No overdrive

HockHD · June 11, 2017

Hi fellas new guy here been trying to search this for a few weeks with little to no luck but i have an 07 2500hd classic with the 6.0L and a 4l80e i would assume. My issue is it seems to go through the gears just as it should but will not go into 4th gear. I am a little embarrassed to say i didnt even realize this until i was on the highway 70mph or so and I tried pressing the tow button on the gear shifter and the light would come on but no downshift like i would have thought just keeps riding about 2500rpm or so around 70mph. Fluid and temp seem normal. Hoping there is an actuator or solenoid gone bad. Going to AutoZone this evening and see if they can see any codes. Thanks for any advice

O_J_Simpson · June 11, 2017

Vatozone is not a good place to rebuild your transmission. You need a good transmission shop to fix it right.

Formulabruce · June 11, 2017

Hi fellas new guy here been trying to search this for a few weeks with little to no luck but i have an 07 2500hd classic with the 6.0L and a 4l80e i would assume. My issue is it seems to go through the gears just as it should but will not go into 4th gear. I am a little embarrassed to say i didnt even realize this until i was on the highway 70mph or so and I tried pressing the tow button on the gear shifter and the light would come on but no downshift like i would have thought just keeps riding about 2500rpm or so around 70mph. Fluid and temp seem normal. Hoping there is an actuator or solenoid gone bad. Going to AutoZone this evening and see if they can see any codes. Thanks for any advice

The "Tow" button ONLY disengages the "LOCK UP" solenoid. 2500 rpm at 70 mph is where your RPM should be at 70 ish with a 4.11 gear ratio in the rear. When working right, you cant even feel the lock up go in and out without a load. Its likely you have no problems at all.

HockHD · June 11, 2017

The "Tow" button ONLY disengages the "LOCK UP" solenoid. 2500 rpm at 70 mph is where your RPM should be at 70 ish with a 4.11 gear ratio in the rear. When working right, you cant even feel the lock up go in and out without a load. Its likely you have no problems at all.

HockHD · June 11, 2017

Thank you bruce I believe you are right, ever so slightly can you feel it go into overdrive. Goes to show how much i really dont drive this thing. Thanks a lot

brettsacto · February 20, 2020

On 6/11/2017 at 9:11 AM, Formulabruce said:

The "Tow" button ONLY disengages the "LOCK UP" solenoid. 2500 rpm at 70 mph is where your RPM should be at 70 ish with a 4.11 gear ratio in the rear. When working right, you cant even feel the lock up go in and out without a load. Its likely you have no problems at all.

Absolutely - thank you for this. I bought a project truck used - and of all the things I didn't consider - was the overdrive. I took it onto the freeway manually shifting through the gears with the tow setting turned on (trailer light activated on dash). 1, 2, 3, and into 4th. I pressed the button expecting it to go into full overdrive (technically 5th as my other trucks have) and it never did. I've been concerned that the overdrive was disconnected or malfunctioning and was about to start digging into the brake controller and tracing down the tcc connection. I expected the truck to rev a bit higher since it was a 3/4ton HD 4x4.

I was concerned that the thing was running all the way up at 2500rpm @ 70mph. I just thought this was way too high! I thought it had a 3.7x gear set in it, and I'm guessing that I was wrong. I need to decode the VIN - but at this point I suspect it's a 4.11

I am going to verify this with another source, but reading this gave me a warm fuzzy I haven't had for a month!

KUDOS and THANK YOU!!!