop would have changed transmission types though.

Hope this helps

Attachment 2375

If it is overdrive than it is a 700R4.