Swapping in 40k 4.8 in Moms '05 Z71 Tahoe

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The 4.8 has no where near the torque curve the 5.3 has. The 4.8 required much higher RPM to get comparable acceleration. The 4.8 was really just a dumb motor IMO, it was gutless under 2500RPM. The 4.3 V6 had much more useable torque at lower RPM. Heck even the 3800 V6 feels like it has more usable low rpm torque than the 4.8. I’ve known quite a few people who’ve had the 4.8 and they couldn’t stand it. Sure, it got 1mpg better EPA rating than the 5.3, but in the real world the 4.8 gets less MPG trying to keep up.
 
The 4.8 is a strong engine for being a "mid level" engine. 295 hp and 305 tq compared to it's direct competitor which would be the 4.6l ford making 240hp and 290 tq. The only issue I have with mine is it has the 3.42 gear matted with the 4speed auto, I wish it had atleast a 3.73.
Interesting you would say that. Within the next month or so I’m taking my 2013 4.8 silverado 4 speed 3.42 in to get 3.73 gears. Because its four wheel drive it wont be cheap (about 5k), but it gets me another 1000 lbs GCWR for towing and 5000 bucks is a heck of a lot cheaper than a new or used truck. The prices for trucks right now are awful for buyers. When I got my 2013 new GM was still in the early stages of getting that cylinder deactivation system working right on the 5.3. I wanted to avoid that. From what I remember at the time (all the griping and people getting tunes to shut it off) I’m glad I did. Also, the six speed was still relatively new at the time and I had had good luck with the 4L60E in the past. Mileage does suck on this unit though. 13 in the city.
 
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Here are the torque curves of the 5.3 and 4.8. Their differences in torque pretty much follow along proportionally with their differences in displacement, except the peak torque for the 4. 8 is at a higher RPM than the 5.3. Certainly 3.73 gears will help wake up a 4.8. The torque curves are also for two different model years, so some differences. Is one a dog and the other not a dog? I don’t think so. I have a 6.0 with 3.73 gears.

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Here are the torque curves of the 5.3 and 4.8. Their differences in torque pretty much follow along proportionally with their differences in displacement, except the peak torque for the 4. 8 is at a higher RPM than the 5.3. Certainly 3.73 gears will help wake up a 4.8. The torque curves are also for two different model years, so some differences. Is one a dog and the other not a dog? I don’t think so. I have a 6.0 with 3.73 gears.

View attachment 38520View attachment 38521
Please stop posting actual data … That’s mean. 😠
 
Interesting you would say that. Within the next month or so I’m taking my 2013 4.8 silverado 4 speed 3.42 in to get 3.73 gears. Because its four wheel drive it wont be cheap (about 5k), but it gets me another 1000 lbs GCWR for towing and 5000 bucks is a heck of a lot cheaper than a new or used truck. The prices for trucks right now are awful for buyers. When I got my 2013 new GM was still in the early stages of getting that cylinder deactivation system working right on the 5.3. I wanted to avoid that. From what I remember at the time (all the griping and people getting tunes to shut it off) I’m glad I did. Also, the six speed was still relatively new at the time and I had had good luck with the 4L60E in the past. Mileage does suck on this unit though. 13 in the city.
That is a ridiculous price! Shop around, I hate seeing anyone ripped off. I had a 4x4 shop change out rear gears in a Mustang I had. It was under $500
My Coworker had a 4.8 in his pickup. He changed out the gears to 3.73 and it woke up.
 
Interesting you would say that. Within the next month or so I’m taking my 2013 4.8 silverado 4 speed 3.42 in to get 3.73 gears. Because its four wheel drive it wont be cheap (about 5k), but it gets me another 1000 lbs GCWR for towing and 5000 bucks is a heck of a lot cheaper than a new or used truck. The prices for trucks right now are awful for buyers. When I got my 2013 new GM was still in the early stages of getting that cylinder deactivation system working right on the 5.3. I wanted to avoid that. From what I remember at the time (all the griping and people getting tunes to shut it off) I’m glad I did. Also, the six speed was still relatively new at the time and I had had good luck with the 4L60E in the past. Mileage does suck on this unit though. 13 in the city.
There is no way it should be anywhere near $5k. Parts and labor you should be around $1k and that's being generous. I've never paid more than $250 to have some gears setup.
 
Calls for 6.2 Hours to swap gears in the front differential, Ain't gettin' that done for $250! A Yukon YG GM8.25-373R gear set runs @ $433, Yukon master overhaul kit runs @ $275 which doesn't include the axle roller bearings & seals which can easily cost $200.

$620 in labor
$433 in gears
$475 in small parts
$20 in lube
$1548 in the front diff alone

Rear diff
Yukon gears...$300
Master Overhaul....$253
Axle Bearings & Seals....$60
Lube......$30
Labor.....4.8 Hours @$100.....$480
$1,093

Didn't add any sales tax as it varies.....But roughly $2,650 before tax, A FAR cry from $5,000 though.
 
Calls for 6.2 Hours to swap gears in the front differential, Ain't gettin' that done for $250! A Yukon YG GM8.25-373R gear set runs @ $433, Yukon master overhaul kit runs @ $275 which doesn't include the axle roller bearings & seals which can easily cost $200.

$620 in labor
$433 in gears
$475 in small parts
$20 in lube
$1548 in the front diff alone

Rear diff
Yukon gears...$300
Master Overhaul....$253
Axle Bearings & Seals....$60
Lube......$30
Labor.....4.8 Hours @$100.....$480
$1,093

Didn't add any sales tax as it varies.....But roughly $2,650 before tax, A FAR cry from $5,000 though.
Thanks a lot man for the heads up. I really appreciate the time taken to break all that down.
 
Calls for 6.2 Hours to swap gears in the front differential, Ain't gettin' that done for $250! A Yukon YG GM8.25-373R gear set runs @ $433, Yukon master overhaul kit runs @ $275 which doesn't include the axle roller bearings & seals which can easily cost $200.

$620 in labor
$433 in gears
$475 in small parts
$20 in lube
$1548 in the front diff alone

Rear diff
Yukon gears...$300
Master Overhaul....$253
Axle Bearings & Seals....$60
Lube......$30
Labor.....4.8 Hours @$100.....$480
$1,093

Didn't add any sales tax as it varies.....But roughly $2,650 before tax, A FAR cry from $5,000 though.
Summit has the front gear set alone for $180. The prices you quote are pretty high. Also you are quoting replacing every single part which we both know probably wont happen.
 
9mpg is a little low, They typically get around 12mpg. If you put a 6.0L in your truck....You'd get close to the same 19mpg. A 4L60E is quite an efficient unit compared to a 4L80E then you got the bigger differential & lower gears + the additional weight of a crew cab 2500.

I put a LQ4 6.0L in my dads 2003 Tahoe to replace the leaky L59 5.3L, Still gets the same 16mpg average it always got....Just more grunt.

I'm swapping back to a 4L60E in my Camaro because the 80E is so power hungry.
Agree. My 2006 Sierra Denali with the 345hp LQ9 6.0L and AWD gets 13.5 combined mileage with a few bursts to 14-14.4 with more highway use. I only got 9-10 mpg when towing my RV (30' long).
 
Hey, thanks a lot for the heads up. I went to Yukon gears website, found a distributor, and it looks much better. This is after two shops quoted me 5000 bucks (though that did include an extra 500 for limited slip install). Check out the itemized estimate...much better!
 

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I do more differential builds than most Mechanics.....You may have been given the "Go Away" price
Summit has the front gear set alone for $180. The prices you quote are pretty high. Also you are quoting replacing every single part which we both know probably wont happen.
If you want to run cheap parts....Go for it. I use & stand behind Yukon & OE only.

I replace ALL bearings & seals with top shelf stuff, Again.....My name is going on it & that means a lot more to me than being the cheapest guy in town.
 
I do more differential builds than most Mechanics.....You may have been given the "Go Away" price

If you want to run cheap parts....Go for it. I use & stand behind Yukon & OE only.

I replace ALL bearings & seals with top shelf stuff, Again.....My name is going on it & that means a lot more to me than being the cheapest guy in town.
Im not disagreeing with you just stating that most mechanics out there wont be as thorough as you. Or use the best parts. I chose to go to a 4x4 shop due to the fact they do gear swaps all the time and are used to setting them up right.
 
When it was new, I had the front and rear gears swapped out on my 2005 Z71. Went with Yukon 456 both ends, I was afraid the 4L60 wasn't going to last long with all that gear hunting. Also swapped out the servo with the corvette one. I am running a 32 inch tire so I believe it's geared more like 390. Cost me $1500 back in 2005.
 
I do more differential builds than most Mechanics.....You may have been given the "Go Away" price

If you want to run cheap parts....Go for it. I use & stand behind Yukon & OE only.

I replace ALL bearings & seals with top shelf stuff, Again.....My name is going on it & that means a lot more to me than being the cheapest guy in town.
I think that’s exactly what it was...the go away price. I am now toying with 3.73 vs 4.11. One of my questions would be if the trucks comp can even be programmed for the 4.11 since it wasnt a factory option (3.73 was). 4.10 used to be a standard GM option, just not for the half tons in 2013.
 
HP-Tuners or EFI Live would have no issue programming for 4.11 gears
After looking through GCWR and seeing that the 4.10 had a 2000 lbs capacity increase over my 3.42 I decided to go with the 4.11. When trying to load conservatively we were 300 pounds over the 11,000 GCWR of my current 3.42s. The 4.10 13,000 GCWR rating will give me some extra cushion. It will allow truck and trailer to (if desired, but not happening) be loaded to full GVWR and still 500lbs left over. Thanks for heads up on speedo calibration.
 
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