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Posted (edited)

IMG_5497.thumb.jpeg.3390ec775066890af1ed7e2e888ea36e.jpegQuick introduction: I have a 2019 Chevy Silverado LT. The truck has Camburg UCA’s., King IBP 3.0 coil over front shocks, King IBP 3.0 rear shocks. Deaver leafs springs, 35” BFG, amp electric steps, and quite a few other additions to the truck.

 

I wanted to post about my recent experience with re-gearing my truck. Hopefully this will help somebody somewhere because the information that I tried to find is extremely limited. 
 

My gear ratio was 3.23 and I went to 4.56. The company that installed the gears originally put a Hyper-Tech in-line speedometer and gear calibrator on the truck. It worked fantastic driving around town, but once I broke the gears in, I started driving and on the freeway. While on the freeway doing 79 mph I got a notification on the dash that stated truck is governed at 92 miles an hour. Then the throttle was dead (governed)  Keep in mind my speedometer was dead on with GPS. I spoke with Hyper-Tech about this and they stated it’s potentially too big of a gear change. They only know of the in-line calibration working up to 4.10 gears. (That is not confirmed).
Something in the rear end wasn’t talking with the computer in the front end so I bought an edge pulsar LT in-line calibrator thinking that that would work better. I ran into the exact same problem except the governor was now set at 112 MPH (which is the stock setting on that truck). But at 85 miles an hour my driveshaft felt like it was going to detonate. Basically the rear end was turning the driveshaft RPMs as if it was doing 112 mph. 
I finally found a company that re-geared a 2019 Chevy Silverado with 4.56 gears and they ran into the exact same issue. The way they ended up fixing it was the truck had to be tuned not performance tuned just tuned so it accepts the new gears.

 

I’ve been dealing with this problem for about a month now and I finally caught a break two days ago and received that information and had the truck tuned and it drives absolutely perfect shift. Perfect. Everything is like stock. 
 

Hopefully this helps somebody looking for some information. I don’t know if this applies to 2022.5 and up I just know specifically it applies to 2019 through 2022 pre-refresh. 

Edited by Luckyfd1
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Posted

Yes, I wasn’t very specific. lol. ECM/TCM. He was able to unlock both from his laptop. Which I thought was odd because all the ECM and TCM tunes you buy online you have to get to those units to unlock them, but I guess there’s other ways. IDK? 

Posted
4 minutes ago, Luckyfd1 said:

Yes, I wasn’t very specific. lol. ECM/TCM. He was able to unlock both from his laptop. Which I thought was odd because all the ECM and TCM tunes you buy online you have to get to those units to unlock them, but I guess there’s other ways. IDK? 

Yeah, I had always heard that you have to "unlock" the ECM and TCM to program them, there are units that can be bought for that now but I think they only allow there own tunes.

It would be GREAT if you could find out what program etc he was using.

Glad you finally got it figured out, how is the performance now and any info on cruise RPM at like 75mph?

Is gas mileage still good?

Posted

Thanks! I will ask the guy and post it on here. So I didn’t have him delete anything or change anything except for the tire size and the gear modification. The truck is getting a Whipple, long tube, and DOD delete kit, larger cam. So we’re gonna have to tune the truck after these parts are installed. But as of right now, I can’t tell you how amazing the gear change is. For those who have changed gears before sometimes it feels like it didn’t change anything at all… I still have really good RPMs on the freeway and it just wants to pull the tires off on the surface streets.

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Posted (edited)

Come on vacation leave on probation that’s the Vegas motto

 

besides bad decisions, make better stories! 

Edited by Luckyfd1
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Posted (edited)

That’s a good deal. 1/2 off almost! 
 

my house is kinda like the federal government. I get a certain amount to spend every year, if I don’t spend it, I won’t get as much the next year. I’m at the end of the fiscal year so I’m dumping money! 

Edited by Luckyfd1
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Posted

Appreciate the info Luckyfd1, I too have a 2019 Silverado 5.3l, but it's a RST, I Have Cognito upper control arms with 3.5 Rough Country coilovers and almost 35" in tires but not quite. I've been looking for some one to tune or calibrate the speedometer odometer to match tire size for better shift points. I've also am considering the hyper tech speedometer odometer calibration programmers but now that you mentioned the freeway issues, I'm glad I haven't pulled the trigger. Would you be willing to give me some info as to where you had the calibration done. And the cost. I'm in the L.A area 562 area code. Thanks

 

Posted
11 hours ago, Luckyfd1 said:

Come on vacation leave on probation that’s the Vegas motto

 

besides bad decisions, make better stories! 

Except in Utah, where the Vegas tag line is "What happens in Vegas stays in Vegas,.... except STDs.  That ****** will haunt you for life."

  • Haha 1
Posted
11 hours ago, Luckyfd1 said:

That’s a good deal. 1/2 off almost! 
 

my house is kinda like the federal government. I get a certain amount to spend every year, if I don’t spend it, I won’t get as much the next year. I’m at the end of the fiscal year so I’m dumping money! 

That's not the federal government fiscal policy.  That's a government agency policy.  The federal government policy is to spend, spend, spend, even when they'd don't have the money. 

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Posted
9 hours ago, Albert Palos said:

Appreciate the info Luckyfd1, I too have a 2019 Silverado 5.3l, but it's a RST, I Have Cognito upper control arms with 3.5 Rough Country coilovers and almost 35" in tires but not quite. I've been looking for some one to tune or calibrate the speedometer odometer to match tire size for better shift points. I've also am considering the hyper tech speedometer odometer calibration programmers but now that you mentioned the freeway issues, I'm glad I haven't pulled the trigger. Would you be willing to give me some info as to where you had the calibration done. And the cost. I'm in the L.A area 562 area code. Thanks

 

Those tires would be called "Metric 35s."  Since you like Rough Country, look into their catalog.  They have a speedo calibration device.  Plug it into your computer, run the install wizard, tell it your OE tire size and then your new tire size, and it'll write the code.  You then take it to your truck, remove 1 plug under the drivers side dash, plug the RC wire harness into that port, insert plug you just remove into the RC harness, and then tuck the rest of the wires away.  The entire process should take you less than an hour.  I've been running the RC speedometer calibration device for over 2 years.  No problems, yet (knock on wood).

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