[Black GMC]

I am having some problems with my 700r4, I went to drive my truck a few days ago and noticed that it was not shifting out of first gear until the truck was warmed up, after that it shifts like normal. Can anyone tell me what they think the problem is?

 

[offroadohio]

Mine is doing the same thing. Still no for sure answer ive found.

 

[Black GMC]

I don't know what the cause of the problem is , but I looked under my truck and noticed that I have a pretty bad atf leak is looks like its coming from the front pump, so I am just going to try to rebuild it myself, any advice on what mods I should made to make it stronger?