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have a cammed 5.3 ( ss2, full exhaust, CIA) with a 4l80e behind it ( bluecat tuned, stock 2600 stall) in a 08 silverado 1500 with 35s. stock gears are 3.73s usually 35s want 4.56 but with the short first gear in the 80e, would i better off with 4.88s? will be changing stall but not any time soon, dont tow basically anything but this trucks a pig off the line, rolling 40+ is very very strong. i dont do alot of highway driving but some so dont need to knock down the 15mpg i get rite now at 65mph.
I don't think you'd be unhappy with 4.56's.
1st gear is tall not short. but i know what you mean.
4.88s or 5.13s work very well if you never ride at 70+mph.
If you ever plan on riding at 70 then 4.56s work pretty good.
4.56s would be 2000 rpm at 60 and 2300 at 70
4.88 2150 at 60 and 2450 at 70
5.13 2250 at 60 and 2600 at 70.
3.73 1650 at 60 and 1900 at 70.
i do run 70+ once in a while.. rite not 65-70 is like 1500 rpms. we dont have alot of highway here but once in a while we run 300 ish miles to rockford ill would like to be able to atleast pace highway traffic lol
I ran 5.13s with 30.5" tall tires running a 350/4L85E. No problem running 90+ if I wanted to. Very little difference in fuel mileage between 2,000 rpm and 3,000 rpm pushing a brick down the road.Quote:
Originally Posted by ehall8702
I second the 4.56's. You "can" run into issues with the taller (numerically larger) gears. The pinion has to become smaller and smaller. Less contact area. Not a big deal if you are running racing equip like a 9 inch or industrial axles and don't care if they make noise.
Here is my favorite gear calculator. It may look like a mess but it is easier than you think. Go to the left column at number one and select your trans. 4L80 and also select it for the right column. It will auto load the factory stock gears unless they have been changed. If they were you can change them there. Go through the steps and on the left use the stock gearing with stock tires according to your door sticker. Put your options on the right. Oh NEVER put down what your tires says. ALWAYS measure diameter with tape measure. The only tires I have ever seen match what they said were M/T's and I think some Goodyear off road tires. Regardless use the tape to confirm. I have had many off as much as 2 full inches.
Check what you have. Enjoy
http://www.grimmjeeper.com/gears.html
i may be fine with 4.56s i guess. i believe im limited to 4.88 at largest with the 10 bolt (8.6 i think) diff. my truck has no lack of power. was out playing today and the 40-100mph+ is unreal. just need to unhook that anchor behind me under 40 lol. tires are 325/60r20 which is supposed to be 35.4x12.8. ill have to measure them. i had intentions of possibly goping 37s in the future but these 35s required sum trimming with a 7.5 lift as it is , so not going any bigger, and its edging on unpracticle with size as it is now. still have to change the input gear on my tcase to bolt up to the 4l80, just have a floor shift bolted up now and a ground jumper to front actuator so i atleast have 4x for now. this truck has been a project a little at a time but still needed to get me back and forth to work at the same time so sum less than ideal setups have went on. i appreciate everyones help so far, believe ill go 4.56 and save for a proper 3600 10" stall for my truck and end up with a tire smoking ride again.
I had one of those little 10" converters. Absolutely was not a fan. Ended up having a high str 2,800 built out of a B82 core. Far better driving converter and still roasts the tires.Quote:
Originally Posted by ehall8702
yeah im not versed in trans stuff, so that a reason i haven't ordered anything until i can get definant answers on what is going to work, i hate wasting cash. ill pull trans any time to change stuff but that $1500 hurts if i make the wrong choice! ill see how the stock 2600 stall does when i change the gears in a month or 2, then go from there. its a huge truck, i dont need to burn off $400 a tire tires off too much, but dont want a complete dog
well did 4.56 gears, lets say i wasnt happy at all. 0-40 is a complete dog still tho, faster than a stock truck with 6 speed and single turbo and intercooler with garbage tune. My 3k and up is still stupid, itll break back tires loose shifting into 2nd and keep em spinning for a bit if i hold it. ive been sideways a few times with a downshift and full throttle passing someone on highway. So here i am with cash ready, looking at new gears. 4.88 or 5.13? i say 5.13s but then im worried about contact patch of the tiny pinion. i dont offroad more than trail riding, but i do get kinda dumb on the roads where its more likely to braek stuff when i hook up. truck weights in at 7200lbs unloaded also. Another factor now is the guy with the turbo setup wants it all off his truck and returned close to stock giving me all turbo related stuff and an extra turbo for the labor to return to a "normal" truck he says. guy he bought it from put the turbo stuff on, then he had to sell truck to move out of state, old guy who bought truck says its too much for him and only wanted it for a winter truck. sorry off topic a bit, but how reliable are 5.13s in a dialy ( i dont drive but a few miles a day and hardly ever on highway, but may once in a while) will pull my camper a few times a year but is tiny and weighs nothing, my ATV pulls it easily.
There is a 9.5 14 bolt option that’s bolt in for that truck. They are pretty reasonable at a salvage. I’d either go with it or a 9”. Either one is way stronger than a 10 bolt. I’ve also used a full floated 14 bolt out of a 2500. It takes quite a bit of machine work on the hubs to get 6 lug wheels to fit but you don’t have to worry about anything breaking on it.