GMCtrk

iTrader: (27)

No I already had 4.10s with the 4l60e. As I said, all factors were held equal between the two setups just the transmission change. The 4l80e has a lower OD ratio so RPMs will be a little more. That and other small factors probably led to the MPG decrease. With the 4.10s I usually get about 15 mpg on the highway around 75 mph turning close to 2500 rpms IIRC. With 3.42s I bet I could get 20 no problem.

seh6183

What to do, what to do. The truck will only ever see bolt ons and MAYBE a homemade 70mm turbo kit on 6 pounds. Im not interested in a stall or gears or launching. Its just my DD. Maybe I should just keep running stock 60e's with vette servos to retain my MPG around town. The truck will never be run at the track. (well maybe once heh)

GMCtrk

iTrader: (27)

If you want MPG just keep it near stock, seriously.

With a stock LQ9, tube, 4l60e, and 3.42s I was getting ridiculously awesome gas mileage. I dont remember city numbers but I was pulling down 23+ MPG on the highway

seh6183

Tube?

I was reading that the vette servo helps prolong the life of the tranny by reducing slip in between each shift. I understand that it will increase the firmness of each shift but I cant exactly find an explanation of how much firmer. I want it to be totally comfortable and near stock, as I let my girl drive the it every once in a while.

What I was going to do however was have my tuner increase the line pressure dramatically at higher RPM so that it barks the tires when im on it, but when I want to ease around it feels stock.

So avoid any type of stall at all when I want to conserve MPG? Even a low stall? The only reason I ask is because I want to get the servo, converter, or any other tranny mods sorted out while the tranny is out.

GMCtrk

iTrader: (27)

No from what I've read on here I think you can do a mild stall in the 4l60e, like the modded trailblazer stall, and maintain very similar mileage. I had a yank 3600 in my 4l80 and was getting 8-10 mpg city on winter blend gas.

TX Tahoe Z71

iTrader: (28)

Change shift firmness with servos and adding washers in a shift kit, not by turning the line pressure up dramatically. Also, barking the tires at shifts on a stock transmission is just asking to break hard parts.

The vette servo is a fairly easy install and can be done with the transmission still in and not drained (though you will lose a small bit of fluid). It's cheap ($16) and a good mod to make to increase trans life. Do that first, then decide if you want it firmer; if so, look at the Transgo HD2 shift kit.

seh6183

Thanks for the info. Being that I need a new tranny anyway, Ill just do the vette servo before I put the new tranny in. Should I look at 4l65's or anything? Just looking for the best bang for the buck here. And do you personally know anything about the trailblazer converter/stall?

BlackGMC

iTrader: (31)

I went from 60 with a stock TC to a 80 with a 3600 TC and i only drop 1 MPG with 50/50 city/highway driving. The Rear gears (4.10s) stayed the same. So i went from ~16 to ~15 mpg.

JFOLM

iTrader: (8)

OP,
Just making sure you caught the post earlier. 80e's do not have servos. They are talking about 60es when they mention them.

seh6183

Well damn... I drive mostly in the city and a poster earlier said he lost about 3mpg city with the 80. If I could lose 1 mpg in the city by doing an 80 I would love to do the swap. You never know when you get an itch and want to turn the boost up I would love to put in an 80 and get it over with once and for all, I will never see enough power to break one of those... But NOT if im going to lose a precious 3mpg in the city.

A buddy of mine just picked up an 80e for 350 bucks off the boards. Was that an insane steal? It seems like it to me.