Originally Posted by trevorbg
hi from trev
i have a 4l60e behind a 350 lti motor in a 56 chev
i lost 1 2 4th gears after 100 mile drive
i drove home in 3rd
got up next day drove around for a while alls good till i was driving up my street then i lost 1 2 4 again and speedo
is this a gear box problem .
i checked connections to box seems ok
are you using the OEM wire harness and ECM (computer) ?
As suggested , the trans is going into the limp mode = 3rd gear only.
This is usually the result of a connection problem , loss of voltage and computer feed to the trans.
Check connections (all of them) and the ground wires too! loose pins in the harness connector , poor grounds or no ground hooked up.
Engine properly grounded to the chassis, battery grounds to the engine , chassis.