You and me both otherwise this is going to get expensive and fast.

 

If those 4.88s don't work out I'll probably buy them from you, been needing to break open my diffs to stuff some extra goodies in there anyways. Glad your progress is....progressing

 

Roger that, your not running 315's and 4.10's are you? (IF SO YOU ARE A CRAZY MAN, whats your mpg like out of sick curiosity?)


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Looking forward to the results.

 

Haha that I am, I'm in a city with a max elevation change of 100 feet, and that's literally only on one road leading out. I get a steady 13-14 around town, 14-15 freeway. Its a lot better than you'd think but of course 4.88s would be ideal, just have spent my g's elsewhere lately

 

i really hope this comes back that he likes 4.88s. after Scotty's posting on 5.29 i might have to sell my 3 month old 4.88s and get the good stuff

 

Ok so 220 miles on the new gears and so far so good. Though while totally unrelated my T-case is hemorrhaging oil gear oil (this goes back a problem I though was fixed). Tough to say how the gear did as every time I hit 78+ mph a drive-line vibration that didn't feel good would come on. I parked at home to come out minutes later to a puddle (spilled pint size) of gear oil. Sheet I thought grumble grumble I got to get this figured out. Back to the gears, the speed up speed down in traffic was effortless the hill climbing (overpasses) was better and my MPG may be doing well. I will know better later down the road. The rpm's are about 100-200 rpm's higher at each speed which help in the acceleration and power areas. Headed to my leaking t-case thread now.

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The difference between 4.88s and 5.29s is only 9%.

So, at 3000 rpms with the 5.29s, the 4.88s are only 270rpms lower. I usually cruise mine on the fwy at 78mph. That puts me at 2900 rpms via the GPS. 4.88s will be 2640rpms. Still mine is lower than a manual tranny, and have been averaging 19mpg on the hwy. Average with mixed use is 17mpg.

 

i understand that highway performance would be similar between the two gears. but what about in lower gears? I would assume(please correct me, there is a good chance im wrong) that the 9% would make a larger impact on the lower gears, providing more torque at lower speeds but performing similarly on the highway due to the A340Fs crazy overdrive?

 

GEAR RPM
4.56
50mph 1700
60 2050
70 2350
80 2750
83 2800

4.88
50 1800
60 2150
70 2500
80 2900
83 3000

The power between the two is noticeable and the low end torque has increased.

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I want 4.88s now!!!

 

You'll never notice the difference for the most part.

 

Keep in mind folks I'm going for slightly better economy and power. I got a great deal on parts and labor so while my cheap experiment is my own it's likey you will spend more. Though if your jumping from the stock 4.10's stay tuned as you might be impressed. I just feel the 5.29 will be too much of a jump. Here in FL there is no coasting and the throttle is always down.

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Nearing the end of the gear break in period and so far reasonably satisfied with the gearing. I had to fix the t-case leak which led me to remove the entire budbuild skid plate assembly (why not just the rear pan I know not) and then ran out of time before I could re-install it. It is well known (to me anyway) the skid plates help with the overall aerodynamics and I lost some considerable MPG's on this tank (or sheety gas). On the way from S. FL to Central FL my 1/4 tank was 60 miles and the 1/2 tank was 140, while this is not fair to use as a comparison without the front skid at least I will have to get back to you on regular mileage.


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I don't think losing your skids would hinder your MPG's much aerodynamics wise. Compared to losing all that weight, you should see better MPG's. I know those things aren't light.

 

I know everyone will say I'm crazy but every time I run w/o them I lose them the tank suffers. I was under the less weight better mpg but noooo way.

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I ran 4.88:1 with 33" BFG MTs or ATs for years on my '98 Tacoma 6 cyl 5 spd. I got about 19 mpg in CO at around 7,000'. It was a great combo for both on and off road and I would certainly do it again.

Note: Last year I downsized my tires to 31" siped Bridgestone Dueler Revo ATs. I did it for a tread that handles snow and ice better, and the difference has been significant. They've been remarkably good off-road too. Sometimes I miss the tire size, and 4.88:1 is a bit low for the highway now, but I could hardly be happier with the tires.

 

Ok while it would appear a crap tank of gas accounted for the lowered economy (likely higher than normal ethanol blend). My recent trip to pick up a new trailer resulted in this, 1st tank 16.45, 2nd tank 17.8, 3rd tank 18.6, 4th tank 18.7, 5th tank 16.1. The 1st and last tank were in FL (corporate ethanol conspiracy) and I filled up on the 1/2 or 3/4 tank marks.

The gearing helped sooo much in the hills (GA)(N. FL) that I was sold on them for primary running gears. The ability to hold 70 while climbing was an added benefit. The cruise would jump to 3.4-4K on occasion but could be stopped with one click down of the cruise control (CC) before it got to that point. But once back to FL and the million mile an hour head wind the mpg's dropped. I ran 70-78 all the way up and 65-75 all the way back, the mpg's were consistent and I'm pleased. A low weight alternative for the Front Bud built would be nice (street sign (I've been a sign contractor no signs were hurt in the making of this post)or similar light AL).

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So here is another thread revival. I'm looking at getting an ARB locker and wondering about throwing in gears while the diff is opened up anyway. I have 4.10's and 285's right now, and do long highway drives quite often between Bozeman and Seattle quite often, and lots of snow driving. With lots of highway driving, is a lower gear ratio really worth it? Will it improve fuel economy for those trips? My mind still hasnt quite wrapped itself around gearing all too much. Higher RPM's in my mind mean more gas being consumed...

 

Nope, its an open throttle that consumes fuel. You can have high rpms and a mostly closed throttle or low rpms and a wide open throttle. Its all about the skinny pedal.