Gear swap before long road trip or wait?

[jdhunt0]

I have a Sport with 35s and will be taking a 4000-5000 mile road trip out west in July. I currently have stock gearing. Would I be better off to swap gears now or after the trip? Looking to possibly save a little on fuel.

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[Crawldad]

you probably should stay with the stock gearing until after the road trip.
gearing to a higher number ratio will pretty much lower your mpg's unless you drive slower

 

[zeebo56]

you probably should stay with the stock gearing until after the road trip.
gearing to a higher number ratio will pretty much lower your mpg's unless you drive slower

Unless he's never in 8th on the highway then he could potentially increase mpg by being in 8th on the highway which was the case for me and a lot of other sport owners. 8th if he has an auto

 

[jdhunt0]

I do have the 8 speed and rarely see 8th.

 

[zeebo56]

I do have the 8 speed and rarely see 8th.

Your mpg will likely increase. I had 35s on an auto sport and 4.88s increased my mpg a decent amount. Question is do you care about putting 5k miles of wear on the new gears. I don't think 5k miles would be an issue as long as you break it in before your trip. But some might say do it when you get back. I'm not sure the best way to answer this.

If it were me I would do it and enjoy it. I think it makes it easier on the tranny as well.

 

[fat_head]

I'll bet you'd spend more money on gears than save money on gas.

 

[zeebo56]

I'll bet you'd spend more money on gears than save money on gas.

But he plans on doing gears either way. Why not get enjoyment out of the gears for that long trip and also save some gas money which ultimately counts as money off the gears (maybe $100 or so during that 5000 mile trip). That is kind of how I would look at it.

He can even hit a couple trails during that time and he will appreciate the gears for that for sure.

 

[wibornz]

Do the switch now, put the 500 miles on it and change the diff fluid. I can pull 19+ mpg running 37s with 5.13 gears at 70 mph.

As far as break in goes. If the gears are installed correctly, there is zero to worry about. Break in of gears is kind of a myth in my belief. For instance, Do you think Semi Trucks are driven to break in the gears, or do you think they are hooked up to 160,000 pound trailer and put to work? Or 3/4 ton and one ton trucks, do you think that the construction guys are like hey, can't work my new truck yet? Nope, or how about the mom that buys a new SUV or mini van. Do you think those are put through a break in period or just driving......... Fact is most vehicles never or rarely have their diff fluids changed yet still go 200,000 plus miles on the factory fluid.

I change my diff fluid, because I go through water and mud often. Otherwise, it would be a lot less.

 

[DadJokes]

We’re headed west in July for a big trip like you. I just put 35’s on and would like to see 8th more too. I’d do the swap now but my wife isn’t expecting that expense until Fall when I’ll do some axle shafts up front in addition to gears.

 

[oldcjguy]

Do the switch now, put the 500 miles on it and change the diff fluid. I can pull 19+ mpg running 37s with 5.13 gears at 70 mph.

As far as break in goes. If the gears are installed correctly, there is zero to worry about. Break in of gears is kind of a myth in my belief. For instance, Do you think Semi Trucks are driven to break in the gears, or do you think they are hooked up to 160,000 pound trailer and put to work? Or 3/4 ton and one ton trucks, do you think that the construction guys are like hey, can't work my new truck yet? Nope, or how about the mom that buys a new SUV or mini van. Do you think those are put through a break in period or just driving......... Fact is most vehicles never or rarely have their diff fluids changed yet still go 200,000 plus miles on the factory fluid.

I change my diff fluid, because I go through water and mud often. Otherwise, it would be a lot less.

While I 99% agree with what @wibornz says, I wouldn't say gear break in is a myth. You don't need to be gentle with them, but varying loads and speeds when for the first few hundred miles is good for them. As for semi trucks and work vehicles, they don't really care if the diffs whine or make noise for the life of the gear set. Construction guys using their trucks are doing exactly what the gears need, varying speeds and loads, stop and go from site to site, with and without a load, and multiple cool down and heating cycles. We passenger vehicle drivers are primadonnas We want out vehicles to climb the grand canyon with A/C, 10 speaker stereo, good mileage and be nice and quiet LOL.

If you were doing a long highway trip the day after a gear install I'd say wait, but you're talking about a couple of months from now. You should definitely do the gear swap now and enjoy the difference. Take it off road, drive it to work, pull a small trailer, do whatever you normally do. Change the diff fluid and go on your trip.

 

[av8or]

I say Do the swap ASAP. I’m breaking in gears now, and it’s too early to say for sure, but I think my fuel mileage is going up. Overall the trans just seems happier. I know that sounds weird, but the way it rolls through the gears and gets to eighth so quick and easy now is so much better. And it holds eighth really well now. Much less hunting for the right gear, and much less holding of the wrong one.

 

[wibornz]

While I 99% agree with what @wibornz says, I wouldn't say gear break in is a myth. You don't need to be gentle with them, but varying loads and speeds when for the first few hundred miles is good for them. As for semi trucks and work vehicles, they don't really care if the diffs whine or make noise for the life of the gear set. Construction guys using their trucks are doing exactly what the gears need, varying speeds and loads, stop and go from site to site, with and without a load, and multiple cool down and heating cycles. We passenger vehicle drivers are primadonnas We want out vehicles to climb the grand canyon with A/C, 10 speaker stereo, good mileage and be nice and quiet LOL.

If you were doing a long highway trip the day after a gear install I'd say wait, but you're talking about a couple of months from now. You should definitely do the gear swap now and enjoy the difference. Take it off road, drive it to work, pull a small trailer, do whatever you normally do. Change the diff fluid and go on your trip.

I don't think people in general do a gear swap or buy a new vehicle and then immediately jump on the hwy and drive a couple thousand miles. Yet we know that there are people on this site that have bought a Jeep out of state, flown to the area, picked up their Jeep and then drove across the country with out any negative reputations. The manufacturing processes are so much better than they were even a decade ago.

 

[jdhunt0]

Thanks everyone. Now I just need to decide on 4.56 or 4.88. For my mostly highway I think 4.56 will be fine even if I go to 37s.

 

[wibornz]

Thanks everyone. Now I just need to decide on 4.56 or 4.88. For my mostly highway I think 4.56 will be fine even if I go to 37s.

I have ran 37s for almost 50,000 miles. You will not be happy with 4.56 gears and 37s. You may not be happy with 4.88 gears and 37s if you live in a hilly area or have lots of wind. The trans will still search for gears with 37s. If you plan on 37, go right to 5.13 and never look back.

 

[av8or]

Thanks everyone. Now I just need to decide on 4.56 or 4.88. For my mostly highway I think 4.56 will be fine even if I go to 37s.

For reference I have 5.13 with 37s.

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