Rear end gear change help
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Rear end gear change help
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I just bought my first diesel truck and am loving it. Problem is, it is a 1986 F250 with the 6.9L non-turbo and a T19 4spd manual tranny. The rear end is a single axle with what I believe 4.10 gears in it. At 60 MPH I'm running about 2500rpm +- 100rpm. My question is would changing the 4.10 gears out for say 3.55 or 3.73 gears help improve hwy cruising speed. I mostly travel 60-65mph and really don't do any hauling at all. Oh forgot to mention, the truck is a 2wd extended cab long box. Thanks for any information.
I just bought my first diesel truck and am loving it. Problem is, it is a 1986 F250 with the 6.9L non-turbo and a T19 4spd manual tranny. The rear end is a single axle with what I believe 4.10 gears in it. At 60 MPH I'm running about 2500rpm +- 100rpm. My question is would changing the 4.10 gears out for say 3.55 or 3.73 gears help improve hwy cruising speed. I mostly travel 60-65mph and really don't do any hauling at all. Oh forgot to mention, the truck is a 2wd extended cab long box. Thanks for any information.
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From: Virginia
Put 3.08 gears in it. Find out what type rear you have. I think someone said if it has the fill plug on the drivers side of the rear, it's a Ford rearend. If it has the fill plug in the back of the rear, it's a Dana.
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From: Virginia
I think someone on here said Ford doesn't make 3.08 gears for that rear, but the aftermarket does. If you put those in, you may be able to approach 20 mpg. That would be perfect for a truck that rarely carries a load. I am not sure how low 1st gear is on a t19 tranny, but it may be low enough that you could still get a load moving if you wanted to.
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From: KY
Originally Posted by Bruiser_86
Does anyone know a good place to order some 3.08 gears? Having trouble locating 3.08 gears, can find lots of 3.55 gears.
I don't know for sure myself if you can put 3.08's in a Sterling 10.25 that had 4.10's in it. You can't with a Dana 60. You have to use a Dana 61 housing for a 3.07 gear and that isn't uncommon on rearends.
THere is a big physical difference between a 410 and a 308.
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Joined: Nov 2003
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From: Duluth, Mn.
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From: Campbell River, B.C.
Ford never offered a 3.08 ratio for that differential, but there are aftermarket sources.
The brand I used was Motive Gear, they were the best peice I could find so thats one more potential source for you. I have racked up over 40 000 miles so far with no problems, was hardly even a breakin to speak of.
Your best bet is to shop around on the web to find the best deals.
The neat thing abould going all the way to 3.08 gears, is you will gain the ability to drop a gear when your at sub freeway speeds, like 40-50 mph, for me, it meant that there was no performance change after the swap, except for the higher top speed
.
Unless you plan on towing more than 10 000lbs consistently, you will not regret doing the swap.
The brand I used was Motive Gear, they were the best peice I could find so thats one more potential source for you. I have racked up over 40 000 miles so far with no problems, was hardly even a breakin to speak of.
Your best bet is to shop around on the web to find the best deals.
The neat thing abould going all the way to 3.08 gears, is you will gain the ability to drop a gear when your at sub freeway speeds, like 40-50 mph, for me, it meant that there was no performance change after the swap, except for the higher top speed
.Unless you plan on towing more than 10 000lbs consistently, you will not regret doing the swap.
Last edited by David85; Aug 9, 2007 at 11:01 AM.
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