The disadvantages of 4.10 gears

[Shdwdrgn]

Yes, it's true -- there is a down-side to having these gears. Every time it rains I have to baby the throttle because the tires break free so easy! Luckily the problem isn't so bad when I'm in 4WD on snow, but I'm still getting a new set of tires before the weather changes. Sure has made it a lot more responsive in rush-hour traffic though.

So, uh yeah, I would highly recommend that nobody else do this mod... terrible results, just terrible...

[bartonmd]

Have you seen any city of highway mileage loss?

Mike

[Cable810]

I've never had that problem...

[navigator]

Jeff, that just means you need bigger tires!

[Trail X]

My 4.56s are great with my 32s. Never had an issue with them breaking away from pavement when I don't want them to. My tires somewhat suck in the rain anyways though (kinda comes with the M/T territory), but the front understeers more often than the rear oversteers in rain anyways, so its not really related to the gearing.

I did lose a bit of fuel mileage, but I still get 16-17 mpg highway. I probably lost between 0.5 and 1.0 mpg. Thinking larger tires may help me a bit there.

[Shdwdrgn]

Unfortunately I don't think I saw a bit of change in mileage with these gears. Since 90% of my driving is in town or below 55mph, and a good deal of rush-hour traffic, I really thought the lower gears would help me pick up something. I think what really killed my highway mileage was the tires... I could originally push into the 20's, but now it's more like 17-18mpg on the highway. I'm running 265-70-16 Big Foot A/T's -- love the traction, but definitely not recommended if you put on a lot of highway miles. For my typical driving, I generally hit just over 16mpg in the Summer (16.16 and 16.27 on my last two tanks) and in the Winter I swing to both sides of 15 depending on how often I have to use 4WD. These numbers are almost exactly what I was seeing with the 3.42 gears.

Bigger tires have always been a consideration. I plan on getting a front lift made to level out the vehicle when I get some cash (lifting the whole thing isn't an option because I need to keep it in the garage, and my wife has back problems so it's already a bit of a strain for her to get in). Going up to 31.6" with the 265-75-16s would be great, I think those tires really fill in the wheel wells nicely. My only concern is that I would need wheel spacers, and while I do love the wider stance, I am concerned that if the tires stick out from the fenders, whether there will still be enough room to walk around the truck while in the garage. I may just have to take some measurements and try to figure out exactly where the spacers would make the wheels sit.

[Trail X]

As long as you use stock wheels, your tires will likely still be within the body. Mine are.

[Shdwdrgn]

I actually decided to go take actual measurements to see where I'm at, and am a bit surprised by what I found...

My tires calculate to about 10.43" wide, but I don't have calipers to measure the actual size.

The front wheels are inside the fender by 3/8" (averaging the measurement from the front and rear to account for the wheel being slightly turned).

The rear wheels are inside the fender by 1-1/4"

That's quite a difference in stance between the front and rear! I suppose the rear fenders may be wider than the front, but it makes me wonder if this is the reason why the rear wheels always look smaller than the front ones? Unfortunately this also means that even if I found some 1.3" wheel spacers, the rear wheels would be fine but the front wheels would be hanging outside of the fender by an inch.

Now it makes me want to find some 7/8" spacers for the rear wheels, just to even it up. I wonder if it's possible to use a combination of a spacer plus longer lug bolts to make that happen safely? Has anyone measured the actual wheel stance at the front and rear to see if they are the same?

[Trail X]

Measure straight up from the center of both wheels. The body is narrower at the bottom than it is halfway up (or bottom of fender vs top of wheel well). That sounds off to me.

[Shdwdrgn]

I didn't describe myself correctly... When sitting on the ground, the bottom of the tire squishes out some. What I did was take a board straight up and down, about 6 inches left and right of the centerline, laying across the edge of the tires. So at 6" to the left, the edge of the front tire was 1/2" inside the fencer. At 6" to the right, the tire was 1/4" inside the fender... thus an average of 3/8" if the tire had been turned perfectly straight. Hope that makes more sense?

[Trail X]

Seems like a high difference to me too, especially considering it isn't lifted so your panhard should be level. Is it the same on both sides?

[Shdwdrgn]

I didn't measure on both sides, but just eyeballing it I can say there is the same obvious inset at the rear on both sides, so it's nothing as easy as the rear axle being offset.

[v7guy]

The only disadvantage of 4.10s is that they're not 4.56s

[Shdwdrgn]

I can't even imagine 4.56's with anything less than 32" wheels. When I had 3.42s I had the pcm4less tune with a #1 shift firmness, and I made some adjustments of my own from there. After changing over to the 4.10s I took it on the highway and punched it from a light... it broke the tires free through all three gear changes. I have actually dialed the pressure table back to stock now, and the shift speed table is at about 50% of stock. If you give the 4.2 a chance to put the power to the ground, it can really surprise you, and it's not too hard to make it undriveable for daily use. My drive to work includes merging onto one highway, and if the road is even a little damp and I get on the gas too hard now, the rear end will get squirrelly on me. I just have to train myself that the throttle is not simply an on/off switch...

[Moots1288]

I can't even imagine 4.56's with anything less than 32" wheels. When I had 3.42s I had the pcm4less tune with a #1 shift firmness, and I made some adjustments of my own from there. After changing over to the 4.10s I took it on the highway and punched it from a light... it broke the tires free through all three gear changes. I have actually dialed the pressure table back to stock now, and the shift speed table is at about 50% of stock. If you give the 4.2 a chance to put the power to the ground, it can really surprise you, and it's not too hard to make it undriveable for daily use. My drive to work includes merging onto one highway, and if the road is even a little damp and I get on the gas too hard now, the rear end will get squirrelly on me. I just have to train myself that the throttle is not simply an on/off switch...

I can't imagine 4.56s with 32s

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[Trail X]

You're right, I need bigger tires - but not for the aforementioned tire-beaking-loose issue.

[v7guy]

3:42s with 32s makes it a dog, you couldn't spin tires if you tried.

4:10s with 33s are decent, I'm not upset about it, but it's better with 4:56s. I never had traction issues with any of these setups and I've driven them all a fair amount on and offroad. Just gotta use that right pedal appropriately. I like more gear personally.

[navigator]

I'm actually debating staying with 32s when I re-gear. It is something I have to think about a little more.
I can fit a 32 in my standard spare location for daily driving, that is actually pretty nice. The 32s have worked really well everywhere I have been. The two hills I skipped on my recent trips was more due to lacking a locker than needing more tire. I have some time so no rush.

[ARC-]

I think the 4.10s front and rear would be nice with the AWD! 255/55-18 on it now. (Another thread alerted me to my 8.6 rear diff) Is there a part # for the 8.6 4.10 rear and the front diff part #s ? please, thank you

[TBYODA]

You talking the 4.10 ring and pinion gears? Yea www.rockauto.com or some other place that sells them.