4.88 or 5.29's

[oly884]

Well, I'm going to re-gear my truck (don't know exactly when) because of the 4WC and the 255's. I know Steve is running 5.29's and I'd like to hear his imput too.

the 4.88's would be nice for the all around useage, driving to and from work, etc. However, with the additional weight of the 4WC it might still be a bit on the doggy side (not style you sicko's) in some cases.

The 5.29's would be nice for exploring (get my low range, even lower than stock) and would be nice for the passes and what not. I don't see anything above 70 mph anymore with the camper so I have a feeling that it would work out with the 5.29's.

Comments, suggestions? (and yes, I'm getting an ARB in the rear (maybe front if the $$$ works out) when I regear)

[pskhaat]

5.29s

Why mess with something you may want to upgrade to later?

[Scott Brady]

With the 5 speed, 5.29's will be a little low but worth it.

The manual has a .80:1 OD and the automatic has a .70:1 OD.

Considering your goals with the truck and the weight you will be hauling around, I would get the 5.29's I have no regrets going with that ratio.

If you like cruising faster than 75 mph on the highways, then you will need to get the 4.88's

[DaveInDenver]

Go with 5.29 and don't look back. The ratio tables probably will indicate 4.88 to retain stock RPMs and that's true. But the tables don't compensate for increased unsprung weight of bigger tires and increased rolling resistance of a larger tire footprint. In the case of a 4 cylinder truck like mine this was definitely non-trivial, maybe less so in a V6. My RPMs are higher than stock, but not hugely (roughly 72MPH = 3000 RPM on 33x9.50 ATs at 35 psi). My mileage, though, did increase and the truck pulls much better from stoplights and climbing in the hills.

There are a couple of reasons not to go with 5.29 in Hilux axles. One is that it's a 7 tooth pinion and 37 tooth ring gear in the 8" third member, which can be a durability issue for really heavy duty use. The 4.88 is a 8/39 configuration and stock (in my case) 4.11 is 10/41. Long term, I dunno. I went with 5.29 just the same, it seems that the aftermarket 4.88 and 5.29 gears are about the same in terms of quality and longevity (which is to say they're OK, but a definite hit compared to stock).

The bottom line is packed you will love the 5.29s and mileage does not take much of a hit. This does depend on your motor to some extent, but an engine isn't going to always use less gas at lower RPMs. An engine could use less gas at 3200 than at 2800 if the torque curve and internal losses balance better there. I think in my case the 22R-E is happier cruising at 3000 RPM than the factory 2500 with the amount of payload I ask it haul around.

[crawler#976]

First off, my opinions on 5.29's and 5.71's are based on several years of hard core rock crawling in a truck that was also a daily driver. You will find other opinions on this that say the opposite is true - and that's fine. Maybe for some folks they work, but I've personally broken way to many, and watched at least a dozen sets grenade on AZ trails. Bear in mind, these are 4.0 to 5.0 on a scale of 1 to 5 trails where the skinny pedal is being depressed to the floor at low, low gear ratios. I'm actually geared pretty high at 109:1 - most of the guys are at 170:1 or better...as low as 1100:1 (Marlin's truck w/ triple t'cases!!!)

I put 45,000+ miles on the rear spooled '87 BPOS before retiring it from daily use. This is definately not "normal" use by any means. The truck is rolling on 35/12.5-15 MT/R's. In those miles, I have broken or burned up 3 sets of rear gears and one set of front gears along with a broken front Detroit Locker. Two rear sets were from breakage while crawlin, one set from improper setup. The front was also due to crawlin - when the Detroit broke it also destroyed the R/P.

IMO, 5.29 and 5.71 pinions are weak and prone to breakage under severe use. The list below is tooth counts for various R/P ratios. These are for the venerable 8", but also apply to the 8.5 non-elocker.

4.11 37-9
4.56 41-9
4.88 39-8
5.29 37-7
5.71 40-7

As the ratio changes the pinion head gets smaller and smaller. One tooth lower makes for a large decrease in pinion size. Subsequently, the smaller pinion generates more heat. I only use high quality full synthetic gear oil in my thirds and gear boxes - both tranny and dual t'cases.

With a 3.4L and 5 speed your way ahead of me on power - 22RE and G56 five speed. I know if I had the 3.4L in the BPOS, I'd be using 4.56's or 4.88's - probably the later.

Perhaps the most critical issue in regearing is proper setup. Find a shop that can give you multiple references from Toy owners. Toy thirds are very, very picky about setup - they will take a ton of abuse IF they are done right. My last spooled thrid went 30,000 miles before it let go on one of the Hammer trails. If your mechanic hasn't done a bunch of Toy thirds, I'd suggest getting them from a reputable shop via the mail. My current rear is from West Coast Diff, and has performed flawlessly. (Now I've done it, I went and put the WHAMMY on myself - I see that that guy Murphy pokin' his head over the hood again)

After install breakin is even more important than the install. Follow the instructions from your installer to avoid voiding your warrenty. My personal method is to use 90W dino juice, drive 20 miles of easy stuff at varied speed, stop and let the diff cool completely. Repeat the procedure. Drive normally (NO TOWING) until you've got 100 miles on the diff. Drain and refill with 90W dino juice. Drive until 500 miles. Drain and add what ever diff juice you like - I prefer a full synthetic 75W-90 from Valvoline. The reason I don't use synthetic on breakin is that it is TOO slick, and won't allow the gears to break in properly.

As far as hard core crawlin goes, I'll never use a Toy axle again. I've spent enough on thirds to have mildly built Dana 60's front and rear. Oh well, live and learn. Even with full width axles, by using reverse offset rims, you can come out within 4" of stock width.

So, to summerize, on a daily driver, I'd stick with the 4.88's for increased strength and longevity. Make damn sure of your setup dude, and run the best gear oil you can afford.

Just to give you the opposite side of the spectrum, take a look at Zuk's page. He says the 5.71's are stronger. I personally disagree!

http://www.gearinstalls.com/

Mark

[Scott Brady]

Considering he is running a 4Wheel Camper and is looking for more overlanding than technical trails, I would recommend the 5.29's

I went with the best gearsets and the best installers (4Wheeler Supply) and the best oils (Mobil 1 synthetic) and have had no issues in 20,000+ miles of hard, over GVWR use. No extreme rock crawling, but plenty of 3+ obstacles.

A 7.5" front diff. is not intended for heavy rock crawling anyways.

Low gears with lockers and a cerebral drivers can keep a 5.29 gearset alive for the life of the truck when used for exploration and light trail use.

[Brian894x4]

One of the best, most compelling articles I've ever seen to debunk what appears to be a myth about the 5.71/5.29 gears is this one.

http://www.gearinstalls.com/410suck.htm

The jist is that the gear contact with the lower ratio is actually more than the higher ratio gears, the ring gears are actually stronger and the most likely reason for the perceived common breakage of these gears is poor quality install. Also makes some REALLY compelling arguments for putting the lower gearing in the diffs instead of the T-case, but that's another topic.

Good read.

As for which ratio to go with, I always recommend the 5.29s for any "older" low powered Toyota with 33s or taller that is carrying a lot of weight. But if you have a 3.4 V-6 it starts to get debatable. You also have to keep in mind that Tacos had much higher gears stock than the older trucks, so even 4.88s with 33s are going to give you higher rpms than you're used too, so 5.29s will really bring you into high rpm territory and knock your speedometer way off. Now, with that said, I don't agree with Toyota's selection for Taco gearing, and still believe that 4.56s should have been used for all 31" tired Tacos, thereby making 4.88 the equvilient ratio for 33s and 5.29s for 35s.

If you had an older truck, a 2.7 4 cylinder or an auto with the higher ratio, then going 5.29s would be a no brainer. The super high overdrive would keep your rpms in check and you'd want to lower ratio to overcome the lack of gear options and super high tranny gears. But with a 5 speed and the more powerful 3.4 V-6, it's different. With my 33s and 5.29s my rpms are about 3000 at a corrected 60 mph. At 70, you'll be pushing close 3500rpm. If that sounds OK to you, then go for it.

It's a tough decision. I'm a super big fan of low diff gearing, but I'm not really sure what I'd do in your case, although I lean towards the 5.29s.

[DaveInDenver]

I agree that anything other than stock 4.10 in a hard core rock crawler is asking for trouble, just too much torque and housing flex. You are doubling or more the drivetrain torque with tires several sizes larger and way heavier on axles that were never designed to see it. I mean comparing a Dana 60 to a 8" Toyota? That guys run Marlin drivetrains and 37" tires on Hilux axles at all is pretty amazing.

Why do I think stock 4.10s are good? If my notes from my 5.29 install are right, the stock 4.10 in a 1991 8" rear diff are 41/10. That I think should hold true of 8" axles after 1982. The 8" axles before 1982 and the 7.5" diffs had 4.11 ratios, which is the 37/9 combo. Aftermarket 4.11 gear sets usually also come 37/9. This is part of the reason why I think stock gears on Toyota 4 cylinders with 225/75R15 tires (this got the über common 4.10 combo) last so long.

[Brian894x4]

Dang it, I just reread the article http://www.gearinstalls.com/410suck.htm that see that removed most of the photos and is in the process of rewriting it. Sorry.

Well, it goes something like this from memory. The number of teeth may be numerially less on 5.71 than 410, but the amount of actual metal contact will either similier or more on the 571. He made compelling arguments that most gear ratio failures are due to poor quality install, while stock 4.10 gears are installed at the factory and are obviously done properly, while ALL 571 installs are done by aftermarket installers, most of which probably don't follow the exact proper proceedure and spec.

What it really comes down too is that the gears themselves are stronger and the pinion contact the same or more, so there's no real evidence to support 571s (and thereby 529s) being weaker than 410s inherently.

He also made a compelling arugument about running 410s in the diff, and super low T-case gearing and how much stress that puts on the drivetrain, verses just running 571s and factory T-case gearing.

Sorry, I really wish his article was still there and complete as he explained it all really well.

[DaveInDenver]

He also made a compelling arugument about running 410s in the diff, and super low T-case gearing and how much stress that puts on the drivetrain, verses just running 571s and factory T-case gearing.

That makes sense, If each component in the drivetrain multiplies torque a little at a time, each is under relatively less increased stress. If you gain 20% in the diffs, that's 20% less you need to gain in the drivetrain to achieve the same amount of increased torque at the wheels.

I think the best approach is to gear the diffs to put the engine at a target RPM with your GVW and tire combination for a given cruising speed. Then gear your 4-low to bring the off highway performance into the range where you want it. This is really the fundamental difference IMHO between recreational rock crawling and recreational expedition. I expect to use 4-high and 2-high often for long periods, be that on pavement, dirt roads or whatever and so high range gearing for that useage is important.

I personally used 50MPH in 4th gear and ~2800 RPM as a goal. That ends up being my most commonly used combo for open dirt road travel. I got lucky that I had a 5 speed and could live with the slower speed 5.29 gears would require on the Interstate, but everyone is different.