2001 ECSB 5.3 4L60E 3.42 rear with G80 & 149k on the clock. This is a daily driver, stock wheel/tire set, 85% in town (<55mph) 15% hwy (75mph), no track time or street racing, just like to get set back in my seat every once in a while.

I'm planning on upgrading my G80 with either a truetrac or valuetrac from Ron's and while I'm at it, I'm wondering if it would be worth swapping gears or not. I'd like to keep my mileage up but since 85% of my driving is below 55mph, I've read where shorter gears could help. What do you think, keep the 3.42s or go up to 3.73 or even higher? I'm thinking it may not be worth the cost.

Also, If I'm planning on doing the LSD swap in my garage, do I need the master install kit from Ron or not? It comes with all those bearings that I don't know if I need or not.

Thanks!

 

If you dont race just keep it were its at and buy a car for that seat of the pants feel.

 

If it were me I would regear to 4.10s. .

 

I forgot to mention, I have a Circle D 278 converter in my near future also, probably 3000 stall speed.

And buying a car is not an option, unfortunately.

 

if your definately doing gears, and your driving is mostly below 55mph i would get the 4.10. it will get you rolling from a stop easier, and keep the rpm below 2k rpm at 55mph. 2k rpm and up is where these trucks seem to start losing their MPG. keep it at 1900 rpm (whatever mph your gears allow at 1900) and id be willing to bet your mpg will go up.

 

I run the 3.73s in my truck. It gets it going (kinda) fast and running everything stock I got 27.8MPG on a trip to the casino. I got 26 back. I would say we drove 100ish miles and did 55 almost the whole way and it was EXTREMELY hilly. I get consecutive above 25MPG in town and sometimes 30 on the freeway. Its a bone stock 2000 silverado ext cab with a 4.8L.

Your driving style makes much more of a difference than any gear will. If you are a speed racer and just have to go fast and don't care about gas (even know you are burning 1.5X the gas AND not getting there much faster) then I would get the 4.10. There have been a few times I have been offloading where 4.1 would be nice, though I just stuck it in low lock and that was good enough for me :p . For me personally I see the 3.73 as an all around good gear. Not to high not to low. Still have power to move while cruising at 65-70 you can still pull good mileage. Just my thoughts on it.



Michael

 

I got 3 poll responses for 4.10s... not quite the voter turnout that I expected.

I'm still undecided on this and still have a month or so to decide, but this is what I have come up with for research...

Going from 3.42 to 3.73 will add approximately 175-200 RPM at highway speeds, 3.90 ~300 PRM, 4.10 ~400 RPM at highway speeds. They recently changed the speed limit on I-70 to 75mph across KS, so that puts me running around 80 mph. With the 3.42s I run ~2150 RPM; with 4.10s I would be ~2560 RPM! I'm guessing that would tank my mileage on a 300 mile trip one way.

Now all I need is a calculator for MPG loss per RPM gain! I know that I shouldn't focus on highway MPG when I said that 85% is <55mph, but it's hard not to do.

Do not many people run the 3.90 gear ration on here?