Hello, I can't seem to find a thread on anyone in a Coyote that has done 3.90 gears. If there is one please post link. But I already purchased a set of 3.90 gears for my Coyote. Current mods are cj set up, e85, full exhaust and tune...I'm currently on stock 3.31 gears in my mt82. How much of a difference would I feel from going to 3.90? I didn't want to go to to steep on 4.10. I mainly do roll racing and maybe occasionally track. Coyote is also not a daily driver. Would you say would I have an advantage in roll racing against other NA coyotes or no? Planning on staying NA.. Doing heads and cams next month. Thanks in advance!
Need help on gear ratio
- Thread starter jkudai13
- Start date
I'm not a huge fan of short gears in the coyote because of how short the transmission gears already are. I feel like with 3.73s I'm already shifting too much (most think 3.73s are perfect for NA).
I wouldn't go any shorter than 3.73s unless you're trying to finish the quarter mile at a specific RPM and have the tire needed to get a good launch.
Unless, of course, you like shifting a lot and hazing any tires that aren't drag radials in the first couple gears.
I wouldn't go any shorter than 3.73s unless you're trying to finish the quarter mile at a specific RPM and have the tire needed to get a good launch.
Unless, of course, you like shifting a lot and hazing any tires that aren't drag radials in the first couple gears.
I would think so... I hear guys switching from 3.31 to 3.73 notice a big difference. with a 3.90, top end wont be as good for roll racing in Mexico but not sure how much of a difference it will make for top end... it will definitely help at the track!
Off topic but what numbers are you pushing with your listed mods?
Off topic but what numbers are you pushing with your listed mods?
^ At the moment it's on the boss intake, with that and the mods I listed I made 422rwhp, I feel like those are low numbers because it pulls really hard up top. I'm having the cj set up installed now along with the 3.90's and rst clutch/aluminum flywheel all at once.
That's awesome man, i hear good things about the cj over boss
So the 3.90's are installed, I drove it from tranny shop to another shop to get other work done it and i noticed a whine in the rear end. It's very minimal around 40mph. It gets really loud around 70-80mph cruising in 5th or 6th. Tranny guy said he reinstalled them 3 times to get rid of whine but he couldn't. Called AM where I got them from and they said its normal, to drive it for 1k miles and it will go away...any idea if this I accurate? That whine would most likely bother me in the long run when cruising.
I'm not 100% sure on the 3.90s, but I know the 3.73s like to whine. Is your car lowered? Pinion angle set correctly?
Still not entirely sure why you put 3.90s in a car that mainly sees roll racing though...
Still not entirely sure why you put 3.90s in a car that mainly sees roll racing though...
Yes it's lowered. And yes pinion is set correctly. How does the the car being lowered make a difference in gears whining?
Lowering it affects pinion angle. Bad pinion angle can create noise.
Mmhmm makes sense...what degree is it suppose to be at? I'm on coilovers so I really don't know much of a drop I have, I'd say roughly 2" drop. So what would I need to adjust pinion to correct specs?
If the gears are noisy, they will always be noisy. It's a bad install. Throw them away and start over with a competent installer. I just swapped my factory 3.73s for 3.31s a couple weeks ago because the 3.73s are annoyingly steep with a manual transmission. My friends and I all use the same guy (and have for the better part of 20 years) to do gears because he sets them up right the first time, every time. They have never whined, even a little bit.
Paul.
Paul.
This shop I used has good rep. Well known and trusted. I've been told since motive makes these gears they will be whining. Which I'm not sure how accurate is that. I've seen people's reviews that have these same gears and don't have noise.
I would of. But Ford doesn't make 3.90s. That's what sucks!
Gear whine is all in the setup, isn't normal and no it wont go away.
I've used Motive 3.90's and I had to redo them 3x myself to get them quiet, I never did get FRPP 3.73's to stop whining so in went the 3.90's.
Not saying your guy didn't redo yours 3x but redoing gears is a total money loser for them since they have to pull the rear apart and start over.
How do you like those 3.31's was thinking of swapping those in place of my 3.73's?
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This. I am pushing 500 RWHP, and love my 3.31s. I never experience traction or wheel hop issues, and I can get off the line fairly quickly after my last set of modifications. Granted, acceleration was sluggish when I first owned the car though.
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