Grumpy Bears 2015 Silverado 2WD

KARNUT · March 4, 2019

Just started to look into doing some pumpkin smashing. I've wanted to install an Eaton Truetrac. Thing is to do this right I will need to replace the ring and pinion as well. If I'm going to do that then it seems fitting to fiddle with the gearing. Yes, lower and yes that will give back some efficiency. I have some to spare. So...what would I like to accomplish? What are my patterns. What are my expectations? What is Peppers future?

Not much chance I will decide on a whole new driving style and my favorite speed is 55 mph and my favorite roads are the back roads. Factory converter has a stall of a tested 1520 rpm. That has to figure into it. I know spinning the motor faster, even a few hundred rpm will increase heat. That has to figure into it as well. She is getting new shoes sooner than later. There's that.

New cover? Dutchman or Mosser axles? Steel driveshaft? Trans tune? Where will this end? Will it even start?

Stock tire and a 3.90 gear locks up the converter right around 55 mph. So does a 3.73 and a 245 section 70R-17. In both sizes I can source tires 3 to 5 pounds each lighter. Both of those lower converter clutch wear and reduce slip heat. And both would provide a nice boost in acceleration. (I'm old, not dead! ) 3.42 would keep the AFM lit more and against higher loads of wind and grade with as little as a 50 rpm increase.

I could also leave it as is and put my efforts towards the interior. Oh what to do....

I’ve never knock peoples taste in mods, I’ve covered the canvas. I think you’re truck would benefit in a tire wheel combo change. The wheel tire size would depend on the ride quality your seeking. I would be more tire less rim. I’m performance minded so the more gear the better. The gas mileage wouldn’t suffer that bad.

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diyer2 · March 4, 2019

I wasn't knocking Grumpy Bear.

I said Good Luck.

Just saying I'm glad I don't have the bug.

Grumpy Bear · March 4, 2019

1 hour ago, diyer2 said:

I wasn't knocking Grumpy Bear.

I said Good Luck.

Just saying I'm glad I don't have the bug.

Didn't sound like a knock to me. Sounded like sage advice and happy to hear your thoughts always.

Proverbs 15:22 (NIV) Plans fail for lack of counsel, but with many advisers they succeed.

1 hour ago, KARNUT said:

I’ve never knock peoples taste in mods, I’ve covered the canvas. I think you’re truck would benefit in a tire wheel combo change. The wheel tire size would depend on the ride quality your seeking. I would be more tire less rim. I’m performance minded so the more gear the better. The gas mileage wouldn’t suffer that bad.

Good thoughts all. None of this is cheap so I need to research this more. Working with a fixed budget. DIYER2's plan is cheapest and likely safest.

Luke 14:28-30 "Suppose one of you wants to build a tower. Won't you first sit down and estimate the cost to see if you have enough money to complete it? For if you lay the foundation and are not able to finish it, everyone who sees it will ridicule you, saying, 'This person began to build and wasn't able to finish.'

Here's a question. Last time I did something like this Richmond Gear was top of the shelf. Seems there is a shift to Yukon by several vendors. Why? Did Richmond go down hill? Did Yukon make some major break through?

KARNUT · March 4, 2019

I wasn't knocking Grumpy Bear.
I said Good Luck.
Just saying I'm glad I don't have the bug.

[emoji4]

I wasn’t implying that. It was a disclaimer. Some people love the steel wheel look. I would with baby moons and reverse. Showing my age. Keystones and Cragar wheels were up there too.

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KARNUT · March 4, 2019

Good thoughts all. None of this is cheap so I need to research this more. Working with a fixed budget. DIYER2's plan is cheapest and likely safest. [emoji4]

Luke 14:28-30 "Suppose one of you wants to build a tower. Won't you first sit down and estimate the cost to see if you have enough money to complete it? For if you lay the foundation and are not able to finish it, everyone who sees it will ridicule you, saying, 'This person began to build and wasn't able to finish.'

Here's a question. Last time I did something like this Richmond Gear was top of the shelf. Seems there is a shift to Yukon by several vendors. Why? Did Richmond go down hill? Did Yukon make some major break through?

It depends on what you’re goals are. I had a ten bolt in my 74 impala with a 700R4 transmission and a built 454 and a 373 gear. My wife’s daily back then. If I was going to drag it every weekend, Ford 9 inch or a 12 bolt. Probably the Ford 9 inch easier to change the gears. You could probably put the cheapest in and never have a worry.

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Grumpy Bear · March 4, 2019

Goals. Main one is the Eaton Truetrac. That's more of a want than a need. I mean it never goes off road and never will with my name on the title. She's never been driven in the snow, ever. Only once have I ever spun a tire on dry pavement. Curious if it would and yes she will. Wet weather. I get caught in that sometimes. I'd like to start touring this summer and I love the Rockies. Your drive the peaks long enough and snow will find you. Went to sleep on night in late June in Yellowstone. It was dry and 70F. Woke up to 3 feet of fresh powder and 25 F. I was on my Harley.

Thing is with 86K on the clock a new ring and pinion is a must. The ratio is the optional part.

swathdiver · March 5, 2019

On 3/4/2019 at 12:02 AM, Grumpy Bear said:

Just started to look into doing some pumpkin smashing. I've wanted to install an Eaton Truetrac. Thing is to do this right I will need to replace the ring and pinion as well. If I'm going to do that then it seems fitting to fiddle with the gearing. Yes, lower and yes that will give back some efficiency. I have some to spare. So...what would I like to accomplish? What are my patterns. What are my expectations? What is Peppers future?

Not much chance I will decide on a whole new driving style and my favorite speed is 55 mph and my favorite roads are the back roads. Factory converter has a stall of a tested 1520 rpm. That has to figure into it. I know spinning the motor faster, even a few hundred rpm will increase heat. That has to figure into it as well. She is getting new shoes sooner than later. There's that.

New cover? Dutchman or Mosser axles? Steel driveshaft? Trans tune? Where will this end? Will it even start?

Stock tire and a 3.90 gear locks up the converter right around 55 mph. So does a 3.73 and a 245 section 70R-17. In both sizes I can source tires 3 to 5 pounds each lighter. Both of those lower converter clutch wear and reduce slip heat. And both would provide a nice boost in acceleration. (I'm old, not dead! ) 3.42 would keep the AFM lit more and against higher loads of wind and grade with as little as a 50 rpm increase.

I could also leave it as is and put my efforts towards the interior. Oh what to do....

18 hours ago, Grumpy Bear said:

Goals. Main one is the Eaton Truetrac. That's more of a want than a need. I mean it never goes off road and never will with my name on the title. She's never been driven in the snow, ever. Only once have I ever spun a tire on dry pavement. Curious if it would and yes she will. Wet weather. I get caught in that sometimes. I'd like to start touring this summer and I love the Rockies. Your drive the peaks long enough and snow will find you. Went to sleep on night in late June in Yellowstone. It was dry and 70F. Woke up to 3 feet of fresh powder and 25 F. I was on my Harley.

Thing is with 86K on the clock a new ring and pinion is a must. The ratio is the optional part.

After reading the first post, my first thought was that the Truetrac was a want and not needed. Any gear change has to offer increased fuel efficiency for that is the game. Same with tires. I do not remember, does Pepper have a 3.23 or 3.08 gear? Judging from the rest of the second post, I think she has the former.

Those tires have served you well, beyond any of our expectations, going to run them again? Same size? What is the size?

Grumpy Bear · March 5, 2019

51 minutes ago, swathdiver said:

After reading the first post, my first thought was that the Truetrac was a want and not needed. Any gear change has to offer increased fuel efficiency for that is the game. Same with tires. I do not remember, does Pepper have a 3.23 or 3.08 gear? Judging from the rest of the second post, I think she has the former.

Those tires have served you well, beyond any of our expectations, going to run them again? Same size? What is the size?

Good old 30 spline 10 bolt open fitted with 3.23:1 the OEM GM gears. As generic as it gets. Stan has had them work nicely behind 454 BBS's driven sanely. As a heavy equipment operator his "sane" might be a bit more liberal than average.

I am not unhappy with the Bridgestone Dueler HT D684 II at all. They get allot of bad press from the consumer review set but they have been very good to me. They are 255/70-17. This is the smallest diameter rim that will fit with the Bell 2" drop Knuckles she is wearing. The General HTS is also OEM fitment and 4 lbs. a tire lighter. The same weight at the Bridgestone in the 245/70-17, a size fitted to the previous generation. That size also opens up Pirelli and Continental. We have Continentals and like them. The Pirelli was a Consumer Reports best pick a few years ago. Fuel mileage was one of Pirelli's standout points in that review. We have Michelins on several vehicles here and while they are a great tire...they know it as it reflects in price. For my usage they offer nothing extra.

On a warm windless summer day 30+ mpg is a given and that number is insane from something with this much frontal area. Much of that number has come from refinements that have reduced internal friction to the point the AFM is literally its default mode. It comes out when timed out, against moderate to stiff winds and hills over 3% in grade and longer than 1,000 feet. It turns very slow now at my preferred 55 mph. Mid 1300 rpm range. Rarely tips back to 5th gear and is overall well behaved.

A 3.08 gear would slow the motor to under 1300 rpm. Take away the leverage that allows her to stay in AFM.

A 3.23 gear is a known.

A 3.42 gear adds a bit over 50 rpm to the cruse rpm, increases leverage and may help keep AFM active longer. Maybe.

A 3.73 gear spins the motor fast enough to cover the stall speed of the converter taking load off the converter clutch but adds 12% to the operating speed and increases fluid temperatures. It's a pretty steep first gear.

A 4.11 gear is like running in M5 and I've done this extended at times. I know this gear will reduce mileage. It will also stay in AFM up a pretty steep hill. I could swap the motor for a Briggs & Stratton with this gear.

Just some early thoughts based on everyone's input and some rough draft research.

KARNUT · March 5, 2019

Good old 30 spline 10 bolt open fitted with 3.23:1 the OEM GM gears. As generic as it gets. Stan has had them work nicely behind 454 BBS's driven sanely. As a heavy equipment operator his "sane" might be a bit more liberal than average.

I am not unhappy with the Bridgestone Dueler HT D684 II at all. They get allot of bad press from the consumer review set but they have been very good to me. They are 255/70-17. This is the smallest diameter rim that will fit with the Bell 2" drop Knuckles she is wearing. The General HTS is also OEM fitment and 4 lbs. a tire lighter. The same weight at the Bridgestone in the 245/70-17, a size fitted to the previous generation. That size also opens up Pirelli and Continental. We have Continentals and like them. The Pirelli was a Consumer Reports best pick a few years ago. Fuel mileage was one of Pirelli's standout points in that review. We have Michelins on several vehicles here and while they are a great tire...they know it as it reflects in price. For my usage they offer nothing extra.

On a warm windless summer day 30+ mpg is a given and that number is insane from something with this much frontal area. Much of that number has come from refinements that have reduced internal friction to the point the AFM is literally its default mode. It comes out when timed out, against moderate to stiff winds and hills over 3% in grade and longer than 1,000 feet. It turns very slow now at my preferred 55 mph. Mid 1300 rpm range. Rarely tips back to 5th gear and is overall well behaved.

A 3.08 gear would slow the motor to under 1300 rpm. Take away the leverage that allows her to stay in AFM.
A 3.23 gear is a known.
A 3.42 gear adds a bit over 50 rpm to the cruse rpm, increases leverage and may help keep AFM active longer. Maybe.
A 3.73 gear spins the motor fast enough to cover the stall speed of the converter taking load off the converter clutch but adds 12% to the operating speed and increases fluid temperatures. It's a pretty steep first gear.
A 4.11 gear is like running in M5 and I've done this extended at times. I know this gear will reduce mileage. It will also stay in AFM up a pretty steep hill. I could swap the motor for a Briggs & Stratton with this gear.

Just some early thoughts based on everyone's input and some rough draft research.

The 373 was the first mod I did car had about 40K miles. In the double nickel days I lost 2 MPG on the highway gained in town. That 10 bolt was in the car with the 373 for years and 100K miles. It made about 50 passes at the 1/4 mile@ 14.2 no headers on street tires. So it took some abuse.

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Grumpy Bear · March 5, 2019

3 hours ago, KARNUT said:

The 373 was the first mod I did car had about 40K miles. In the double nickel days I lost 2 MPG on the highway gained in town. That 10 bolt was in the car with the 373 for years and 100K miles. It made about 50 passes at the 1/4 mile@ 14.2 no headers on street tires. So it took some abuse.

Looks like I figured right. It did make some passes. So question. Will you share your before and after highway MPG for this gear and what ratio you took out of her? Some reference points please.

KARNUT · March 5, 2019

Looks like I figured right. It did make some passes. [emoji4] So question. Will you share your before and after highway MPG for this gear and what ratio you took out of her? Some reference points please.

At 60 MPH. 350-350-273 18 MPG. 373 16 MPG. At 60 MPH.

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Grumpy Bear · March 5, 2019

2 minutes ago, KARNUT said:

At 60 MPH. 350-350-273 18 MPG. 373 16 MPG. At 60 MPH.

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Okay I'm having a thick day. Decode please 350-350-273.

KARNUT · March 5, 2019

Okay I'm having a thick day. Decode please 350-350-273.

Stock 350 engine 4V, 350 transmission 273 open rear ended, factory twice pipes. 18 mpg highway. Change to a 373 GM factor limit slip, 16 mpg all at 60 mph, in the double nickel days. No tac can’t tell you the RPMs. With the 454 and the 700r4 it went back to 18mpg.

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Grumpy Bear · March 5, 2019

1 minute ago, KARNUT said:

Stock 350 engine 4V, 350 transmission 273 open rear ended, factory twice pipes. 18 mpg highway. Change to a 373 GM factor limit slip, 16 mpg all at 60 mph, in the double nickel days. No tac can’t tell you the RPMs. With the 454 and the 700r4 it went back to 18mpg.

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That is what I thought but didn't wish to assume. Okay that is a big step. 37% stiffer gear but only a 12.5% reduction. That is very good to know. That was also very good mileage from a bone stock 350. More impressive was the 454. Good job. I had a love hate thing going with the 700R until I found a guy that raced them. He built be one that was a dream. 76 Caprice wagon.

Just on a percentage basis that would be something like Pepper exchanging her 3.23 for a 4.56 and that taking the life time average from 27 to 24 mpg. Still a good number. But we won't be going that low.

KARNUT · March 5, 2019

That is what I thought but didn't wish to assume. Okay that is a big step. 37% stiffer gear but only a 12.5% reduction. That is very good to know. That was also very good mileage from a bone stock 350. More impressive was the 454. Good job. I had a love hate thing going with the 700R until I found a guy that raced them. He built be one that was a dream. 76 Caprice wagon.

Just on a percentage basis that would be something like Pepper exchanging her 3.23 for a 4.56 and that taking the life time average from 27 to 24 mpg. Still a good number. But we won't be going that low.

The 700R4 didn’t stay in after the wife started working and bought her star fire. I went back to the 3 speed transmission for weekend warrior duty. That’s when most of the drag racing was. I got stupid and put the 454 in a nova and the 350 back in the impala and sold it.

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