Gear Swap

BLACK DEATH · November 7, 2009

i have a 93 chevy full size truck with the 4.3 engine and it is auto. the rear has 3.08 gears. Did all 4.3 trucks for this year come with 3.08 gears? Would it be better to go with 3.42 for everday use? Im sure the 3.08 is good for freeway but i dont drive long distance on the freeway. Also it seems that its a turd on the freeway with 3.08 gears. Maybe the 3.42 will get the rpms up a little and not have to downshift to pick up speed. It gets decent fuel economy around 15-17 in the city. I wonder if the 3.42 will hurt the fuel economy at all or help?

Nytemare · November 7, 2009

Yes gears will bring up your revs....give you better pick up on the road and make your truck not act like a dog. 3.42 wont be that big of a difference... your better off going with 3.73's

And Yes....you will affect your fuel economy...you will actually lose 1-2 mpg with the 3.42 and 2-3 mpg with the 3.73

So ask your self if you want to get up and go....or put along and save fuel.

BLACK DEATH · November 7, 2009

When i did some mph rpm calculators the rpms didnt go up too much, i dont see loosing that much mpg in the city using 3.42. I dont see using 3.73s as that would be too much gear for this motor. MAybe the freeway long travel i may loose 1 mpg.... Any other input from anyone?

Zembonez · November 7, 2009

I went from 3.23 gears to 3,73 gears in my truck and the mileage hasn't changed at all in the last 2500 miles. Just like it always has been. Mine has a 4.8 though. The 4.3 might not react the same.

BLACK DEATH · November 8, 2009

I went from 3.23 gears to 3,73 gears in my truck and the mileage hasn't changed at all in the last 2500 miles. Just like it always has been. Mine has a 4.8 though. The 4.3 might not react the same.

How do you like the gears though now? Do you like em better or did you make a mistake?

Zembonez · November 8, 2009

I went from 3.23 gears to 3,73 gears in my truck and the mileage hasn't changed at all in the last 2500 miles. Just like it always has been. Mine has a 4.8 though. The 4.3 might not react the same.

How do you like the gears though now? Do you like em better or did you make a mistake?

Absolutely perfect. Good low end and it's not all wound up on the highway.

Since your truck is a 93, I'd bet you could find a rear end with factory 3.42s in it and do a swap for pretty cheap. I know a lot of those trucks came with 3.42s from the factory. My 01 Silverado was a 4.3 with 3.42 gears. It was great around town but nothing will make a 170 HP engine perform great on the highway.

BLACK DEATH · November 8, 2009

Yeah, thats what i did, was find a complete 3.42 rearend from the same truck platform. It was a free rearend actually as I parted out a truck and broke even on all the parts. The gears feel tight too so thats even better as this 3.08 has issues with the pinion bearing. But your right nothing cheap can improve the low hp output of this 4.3 on the road but i mostly do city so im glad ill go this route and its my daily driver beater. If i dont like it ill go back to the 3.08s as I have a another complete rear with 3.08 too. thanks for your input

Also do you wanna sell the 3.23 gears?

Zembonez · November 8, 2009

Yeah, thats what i did, was find a complete 3.42 rearend from the same truck platform. It was a free rearend actually as I parted out a truck and broke even on all the parts. The gears feel tight too so thats even better as this 3.08 has issues with the pinion bearing. But your right nothing cheap can improve the low hp output of this 4.3 on the road but i mostly do city so im glad ill go this route and its my daily driver beater. If i dont like it ill go back to the 3.08s as I have a another complete rear with 3.08 too. thanks for your input

Also do you wanna sell the 3.23 gears?

I think you'll be very happy with the swap.

Spurshot · November 9, 2009

Since you already have the 3.42 rearend, go for it. It'll cost you about 3 beers worth to install it. Get 'er done. You'll like the improvement. But, I think you could have gone to 4.10s if you don't do much highway driving. Especially if you have large diameter tires.

gabe74gt · November 10, 2009

its better to go for some higher configuration for lasting improvements and power. for this you just need to spend some bucks at first and then all is to maintain

BLACK DEATH · November 17, 2009

Ok on the post above but I think I get what u meant. I may have found a 3.42 rear with posi so I may hold off for now, even though this govlock posi may be a waste in this puny motor.