4.88’s and 32’s - honest opinions from a shitposter

You are welcome. I appreciate the feedback.

 

All opinions are welcome here. It’s what makes the world go around.

 

Good unbiased write up. I have a slightly modified MT with 265/70R17’s and OTT tune. I have regeared my Jeep twice (3.55-4.10-4.88) and my last frontier (3.69-4.56). I love low gears, and I am planning on 4.88s eventually. I am one of those guys that likes to wind the gears way out and I don’t mind cruising at a higher rpm though, hence why I want to swap. I like where 6th is already and don’t really want to change it but I will sacrifice that for the rest of the boost in performance. I’m tuned as well with OTT but that wasn’t enough of a change for me. With some lighter non load E tires, 4.88s, AND the tune, I think I’ll finally be where I want to be.

Just curious, what gear oil did you end up with? If you didn’t already, something like a thick conventional 85w-140 might just do the trick for the noise. No guarantees, but it’s not exactly gonna break the bank to test it out. I ditched the stock fluid and put Currie gear oil in and mine definitely seemed to quiet up a bit. Just an idea, worth a shot maybe unless you live in extreme cold where that may be too thick a choice. Personally I think the gear oil Toyota uses is a bit thin for a truck. I have no doubt in my mind it’s for mileage/EPA reasons. Although even with me swapping to the heavy stuff I’ve never lost mileage.

 

I totally agree with you it’s mostly all obvious. I guess my reason to share my experience with TW is maybe to help new people, or people who are not mechanically minded, by offering another perspective than the typical “spend more money to make the truck more gooder”. That thought process is rampant in all vehicle forums. Especially in terms of a large investment like gearing, I think there are some notions that need to be dispelled or at least counteracted with a different opinion.

The concept of “Toyota should have shipped these trucks with 5.29s from the factory”, which you hear some version of on TW from time to time, is mostly a fantasy that would be hugely annoying to most owners. I personally would not want anything close to 4.88’s on a stock taco with stock tires.

 

That works as long as you consider stock to be ideal. Some do, some don’t. Personally I have felt just about every vehicle I’ve ever owned would be more enjoyable with lower gears that stock. I plan to stick to the TRD pro tire size but go to 4.88 on the MT.

 

Thanks for sharing you experience. I do run the 85W140 in the rear diff. It helps a lot with the whine. I first ran 75W110 synthetic after draining the break-in oil, but quickly realized it was much louder, so I went back to the same Lucas 85W140 that was used when the gears were installed and it made the gears quieter for sure.

I believe there is a chance that Nitro recommends 85W140 because they know aftermarket gears are noisy and recommending the thicker fluid cuts down on noise complaints after installation.

I have been told that Toyota OEM gears are cut using a different process than aftermarket gears like Yukon, Nitro etc, which is why the aftermarket are louder.

 

Yeah it can help with protection in the heat/towing and can also muffle noise better so I like to use it. My frontier had a leaky axle seal replaced by the dealer (they replace the whole shaft with a new one that comes with a bearing and seal on it) and it was leaking again same day. I threw in the Currie oil and the leak stopped, so that’s also why I use it. I believe it swells the seals a bit.

anyways, bummer it didn’t fully fix the whine but at least it helped.

and yes, I believe the manufacturing process is different as well as the teeth are simply meshing that much more often in a 4.88 application compared to 3.90, so there is reason to expect some noise regardless simply going to a lower ratio.

When I do mine I will buy the diffs prebuilt from ECGS. However, I wish I could specify Revolution gears instead of Nitro. Wonder if they are any better on noise. Revolution has an amazing gear reputation from the Jeep world and everybody that sets them up comments about how they were the cleanest gears they’ve seen come out of a box and the easiest to set up. Basically never see a bad review of them.

 

There has been some speculation here on TW that Nitro and Yukon are made in the same factory and put in different boxes, but I can’t confirm that. This is supposedly why they both behave pretty much the same, with no clear advantage of one over the other. The revolution gears are supposed to be made in their own facility so may be a better or different product.


It is also worth noting that there are many complaints on TW, and even a TSB, for the factory gears whining, so it’s not like Toyota are miracle workers. I just happened to luck out with my truck, which had a mostly silent OEM gear set from the factory.

I will look into this Currie Oil. I’m not familiar with it.

 

Yes I believe Yukon and nitro are from the same place in china. Though I’m not 100%. Revolution are made by Circle K in Korea, no ifs ands or buts. G2, Ten Factory and Alloy USA also ship from there but they cater to Jeeps, not Tacomas. Revolution is a fine product, the bad is they are out of stock all the time lately and nobody like ECGS builds with their parts and ships a turnkey product. So unless I want to buy the parts and have someone install them, I’m pretty much stuck on nitro.

I have seen many complaints of the stock gear whine and I’m sure to some degree it’s real but I think some people are concerned about nothing to some degree. I have never really found a truly quiet truck out there from any brand. My truck makes noise as well but it’s not that bad. Either way, definitely annoying to add on more noise but it is what it is.

the Currie oil is what Currie used on all of their Ford 9’s. Those axles have a very unique gear mesh which needs a good heavy fluid to keep it happy. I don’t know that it would provide any real improvement over the Lucas 85-140, but maybe. Certainly wouldn’t want to get your hopes up on that to be let down.

 

Good points. The whining in my truck ain’t bad. Just present on decel and more than it was before.

 

Non-Or, I was in a bind and bought a Limited before iI realized what all it was missing.

 

Great write up and info!

 

Thank you.

 

I agree.

 

I don't mean to start a debate...
Just my $.02 and maybe food for thought.

The justification of 85W-140 by most end users is the ECGS recommendation and noise abatement.

I understand the ECGS reasoning for 85W-140. Outside of primarily high load use, I don't agree it is applicable to all/most applications.

Hypoid gears rely mostly on boundary and mixed film lubrication; bearings rely mostly on hydrodynamic lubrication. Synthetics excel in boundary film lubrication...

Decel whine is usually pinion bearing; bearings generally like a thinner oil.

 

Thanks for the write up, my favorite one on a gear upgrade so far.

 

Thank you Stocklocker! I'm putting in the same gears with 265/70 17s.

 

I did try the thinner oil, and it was louder, so although your points are likely right, the 85W140 does quiet it down some.

 

I hope the info proves helpful.

 

How many Schrutte Bucks did it set you back?