Help

[Josh20315]

New crate motor 5.7 vortec got put in my 96 cc long bed srw it has a 4l80e at 70mph I’m at 2800 rpm is this normal?? Idk gear ratio

 

[Komet]

Gear ratio is the thing you need to know to determine whether that's normal.

 

[Josh20315]

It’s a c3500 so it’s probably 4.10

 

[Josh20315]

It’s a 14 bolt rear

 

[Sean Buick 76]

Well does it shift 3 times or only 2? What tire size are you running? Did you use a GPS to confirm your speed is correct?

With a 31” tall tire and a 3.73 gear it would be 2800 rpm in 3rd gear. Are you sure it’s going into overdrive and is the lockup converter engaging and lowering the rpm 200 rpm?

 

[Josh20315]

Well does it shift 3 times or only 2? What tire size are you running? Did you use a GPS to confirm your speed is correct?

With a 31” tall tire and a 3.73 gear it would be 2800 rpm in 3rd gear. Are you sure it’s going into overdrive and is the lockup converter engaging and lowering the rpm 200 rpm?

Idk man wish I could just let sum1 like u drive it

 

[Josh20315]

shifts into second at 20 into 3rd around 40 and I think into 4th around 50 or maybe that’s the overdrive just dropping it 200

 

[Josh20315]

Trucks on 245/75r16 stock rims

 

[Josh20315]

It’s a 4l80e

 

[Keeper]

Look at the RPO codes in the glove compartment. It will have either a GT4 (3.73) or a GT5 (4.10) code.