Noise from 4.88s? (1 Viewer)

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I went to a local shop that works on differentials and asked what the downside to re-gearing using the Nitro kit might be. The mechanic said:

1. Limited top speed and heavy fuel consumption over 60 mph.

2. There can sometimes be a whiny noise.

Anyone who's done the re-gearing experience these?
 
No to both. That mechanic probably doesn’t know we have a .59:1 (2008-2015) final drive.

My 4.88s are dead quite at 100 mph and yield me better MPG than the stock 3.90.

If I had a 2016+, I would consider 4.30 as the 8 speed doesn’t have as low of a final overdrive as the 6 speed at .67:1. So a 2008-2015 with 4.88s yield the same RPMs at 75 mph as a 2016+ with 4.30s. A 2016+ with 4.88s will rev even higher than the 2008-2015s, and could be a good option for heavily modified 200s that tow serious trailers.
 
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Same here - my gears are like OEM in noise.
 
I went to a local shop that works on differentials and asked what the downside to re-gearing using the Nitro kit might be. The mechanic said:

1. Limited top speed and heavy fuel consumption over 60 mph.

2. There can sometimes be a whiny noise.

Anyone who's done the re-gearing experience these?

If his gears swaps make noise post-swap??? Find another shop!!!

They should be just as quiet as stock gears, or something is wrong.
 
Completely quiet here and I haven't noticed any change to gas mileage.
 
They should be just as quiet as stock gears, or something is wrong.
I don't have mine yet, but I've been in three re-geared rigs and heard nothing unusual.
 
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Sweet!!

Thanks fellas - that settles it.
 
No issues at all. Go for it
 
Even then, find a different shop. Their gear guy doesn’t know what he’s talking about.

Strongly consider sending your thirds to zuk.. few people have as much experience setting up toyota diffs.
 
Can anyone recommend a shop in SoCal?
 
Ugh, one of the above just told me that aftermarket gears will not last nearly as long as factory. It makes sense, but what a downer.
 
Ugh, one of the above just told me that aftermarket gears will not last nearly as long as factory. It makes sense, but what a downer.

Well, that isn't exactly untrue. I guess that depends on the definition of nearly :D Toyota metallurgy, design and manufacturing is pretty tough to reproduce and in fact many gear companies have not over the years. Many gear guys have zero qualm installing a used OE R&P with 200k FWIW.
 
The 4.88s would have the engine turning 25% more RPM at the same speed and transmission gear. I'd be surprised if that didn't consume more fuel, but I don't have 4.88s, and haven't actually tested it.... :)

At 60 MPH the 4.88s in 6th gear (on a 6-speed) would have the engine at almost exactly the same RPM as 5th gear on the stock 3.91s.

RPM at 60 MPH.jpg
 
The 4.88s would have the engine turning 25% more RPM at the same speed and transmission gear. I'd be surprised if that didn't consume more fuel, but I don't have 4.88s, and haven't actually tested it.... :)

At 60 MPH the 4.88s in 6th gear (on a 6-speed) would have the engine at almost exactly the same RPM as 5th gear on the stock 3.91s.

View attachment 1674605
Remember that if you need to regear, you are most likely jumping from 6th to 5th (2008-2015) a lot. That's why you re gear, because constant hunting of gears kills MPG and longevity. Which is why guys see no loss or a slight benefit in MPG. But that guys are not stockers with street tires, as there isn't a need to re gear.

@5ForFighting, Kurt couldn't be more correct (like always) on that it is hard to match toyota's gears, but I've seen Nitro gears with over 250K that are still perfect. If you are really worried, have them cryo'd like I do to last even longer. So while Toyota's will technical last longer, Nitro's will still last just as long enough for you to never think about them again. But like mentioned earlier, if you are jumping between the two overdrives constantly when on the highway, or worst, driving with the torque converter unlocked all day, you are already causing some pretty excessive wear. Then having aftermarket gears makes a lot more sense overall, longevity wise.
 
My reason for regearing is to help with towing. I have larger tires but have not really experienced gear hunting other than when towing in the mountains. I have, however, noticed a pretty big dip in fuel economy (down to 11mpg), and sluggishness around town. Clicking “ect pwr” helps with the latter.
 
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Remember that if you need to regear, you are most likely jumping from 6th to 5th (2008-2015) a lot. That's why you re gear, because constant hunting of gears kills MPG and longevity. Which is why guys see no loss or a slight benefit in MPG. But that guys are not stockers with street tires, as there isn't a need to re gear.

@5ForFighting, Kurt couldn't be more correct (like always) on that it is hard to match toyota's gears, but I've seen Nitro gears with over 250K that are still perfect. If you are really worried, have them cryo'd like I do to last even longer. So while Toyota's will technical last longer, Nitro's will still last just as long enough for you to never think about them again. But like mentioned earlier, if you are jumping between the two overdrives constantly when on the highway, or worst, driving with the torque converter unlocked all day, you are already causing some pretty excessive wear. Then having aftermarket gears makes a lot more sense overall, longevity wise.
How much was it to cryo your gears?
 
You're definitely in the grey zone. Not modified enough to need 4.88 all the time, but if you tow enough, then it starts to matter more. I would recommend just driving around with the transmission limited to 5th gear (S5) that is exactly what 4.88s produce. I essentially moves every gear, down one. If you are happy when towing and not towing limiting to 5th gear, the decision is easy, do 4.88s. If you don't like it when not towing, then don't re gear, and when you do tow, just know you always have to shift to S5.

@Roy Park, just pulled up my receipt from 300 below. It was $136.50 to cryo front and rear rings and pinions and all six bearings. Then $50 more to ship it back to East Coast Gear Supply where they built the 3rds.
 
I'll try S5 for a tank or two...I guess if I don't like it I'll have Nitro Gears for sale...grrr
 

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