whats goin on everyone i have an 84 chevy with the 6.2 and i am puttin a 6 inch lift on it and i was wondering what gears do you think i should put in it 3.73's or 4.11's?

gearing depends on tire size. WHat are you putting under it? I'm looking at 4.73 or better with the 38's I will be running once I have the money for the axles.

Also, what axles do you have? regearing 10 bolt axles is polishing a turd because if you run 35's that have a tread pattern more aggressive than BFG muds you're going to start breaking stuff.

well i have the 10 bolt right now but i am swappin out for 3/4 ton axles so i was just hopin to get some with 4.11's and just leaving them but i wanted to see what everyone else thinks

4.11's will work with a 35" tire, but if you offroad you might wanna consider either regearing your t-case or putting in a doubler.

What tranny are you running? the gears depend on what you plan to do with the rig.... if this is your daily driver i would stick with the 4.11s, if you just plan to wheel the rig you may consider something a bit lower, or dual cases, or dual trannys. its all in what you can afford, and makes sense for ya; chances are finding lower gears will be the easiest option

well the truck has a newer 700r4 in it so i was plannin on runnin that until it blew and it will pretty much be a daily driver depending on what kind of mileage i get out of it. right now it has 4.11's and it is the stock other than that. and it is gettin about 16.5. but i am plannin on puttin heavier duty axles in it and i am also plannin on turbo charging it and maybe more. so eventually i want to put a nv4500 tranny with the heavier duty axles to kinda give me a reliable set up. and it will have 35's.

oh and i am also plannin on puttin stacks on it. lol ):h

16.5 mpg? That's low. How sure are you of your accuracy? Should be getting 20 mpg or more. I drove from Salt Lake City to Los Angeles (900 miles) in a '87 6.2, 700r4, 3.73 and got 25mpg @ 65mph.

16 is really low... You should be getting much better mileage than that. Could be a sign of injection pump failure.

I am still averaging about 26 mpg... That's on my daily drive to work (20 miles each way, going about 55 mph with a stop sign about every mile). You have 4.11 gears, though, so your mileage will be lower, but it should still be getting 20+ mpg.

I thought the engine was bad on that truck... Did you get it going or was that before the engine trouble?

The stacks should be interesting...

well the truck has a newer 700r4 in it so i was plannin on runnin that until it blew

right now it has 4.11's .

and it is gettin about 16.5.mpg .

Does your lock-up work properly on your trany ????

Your lock-up should lock at 45-50 mph your should ear the motor rev go down at that speed
+
When your on HW at 60mph press gently on the brake pedal , you should feel-it disengage .


If not it can explain your poor milage.

just my .02 cents

Ed

well now that you say that tigman i didnt rev down at all so that could be it. and that was before the motor took a you know what on me. and the accuracy should be right on but you never know. i used a calculator to do the math. i also thought that was pretty low for a 6.2 when i got it but it was still better than the truck i had before so im not complaining.

im suffering from the same problem, my truck has 3.08's with 31's (snow tires), and has a 700r4 and im only gettin like 13-14 maybe 15 if im lucky, my truck runs great, has good power, but just aint gettin that great of milage

im suffering from the same problem, my truck has 3.08's with 31's (snow tires), and has a 700r4 and im only gettin like 13-14 maybe 15 if im lucky, my truck runs great, has good power, but just aint gettin that great of milage



Wow... That is way too low. You should be getting much better fuel economy than that... I think I'd start looking for fuel leaks or maybe fuel thieves (don't laugh, it happened to me and they pumped my tank dry :eek:)...

I can't make my truck get mileage that bad even if I try... Can't get it below 20 mpg, and to get it that low I have to keep the pedal on the floor for hours. ):h

yea i thought 16.5 was bad but you have a serious problem.

im suffering from the same problem, my truck has 3.08's with 31's (snow tires), and has a 700r4 and im only gettin like 13-14 maybe 15 if im lucky, my truck runs great, has good power, but just aint gettin that great of milage

Hi yes thats way too low same setup on my 85 pickup and i average 28-29mpg on a regular base .
Now with my Crewcab - th400 - 4.11 diff - 4800pds 16-17 mpg i only run it for 2 weeks):h

Blue Thunder i also thought that was pretty low for a 6.2 when i got it but it was still better than the truck i had before so im not complaining.

maybe but check at your tranny oil temp , if the lockup does not engauge it produce more heat and heat is a killer for a th700


Ed

my torque converter locks up fine, i have it on a toggle so i can control it, i have a locking cap on my tank, and no fuel leaks. now i have another question, could it be that the 3.08's are too low geared for my truck? im getting a set of either 3.73's or 4.11's, im not sure yet what they are. the only problem i am having is my trans doesnt like to stay in od, now i have heard this is a common problem for these trucks, so i know that doesnt help.

one more thing, could it be in the timing as to why the low milage?

It is most likely a combination of factors... Timing could be a small part of it, but not a large one.

The lower gears may help... The 3.08/700R4/35" combination is really steep. It must feel just powerless with that setup.

Did you adjust the governor on the transmission to match the gears and tires you've got? If not, you should. It could really improve your mileage.

Also, I assume your brakes are adjusted correctly...

my trans always kicked in and out of OD, i run 33's with 4" lift...does ok unloaded without a trailer...with a trailer..forget it. a waste of time to even attempt hauling anything. i fixed my trans shifting problem by installing a b&m shift kit set on towing...it did better, but not good enough for me, so i just went ahead and installed the heavier spring for the drag setting. works great now.

Hey, holtzer1... Been a while since I've seen you post... Glad to see you are still poking around on here... :) You still got your 6.2 or did you pull it yet?