gears
 

so im thinking about going in and re gearing my truck. right now its got the stock 3.73 spinning 37" tires and my fuel economy sucks. from what ive heard talking to people if i went to a 4.10 then it would be like running the stock tires on the stock gears

so i wanted to get yalls opinions bc im gettin 16 mpg and hae heard that getting the gears back to normal (with my tuning) i could get up into the high teens or low 20s

any info on this would be amazing.

thanks

jeremy

I loved the combo of 3.73's and 37's... Ran that way for about 160k. Now I have 4.30's and 37's and IMHO there too tall a gear. Sure its fun around town, but out on the Interstate I run above 2000RPM's above 65 or so.

I know the fuel economy probably isn't great, but you're running 37" tires...

I'd stick with the 3.73's too.

you could bump it to a 3.90? if you really wanted, if you do much highway i wouldn't go too much over that, if its just around town i think 4.30s would be pretty sweet

Fixed it for ya ;)


OP....The "new" ones--2011, maybe 2010 even--are running 3.31 ratio with the diesel/Torqshift combo.

3.73 is a good gear. 4.10-4.30 gets to be too much with the older truck's transmission ratios.

16mpg out of a 7.3 extra cab with 37's isn't too bad at all actually. Those trucks aren't economy queens.

I talked with Dale @ Tymar and we were running some ratio configurations...

I am running a 35" tire w/3.73's which calculates to running 3.31 gears, which pulling a 35' 5'er isn't ideal...

I would have to go to a 4.10 gear w/35" tires which calculates out to like a 3.77 or something like that.

Just my 2 cents!

Trust me... I never had any issues towing up to and over 27k GVW on a F-250 with 37's and 3.73's...

So do you mostly tow with O/D locked out?

What speed do you to at?

What are your rpm's at, at cruising speed?:humm:

Well I dont have the 3.73's anymore... I thought I would be smart and when I blew up the rear end step up... Wish I had not.

Most of my towing was done above 65 mph...

Here is from about 15mph to about 50mph with the 3.73's and about 25k in tow...


And another up in the mountians following Chelseas X with a trailer in tow... Dont laugh at the music, just what was on the radio...LOL

So do you tow with O/D locked out?

given all this i think im gunna stick with the 3.73s its got. my mon-fri driving is mostly in town with maybe 5 miles at 55-70...but on weekend when i go home (college student) i do a 100 mile one way trip at 70+ the entire time.

as for 16mpg spinning 37s im ok with it but i just want to get some better numbers if i can. im sick of having to fill up once a week and watch $80-$100 fly out of my wallet like its nothing

Nope... No need to lock out OD...

Only time I will lock it out is if its hunting for gears.

I just towed my trailer to Kalispell over the weekend, and I couldn't run in O/D all the time, the egt's would climb so fast when the truck started to climb a rise and the tranny didn't kick down soon enough. So I was constantly manually locking out the O/D.

I'm towing 12,000 lbs running 35's w/3.73's, your towing 25k running 37's w/3.73's (used to be 3.73's).

My truck wouldn't pull 65-70 mph in O/D without the egt's hitting 1200-1250, the road is not flat but it wasn't like I was climbing huge passes.

Have you checked for boost leaks and drive pressure leaks?

There is no reason you should be having EGT issues at those weighs and power levels.

Chelseas Excursion is on 37's and 3.73's and I pulled a F-250 like mine on my trailer without issues from Bend to Portland... Just set the cruise and go.

Haven't checked for drive pressures leaks...I do have a an up-pipe leak which I am going to address this weekend.

Even the smallest drive pressure leak will cause high egt's.