No 1st or 4th after warming up

[Smokey364]

Like the title says after my truck warms up on the morning drive to work, I lose 1st and 4th gears at the first red light. I also have to manual downshift and it will only go down to 2nd. It will however start in 1st but slams hard when shifting to 2nd. I’ve replaced shift solenoids “A” and “B” both and replaced transmission fluid as well but that’s the extent of my fiddling with it without help. Any help would be greatly appreciated, this thing has had uncommon weird problems for the past 3 years I’ve had it but this is the worst so far

 

[zora]

Like the title says after my truck warms up on the morning drive to work, I lose 1st and 4th gears at the first red light. I also have to manual downshift and it will only go down to 2nd. It will however start in 1st but slams hard when shifting to 2nd. I’ve replaced shift solenoids “A” and “B” both and replaced transmission fluid as well but that’s the extent of my fiddling with it without help. Any help would be greatly appreciated, this thing has had uncommon weird problems for the past 3 years I’ve had it but this is the worst so far

You need to have the transmission scanned for codes.

 

[Smokey364]

You need to have the transmission scanned for codes.

I’ve used a cheap obd-2 and it read “shift timing solenoid “A”” but it’s still there after replacing both solenoids

 

[zora]

I’ve used a cheap obd-2 and it read “shift timing solenoid “A”” but it’s still there after replacing both solenoids

What's the actual code?

 

[Smokey364]

What's the actual code?

It reads P0785

 

[zora]

It reads P0785

That's the only code, no other P078x codes?

 

[Smokey364]

That's the only code, no other P078x codes?

Not at the moment, I just took a longer drive, about 25 minutes, to see how it felt and what would happen. It felt fine until I stopped at the next town to turn around and it slammed into gear and wouldn’t shift high again.