Shifting very late

[Patrick1997]

I have a 1997 gmc 2500 with an exhaust and cai. I shift around 5k rpms and 52 mph, i’ve been told i should rev faster and shift around 35 mph. Unsure of my gear ratio but i’m guessing its stock. Just wondering what the problem could be.

 

[PlayingWithTBI]

I shift around 5k rpms and 52 mph

Hmmm - sounds like you're starting out in 2nd gear.

 

[evilunclegrimace]

Possible bad TPS. You need to check for codes.

 

[Patrick1997]

Possible bad TPS. You need to check for codes.

No codes and i put in a new tps a few hundred miles ago.

 

[Patrick1997]

Hmmm - sounds like you're starting out in 2nd gear.

And why would that be i’m just in drive stopped and then flooring it.

 

[PlayingWithTBI]

And why would that be i’m just in drive stopped and then flooring it.

It just doesn't sound right that you can be doing 52MPH in 1st gear unless you have pretty tall tires?

 

[evilunclegrimace]

Try manually shifting into first gear and see if it accelerates quicker

 

[L31MaxExpress]

double

 

[L31MaxExpress]

Completely normal for a 4L80E truck with 3.73s.

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[df2x4]

I was thinking more like 3.42s but yeah, that sounds about right for a 4L80E. They have a really long first gear. My '97 C1500 with 3.42s shifts into second right around there at wide open throttle.

EDIT - According to the ChevelleStuff gear calculator a 4L80E truck with 3.42s and an 80E will hit 52MPH in first at 5133RPM, assuming 235/75/R15 tires. 3.73s would put you at 5599RPM at the same wheel speed.

https://chevellestuff.net/tools/rpm_calculator.htm