Jime

Got a 4l80e tune file loaded in Hptuners, all gears seem to be ok in auto mode and manual except for 1st gear, when the car starts to move forward its like somebody is putting the brakes on. It starts off ok at low throttle but if I give it a little more gas it will brake to a stop. If I activate the brake in 1st it stays put at any amount of throttle as it should and goes when released but then it starts braking again when I start moving. Any ideas?

70ls1chevelle

iTrader: (119)

I have a built 4l80E with Jakes transbrake the one you can use in any gear.My car will start out in second gear from a stop( In drive on the selector) the car moves 15-20ft and will shift straight to third and lock the converter, to the point the engine will stall,feels very violent as if it were going to reverse.

I hooked the scanner to the car and commanded the car to stay in first and second with good results but as soon as I let the tune control the car it will act up, when the car shifts it does not see the mph to shift, seems to shift on time.Is this similar to yours ?

Jime

I played with it a bit more this morning and it works ok except in first. If I start in any other gear it starts in first and shifts up as per normal. I tried to command first but it doesn't stay just shifts up. I can hear the noids clicking when car is off and gears show in scanner as it shifts, its just this manual low that won't work.

Monzsta

I've got a very similar problem with my 4l60e. I suspect the range switch might be the issue. On the trucks it's on the transmission shifter shaft but in our cars it's in the shifter itself.

I'm pulling the trans this weekend for some maintenance (torque converter swap, replace all the wiring, solenoids and pressure switch plate, and adjust the servo) so I'm going to take a hard look at the range switch and shift cable adjustment.