2009 Silverado 1500 2wd *4L60e Tranny Jumping into reverse

[ENolan16]

Working on transmission, truck shifts in all gears normal, except the reverse you have to give it gas to get into reverse. You can hear it shift into reverse but will not move until giving it gas. Asked owner when last time transmission has been serviced and he is unsure, but it is noticable it's been in the last 6 months to a year being it has brand new, fine smelling fluid. 

[carnau]

Do you have any codes in the vehicle? Is it only after sitting a while that it does this or does it do it all the time no matter how far it is driven? the codes will really help me because i think it is one of a few issues.

 

One - low fluid level ( the easiest to check, Make sure to check while running. )

Two - internal suction filter could be cracked. ( have to remove the pan )

Three - a stuck lube regulator valve in the pump cover. #13 in the picture below.

 

If it is 13 being stuck, a transmission service with a cleaner could help it. Worth a shot for 25$

Here is a flush and additive I would recommend. The number 1 cause of transmission failure is Heat. This is supposed to help cool it chemically.

I would flush it, replace the filter and gasket, add the protectant. I will link the one with the better reusable gasket below.

 

Filter kit - https://amzn.to/2GFyq8q 

Flush and Protectant - https://amzn.to/2BAgdph

 

 

 

[carkhz316]

A relatively common issue with the 4l60 is a leaking/ worn boost valve. This will cause a loss of or slipping reverse, and low line pressure rise. I often replace them preemptively in ones I've rebuilt. It's an inexpensive part ($20-30) and can be replaced with just a pan drop. I recommend the Sonnax kit.

 

carnau: Unfortunately, that's not a 4l60e pump, but below is. The boost valve is the smaller black one  on the left. The larger open hole just to the right of the middle is where the trans filter is stuck into.

[ENolan16]

Thank you. I also noticed, finally that I've gotten under the truck that the fly wheel is exposed due to a round plate being missing on the tranny! Curiously, is it possible something flung up inside that would have caused the reverse issue? 

[carkhz316]

No, that's merely a inspection cover/ access. You would have heard terrible noises if anything got up in there. The only real purpose is to inspect for leaks from the front seal, and flywheel inspection. 

[ENolan16]

Okay. Luckily no leaks anywhere. No over heating. It's just that strain to get into reverse even when I can hear it engage whether its fully engaging or not. 

[ENolan16]

Can a faulty shift solenoid cause the same issue?

[carkhz316]

No, because even with complete loss of power to the transmission/ aka "limp mode", it will still shift into reverse as it's a hydraulically controlled shift.

[ENolan16]

What size is the torx to take the shift cable bracket off? 

[carkhz316]

I believe they're T40, but if you're just dropping the pan, you can gently pry the bracket to the side to get the pan down without bending the bracket. It has enough flex to squeeze the pan out beside it.

[ENolan16]

How do I remove the sensor clip in front of the boost valve?? 

[carkhz316]

So I didn't think about it until now' that your truck has the input speed sensor. Ugggh. I think that's almost impossible to remove with the trans still in the truck.

[carnau]

On 2/14/2019 at 9:33 AM, carkhz316 said:

A relatively common issue with the 4l60 is a leaking/ worn boost valve. This will cause a loss of or slipping reverse, and low line pressure rise. I often replace them preemptively in ones I've rebuilt. It's an inexpensive part ($20-30) and can be replaced with just a pan drop. I recommend the Sonnax kit.

 

carnau: Unfortunately, that's not a 4l60e pump, but below is. The boost valve is the smaller black one  on the left. The larger open hole just to the right of the middle is where the trans filter is stuck into.

Ha, Yeah. I just happened to have a picture of the Allison one. Still the same spot as the 4l60... Just a few more parts.

 

[carkhz316]

Ah gotcha. Ya, sounds it like OP might be have some trouble anyway, as I ignored the fact that his has a input speed sensor (2007+ had this), which pretty much requires Trans R&R to get the boost valve out.