Any Transmission Guys here?

[SoonerP226]

It's crazy to think that 30-40 years ago, the majority of mankind didn't know what their vehicle's mpg even was, and could care less if they did know lol.

It was longer than 40 years. Gas was cheap enough that nobody cared 'til the early '70s when they had to wait in lines for gas, then crappy little poopboxes became all the rage. That's also when you got the EPA and the Feds began mandating mileage requirements.

It moves in cycles as the price of oil goes up and down. When it's down, nobody cares that they're driving a gas guzzler, but when it goes up, people flip smooth out and start shopping for econoboxes.

 

[swampratt]

It's crazy to think that 30-40 years ago, the majority of mankind didn't know what their vehicle's mpg even was, and could care less if they did know lol.

I was never in the majority.

I have always checked my MPG since I started driving.
It is a good indicator on how well the engine is working.
If I am down a few MPG it tells me something is wrong or I need to get my foot out of it.

I always wanted the best MPG I could get.
My first vehicle was a motorcycle 400cc Kawasaki LTD 67 MPG and my dad rode it a little easier than I did and would get 76 MPG.
Then came the cars and inline 6 Ford engines is what my first 2 had and 24MPG was the norm.

A car hit me on my motorcycle and i got a little cash after paying the doctor to put my toes back on.
I went to buy a larger motorcycle 1988 Honda GL1500 Goldwing and the salesman told me 24 MPG.

NOPE.
I bought a 1984 Honda V45 Magna used for 1,600.

I have always been about the MPG.
My friends told me I was so tight they could hear me squeak when I walked.

 

[Okie4570]

I was never in the majority.

I have always checked my MPG since I started driving.
It is a good indicator on how well the engine is working.
If I am down a few MPG it tells me something is wrong or I need to get my foot out of it.

I always wanted the best MPG I could get.
My first vehicle was a motorcycle 400cc Kawasaki LTD 67 MPG and my dad rode it a little easier than I did and would get 76 MPG.
Then came the cars and inline 6 Ford engines is what my first 2 had and 24MPG was the norm.

A car hit me on my motorcycle and i got a little cash after paying the doctor to put my toes back on.
I went to buy a larger motorcycle 1988 Honda GL1500 Goldwing and the salesman told me 24 MPG.

NOPE.
I bought a 1984 Honda V45 Magna used for 1,600.

I have always been about the MPG.
My friends told me I was so tight they could hear me squeak when I walked.

When I started driving, it was 3 miles from home to the high school, 9 miles or 35 miles to where I fished/hunted, and didn't do much extra driving around other than that. 12gal tank in my 71' bronco, or a 32 gal tank in the 81' bronco and I'm pretty sure I never check the mpg in either one. Wasn't until I was married and moved to the western side of the state that I even start paying attention to it. From about 300 miles a month to about 2500-3000 miles a month once we moved out here lol.

 

[Okie4570]

It was longer than 40 years. Gas was cheap enough that nobody cared 'til the early '70s when they had to wait in lines for gas, then crappy little poopboxes became all the rage. That's also when you got the EPA and the Feds began mandating mileage requirements.

It moves in cycles as the price of oil goes up and down. When it's down, nobody cares that they're driving a gas guzzler, but when it goes up, people flip smooth out and start shopping for econoboxes.

Yeah it was still less than a dollar from the late 80's(when I started driving) to the early 2000's iirc. I could almost fill up a 32gal tank for $20 all through high school and college. I can remember paying $.71 for diesel in early 2003 here. We went to Colorado for vacation that summer and had to pay $1.20 out there and vowed to never go back lol Farm diesel was only $.40/gal.

 

[CHenry]

I remember my 72 El Camino got 20 mpg, with a 350 and 4 barrel carb. 20 if I drove it right but she was fast and I liked to street race lol. Gas was $0.68 IIRC, that was in 85

 

[SoonerP226]

Yeah it was still less than a dollar from the late 80's(when I started driving) to the early 2000's iirc. I could almost fill up a 32gal tank for $20 all through high school and college. I can remember paying $.71 for diesel in early 2003 here. We went to Colorado for vacation that summer and had to pay $1.20 out there and vowed to never go back lol Farm diesel was only $.40/gal.

It’s not about the cost in absolute dollars, it’s about the relative cost increase. In 1970, the national average for gasoline (all grades) was $0.36/gal, but by 1980, it was $1.25/gal. Combine that rise with the fact that the Americans who had been driving in the ‘70s had also lived through actual gasoline shortages, and you had a bunch of people who cared a heck of a lot about their vehicles’ fuel economy. The mid-‘70s was also the timeframe when the EPA started putting MPG numbers on the Monroney stickers of new cars, so you had increased awareness there, too.

 

[madokie]

if the OP plans on doing plenty of highway driving,and no heavy low speed ,granny gear work ,,then putting a taller gear in the rear axle( 3.08,3.27),would be the cheapest way to go,along with taller tires.., if the OP also wants to keep the option of doing plenty of low speed work and highway ,, he could always add a Gear Vendors OD to the back of trans,, not cheap, 2000$, but they are bullet proof..but if good highway MPG is desired , get another truck ,that gets good MPG as is....modding your truck, engine, trans and rear axle can get time consuming, expensive, and may lead to unreliability....if OK ever goes back to doing vehicle inspections then a truck or any vehicle with a swapped engine may not be legal.and i would NOT modify your existing 5 speed trans,, not worth the $$$$ money..

 

[CHenry]

if the OP plans on doing plenty of highway driving,and no heavy low speed ,granny gear work ,,then putting a taller gear in the rear axle( 3.08,3.27),would be the cheapest way to go,along with taller tires.., if the OP also wants to keep the option of doing plenty of low speed work and highway ,, he could always add a Gear Vendors OD to the back of trans,, not cheap, 2000$, but they are bullet proof..but if good highway MPG is desired , get another truck ,that gets good MPG as is....modding your truck, engine, trans and rear axle can get time consuming, expensive, and may lead to unreliability....if OK ever goes back to doing vehicle inspections then a truck or any vehicle with a swapped engine may not be legal.

My 6 cyl turbo f150 will haul balls and tow more than a 460. its getting an average of 21 mpg highway.

 

[dennishoddy]

My 6 cyl turbo f150 will haul balls and tow more than a 460. its getting an average of 21 mpg highway.

Isn't new engine technology great! Our neighbor back in the day was into 5th wheels with a 460. He couldn't keep up with the diesel guys in the mountains, so he went diesel. 90's era.
The new gassers have torque that exceeds diesels from those days. I have zero issues pulling every mountain pass in the Rocky's at the speed limits.

 

[4play]

You have an option to change 1st gear, if you wanted but it won't change the upper gears as in for cruising speeds. This trans is a ZF S5-42 (wide ratio, 5.72 )The same transmission model number, but called (close ratio 4.65) was used in the diesels and can be swapped. People have been known to swap these transmissions either way depending on their desire.

To lower the RPM across all ranges, like mentioned already, swap the rear gears. I believe the two gear options offered new were 3.55 & 4.10, I assume you have the 4.10. If 4.10 ratio, I would drop to 3.73 if doing heavy wotk, or drop to 3.55 otherwise.

Here's, the approx RPM for 70mph with 3 diff ratios. I assumed the tires are about 31" tall.
@70mph
4.11 = 2414 rpm
3.73 = 2191 rpm
3.55 = 2085 rpm