Another gearing question
Thread Starter
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Tuned
Joined: Aug 2003
Posts: 363
Likes: 15
From: west central wisconsin
Another gearing question
Have a 86 F-350 2wd dually 6.9l 4spd 235/85/16 tires. Currently runs 2200-2300 at 55mph. Would love to have her run 2200-2300 near 65-68 mph. Basically looking for better fuel mileage. Can someone give me an idea of what gear ratio I need? Also whats the best place to buy the gear set, I'll install them myself. Thanks
Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
Originally Posted by chipper
Have a 86 F-350 2wd dually 6.9l 4spd 235/85/16 tires. Currently runs 2200-2300 at 55mph. Would love to have her run 2200-2300 near 65-68 mph. Basically looking for better fuel mileage. Can someone give me an idea of what gear ratio I need? Also whats the best place to buy the gear set, I'll install them myself. Thanks
I am assuming you got a standard, if your truck is an automatic then the conversion to a ZF5 would be even more costly.
Refer to the attached web page for more details on the ZF5:
http://www.zf.com/na/defaultz.asp
Seb...
Elder User
Joined: Sep 2005
Posts: 641
Likes: 1
From: Delta B.C.
If you look you can find....
I can get my hands on a 1989 F350 2wd 7.3L 5 speed that has only the cab forward left for $500 canadian....
The ZF is by far the best way to go....
I had 3.55 gears and 315/75/R16 tires and was still unhappy with the hwy RPMs....
I can get my hands on a 1989 F350 2wd 7.3L 5 speed that has only the cab forward left for $500 canadian....
The ZF is by far the best way to go....
I had 3.55 gears and 315/75/R16 tires and was still unhappy with the hwy RPMs....
Thread Starter
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Tuned
Joined: Aug 2003
Posts: 363
Likes: 15
From: west central wisconsin
Never took the time to look at what gears are already in the truck. Quess I figured to replace them no matter what they are. I'm a little concerned about power loss but I do my heavy pulling with my Freightliner, Cat diesel. My biggest complaint is screaming around town at 2300 rpm only going 55mph and the 10 mpg. First gear is almost worthless, I'm taking off in second 90% of the time. I've thought about the 5spd but $250 for a set of gears sounds like the way to go. But what ratio???
Elder User
Joined: Feb 2007
Posts: 549
Likes: 1
From: Mississippi
it would be my guess that you've got 510's in the rear end if you're running 55mph at 2200 rpm. i've got 410's in my '90 f-250 and am running 65 at 2150 to 2200 rpm. if that's the case that you've got bigger than 410's, i'd try to get some 355's. personally, i'd like the big gears and just go with taller tires, but don't think that's an option on dually...... but that's just a thought.
speedrdr
speedrdr
