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The 1.1 underdrive on the 4.30 works out to about the equivalent of a 4.73
I am running 255/85/16 KM3(love them BTW) so actual 33's whereas 285/75/16 always end up about 32.5-32.7...and GPS consistently shows me 88mph when the speedo shows 80....so a 10% underdrive should take me right back to stock; 80mph speedo = 80 mph reality....so I cant see that as being anything but a perfect combo. For 285/75/16 or similar it would only be a tiny bit off stock gearing/rpm's
Update: Had trouble finding someone to do the Transfer case underdrive, so bought some NIB Nitro 4.88's for a Mud member. Now for the review....I have about 1200 miles on my 99 since putting in the Nitro 4.88's....some pulling offroad trailer, some just loaded vehicle, on and off road. I love every single thing about the change! Peppier in town. Far less downshifts on the highway, better hill climbing, transmission seems happier/less confused. No regrets at all. Do the math and you'll see that between 33inch tires and 4.88's my rpms are only up about 5%(using GPS for speed) over stock...that silky V8 doesn't even notice. If you have a 4 speed and 33's or larger; JUST DO IT
Not that I can hear...but my wife says my hearing is going...ha. More importantly she didn't seem to hear any either
I have never heard any with the 4.88s. The gear whine that was being referenced above was referring to the transfer case gear. The 4.88s replace the gears in the diffs.
I have a 2001 Land Cruiser running 295/75 R16 BFG KO2 tires (which should be a 33" tire) on stock rims, and maybe a 3" lift? She has 240k miles, and is carrying a heavy load most of the time: Rear BIO bumper with two swingouts (Spare tire and HI-Lift on one side, 3-can carrier on the other), Front DJM Bumper with Winch, custom sliders, Full Roof Rack with RTT, Foxwing Awning, 4Gal Road Shower, and River Quiver 4-Rod Carrier ). PLus, inside, there is a full TrexBoxx drawer system in the rear. And sometimes I pull a trailer with two or three motorcycles. She is an overlander, not a daily driver, but gets used for trips over 100 miles where the electric car does not have the range.
My last trip up the grade from Bishop to Mammoth Lakes (with trailer), I was doing 40 to 45 mph max. A recent trip to Colorado (no trailer) and the rig could only do 50 or 55 on most of the passes on I-70, and on the steeper passes on other highways I was so slow I was holding up the flow of traffic. On the flats, I usually keep the speed at a true 75 MPH or less.
I'm thinking my best option to improve this performance is to move from stock 4.30 to 4.88 gears.
A few questions:
1) Any other thoughts to improve this performance? Maybe there is an engine issue I might be overlooking?
2) Should I do lockers at the same time? (Not much of a rock crawler, unless you tell me there is good fishing at the end of the trail)
3) Can anyone recommend a reputable shop for this kind of work in the Los Angeles Area? All I know of is RPM near Pasadena (far away) and Dirty Parts (close but pricey).
Thanks!
My last trip up the grade from Bishop to Mammoth Lakes (with trailer), I was doing 40 to 45 mph max. A recent trip to Colorado (no trailer) and the rig could only do 50 or 55 on most of the passes on I-70, and on the steeper passes on other highways I was so slow I was holding up the flow of traffic. On the flats, I usually keep the speed at a true 75 MPH or less.
I'm thinking my best option to improve this performance is to move from stock 4.30 to 4.88 gears.
A few questions:
1) Any other thoughts to improve this performance? Maybe there is an engine issue I might be overlooking?
2) Should I do lockers at the same time? (Not much of a rock crawler, unless you tell me there is good fishing at the end of the trail)
3) Can anyone recommend a reputable shop for this kind of work in the Los Angeles Area? All I know of is RPM near Pasadena (far away) and Dirty Parts (close but pricey).
Thanks!
You will have high RPMs at highway speeds with a 4 speed, 33s, and 4.88s
Higher, yes.
If my quick calculations are correct, aren't we talking about +200RPM, over a completely stock vehicle, on 31" tires, at 75MPH (and +400RPM over a stock vehicle on 33" tires at 75MPH)
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LCMoneyPit
SILVER Star
I am about 26mph per 1000rpm in OD with 34" tires and 4.88s. It starts to get interesting in Wyo with the 80 MPH speed limit.
I will add that the 4.88s and 33s will make 1st gear much better when in low range off road.
I will add that the 4.88s and 33s will make 1st gear much better when in low range off road.
LCMoneyPit
SILVER Star
Even when my 06 LX470 was completely stock, it wasn't my favorite vehicle for the 80MPH sections of I-10 or 85MPH tollways in Texas
1. If your engine is in reasonable tune/maintained, no CE lights, etc...its likely not the engine. The tranny is just a bit out of sorts with 33's and up. I have done the switch to 4.88(see my post #46 from last year, above) and it is one of my very favorite mods. Would do it again 100%. People love to blurt out the myth of "too high rpms on the highway" but don't listen. *jLB does a good job showing the numbers for your rig in his post #53. If you are on 33's now, then your rpms are about 160 lower than stock at 75mph, if you go to 4.88 gears with your 33's you'll be about 160 above stock at 75(about 200rpms above stock at 80). Your 4.7 couldn't care less about the extra 200rpms, your tranny will hold gears better and the rig will feel like it runs better in EVERY situation. I even get better gas mileage, and I've tested it a dozen times using GPS, the same as I did before the swap last year. Also as a bonus, you are getting a lower Low Range in the process. I promise you won't regret the change to 4.88.
2. I would definitely put a rear locker in while you are doing this...works really well with the your ATRAC handling the front.
3. Can't help you with a shop in LA...live in Utah.
I did the 4.88 swap a little over a year ago and can give you lots of feedback/answer questions. PM me if you want
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Even when my 06 LX470 was completely stock, it wasn't my favorite vehicle for the 80MPH sections of I-10 or 85MPH tollways in Texas
I think that I just thought that it was the 4.88s that was making my truck less great to drive at speed on the highway. Turns out a it is just the LC that ain't so great to drive at 90! In my defense, I have never driven a stock 100 series.
I should have added this above, but if the poster is working in a budget, I would toss the transfer case under drive gears into serious consideration. They should be much less expensive out the door, but won't offer the benefits off road in low range that the 4.88s would. Or that an aftermarket rear locker would. I rarely need my rear locker and I almost never need the front locker. I am doing pretty hard trails too.
Sumo Gear Land Cruiser Transfer Case 10% Underdrive Gear Set - Fits 8x/10x Series Full Time 4wd Models
Low Range Gear Reduction Sets for Toyota Land Cruiser Applications
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