******double post***************

 

whats up guys....i just got in from work....thanks for the support. to texas guy 001 i am going to keep the tire size and to andyman7931 i did talk to the shop that installed the gears and the owner said that he would come out to my place to look at the gears and give me and answer this friday afternoon. the owner asked me what happened and i told him what happened and he sounded shocked that it broke. to lcam-01xa my trans has a metal plate on it that says aode/w on it. to andyman7931 and 6cyl bill i will think about the 4.10 gears. to skyfox10 what does it mean when you said the rpms are so low that it keeps the computer in an open loop. i drive on the freeway to and from work around 7 miles so i don't want too much gear in it to where it will start to put a damper on my gas and mileage.....thanks for reading my post guys and for the support.........talk to guys later........time to have me some dinner..............

 

Here is a quote from our beloved conanski:

 

I must really be the odd man out.

I LOVE the 3.08 gears with the 5 speed, and the 302 in my old half ton. I can go over 100mph (not like i do often though!) and while cruising the highway (speed limit 110km/h here) I can average 20 mpg. (hand calculated, with filling the tank to the brim).
I can spin the tires on pavement in first and second gear, and do a pretty mean burn out (not like i do that often either) if needed!

Mind you the last thing my old truck towed was a fishing boat, and now the only thing that goes in the box is a few bags of garbage, so I dont use it as heavy as some of you may.

 

When I first got my 95, I would run 20 miles at a time over 100mph. That was with 3.55 gears. I'm sure 3.73 could do it, but who really drives like that? Where do you live? What are the grades like and how do you drive? 20mpg. And unlike my tastes in baskets, hand calculated doesn't do anything for me in mileage. How do you calculate?

 

I dont run over 100 very often, just tried to make the point that the truck seems to have all the speed and power I personally need! (all while getting pretty kickass economy when need be!)

I live in Saskatchewan, Canada, we dont have grades here! Pure flat land!

How do i calculate mileage? Well i fill the truck up, drive it till near empty, fill it up again, write down the miles ive went and the fuel I used, then do the simple math.

Then I repeat a few times over, to get a reasonable average.

 

Well, I accept your method. I don't care for people making mileage claims from one tank of gas. I know my truck wont make 15 on the highway but I've gotten 18 on one tank here and there because I rocked the truck to get a few more gallons in on the previous fill.

I guess I might be happy with the 3.08 gears if they raised the speed limit to 80mph and I never drove though any mountains. Hit a hill at 1700rpm and you gotta downshift. Hit that same incline at 80mph, getting over 2k rpm, and she just keeps gaining speed.

 

You think these trucks are bad aerodynamically, try mid- to late-'70s fullsize Chevy trucks, like pushing a brick wall through the air. I had one of those a few years back, with the TH350 trans the 3.08 or 3.07 rear gears were a blessing, she would pull steady 20 mpg running with the big rigs on the freeway. I did set up the engine for low-rpm torque tho, and it was definitely not your factory emissions-crippled small block, she had no problems lighting up the 33" BFGs on hot and dry pavement So don't kick the 3.08s to the curb quite yet, they have their place and use, and yes I know mine was no Ford but the principle is the same - with these pathetic power outputs the factory gave us you pretty much have to chose gears to negate the engine's deficiencies instead of complementing its strong areas.

What you do is disconnect the cable from the transmission, pull it out, and replace its plastic drive gear - they make different gears with different tooth counts to match different rear axle ratios.

You do have more gears to choose from tho, and your 1st and 2nd are likely lower than what we slushbox guys run, so that helps a lot. For you 4th gear is your work gear, and the OD is just for flying low on the freeway. Your freeway speed limit is about 70 mph so nothing too fast really, so with a light truck you don't see much engine load and so your fuel economy is good, nothing out of the ordinary there.

I think you misread his post - he was simply stating that he can go faster than 100 mph without revving the **** outta the engine, his 20mpg economy actually happens at his freeway speed limit of 110km/h which is 70 mph - I dunno about you, but if I had a halfton with OD gear and it didn't get at least 20 mpg on the freeway I'd be tearing into it the first paycheck available. And hand calculations is done like this - fill up tank, drive to empty, fill up again, drive to empty again, and keep repeating this from the UP to the Gulf of Mexico, then you divide the distance you traveled by the total amount of fuel you dumped into the tank and here's your 20mph fuel economy. It's the same way I know my old Chev would get 20 mpg from Detroit to Dallas and back, and that my diesel averages between 18 and 20 mpg as long as I keep her in OD at 1900 rpms.

 

Well, for mileage purposes I have no problem comparing a ford and a Chevy, but I think your illustration doesn't fit the Gen9 Fords' ECM's tendency to richen the fuel mixture when the engine is lugging.


I'm actually quite familiar with this method of finding fuel economy. I was asking how preppypyro was calculating his mileage.

 

Actually it does, this is a common thing when the engine load increases, even carburetors do it - whether it's power piston (Q-jets and Edelbrocks), power valves (Holleys and such), or ECM running off the MAP signal, the moment the vacuum goes down the fuel delivered to the cylinders increases. But my beef was with the rather restricted factory calibrations (whether it's a GM or a Ford, they all do it) that operate the engines in a way that we can't use them to their full potential - once you're past these limitations new driveline combinations become possible, in other words my comment was directed towards those people who said 3.08s do not belong in a pickup truck and that we should all be running 3.55s and more...

I'm glad that we agree on this

 

I don't know much about carbureted engines, so this is news to me, thanks for clearing that up.

I still think that running 3.55's and beyond sounds like a good idea, not that there isn't a place for 3.08's and lower. I guess to me, a truck is designed to impact the world around it. IE, impacting that load of firewood, or impacting that 10k trailer behind it. It seems like a greater mechanical advantage would help this happen.

I suppose you are right that every gear ratio has it's purpose, maybe my idea of a trucks purpose is a little biased.

Btw, what engine were you running it that Chevy? I wouldn't mind seeing mileage in the 20's with my truck, but I'd settle for over 15.

 

Skyfox said something I think is interesting. The slower I go when I hit a hill, the more gear I need. If I hit a big hill going 35- 45, I have to put the truck in second gear. However I can hit a MASSIVE hill going 60 and not come out of OD. Take the same MASSIVE hill going 70 and the truck has an even easier time.

Considering the low revving I6 and low gears, you would think it would be opposite!!

 

Got a question for y'all...I got a 95 with the 300 and I'm running 31x10.5R15 mud tires on mine. I"m not sure what gears i have in the rear end but whatever they are they are stock. What would be the best gears to run in this setup? I do pull trailers occasionally, up to 5000lbs, but mostly do a lot of highway driving and used as a farm truck off road as well. Any advice would be awesome!

 

Hi jjarboe01. I have the same size tires and type and I have a 300. I made the mistake of installing a 4.11 gear set. Way too low.

Since you pull heavy loads, I recomend 3.73.. But no lower than that. The 4.11 really narrows down the 300's powerband. It kills highway power the milage.

3.73 sounds spot on for your application. If you didn't tow, I would say 3.55.

 

Yes.. but that use is in a vehicle that doesn't have an overdrive transmission. Here are some numbers for comparison. With 28" tires, 3.08 gears and a 3-speed trans the engine is turing just over 2000rpm at 55mph.. assuming no TC slippage. With an overdrive trans like the AOD/AODE/4R70w that same combo needs 4.56 gears to achieve that same engine speed in OD!

So for anybody that has a 5.0 truck with 3.08 gears keep it out of OD unless you're cruising on a flat freeway.. it will actually return better milage.