Well, I have been racking my brain trying to figure out what ratio to put in my truck.

I have the 7700 payload package on my truck so I have a 10.25 sterling rearend and the 8.8 in the front(reverse cut) and I currentl am running a 3.73 ratio with 33x12.50x16.5's.

I figured 4.10's but was concerned that it wouldn't be that noticeable from what I have. The only other option would be 4.56 but that may tach out too high on the freeway.

Truck engine is the 5.4L and I have the 4r100 tranny.

Anyone care to throw some opinions my way? Thanks

 

I would think the 4.10's would be just fine that is what I want to put in my 97 F150 running 33's maybe if you plan on getting some larger tires later you may want to go up to the 4.56's now to save yourself the time and headache of having the same problem later. In fact in my current issue of 4WPW mag a guy wrote in with the same question and they recomended going with the 3.73 to get back to stock performance but if he wants to improve performance to step up to the 4.10's which will as they pu it ( Dramatically improve trail performance accelaration,and towing you might lose a bit of fuel economy though)

Richard D.

https://www.f150online.com/galleries....cfm?gnum=2479

 

You're not going to have a noticeable change with 3.73 vs 4.10. For 4X4 cost, it's a waste IMO. For noticeable changes, change the ratio .50 or more, not .25 or so. Next, I would consider my driving habits based on a good gear calculator. www.ring-pinion.com/calculators.shtml#

 

Thanks guys,
Max, What RPM are you running at 70mph? How do you like the 4.10's in your truck?

 

You're Welcome. It runs about 2300 rpms at 70 mph. My tires are only 29" tall, so it runs similar rpms to what you would have with 4.56s and 33s. I love my 4.10s. It's a very worthwhile modification. I've changed many gears over the years; trust me that you will notice little with a change from 3.73 to 4.10. Neither will tach out too high on the highway. If you drive alot of highway miles, you're problem will be reduced mileage.

 

Thanks again Max,
What kind of milage do you get with those 4.10's?
I do a mix of hwy/city with an average of about 13mpg now.
I agree with you about the noticeable difference from my 3.73 to a 4.10 setup but I am leery of 4.56's without trying them or getting some opinions from people on there setups....I see most guys run the 4.56's with 35's and like the setup but I don't know the milage they get on the highway.
Thanks again for the help

 

I'm averaging about 13 city and 16 highway. I agree that 4.56s are steep for some, especially frequent highway drivers. I wish that the 9.75" and 10.25" rears had the choice of 4.30s like the 8.8" rears. The way to get a "between" gear is accomplished by tire height. I guess what I'm trying to say is that if you're hesitant about 4.56s, then I wouldn't waste money and risk getting a whine to only change .25 or so. Good Luck in whatever you decide.

 

Yea 4.30 gears was what I had planned on till I found out they don't have it for my application. bummer. If I go with the 4.56's can you tell me how much of a whine I would get? Thanks again and I promise I will quit asking so many questions ha ha ha

 

You're more than welcome. There are never too many questions. The lower the ratio (higher the number) the more likely you are to have gear noise. The aftermarket gears that you are seeing at those ratios do not comform to "OE" ultra-critical noise standards. Besides the inherent low ratio gear noise, a whine or a whirl from a poor installation and setup can happen. Improper pinion depth, pinion pre-load, and backlash are often the cause. If you use quality gears and have an experienced installer, then that's about all that you can do.