Tell me about re-gearing my 5th gen

[Jetboy]

How was the setup process fir the front diff?

Front diff is a PITA without the pinion depth measuring tools. You definitely need to plan on making setup bearings. You'll put the pinion in and out half a dozen times at least if you don't use a pinion depth measuring tool. And every time you check the pattern you'll have to assemble the clamshell, test the pattern, then re-split it and pull it all apart. I'd plan on 5-8 hours of work to do it the old fashion way of paint markings - meaning time to set up the diff, not including removal and install. If you're keeping the OEM carrier - it's a bit easier as you don't also have to adjust shims on the side bearings for pre-load. You may have to adjust them for backlash once you get a proper pinion depth set, but that's not quite as bad as if you are also swapping in an ARB at the same time.

Nothing is particularly technically difficult. It's just time consuming due to all the steps. FWIW - you don't need a specialty pinion bearing removal tool. A high quality bearing separator and a shop press works just fine for removing the big pinion bearing. But you really should buy new pinion bearings and use the old ones as setup bearings. You don't need them. They'll be just fine to re-use, but it'll save a ton of time not having to press them on and off each time. I'd re-use the carrier bearings. No reason to even remove them if you're not changing over to a locker. Even if you are - they're easy to remove and shouldn't have much wear on them, so I'd reuse them.

I'm not really even sure how you'd mount a pinion depth tool in a clamshell, but I'd rent one if you can. It'll save a ton of frustration. I wish I had. The stock pinion will have a depth measurement on the pinion head (at least mine did), so you'll have to do the math from the stock one to the new one and then use the depth tool and measurements of the pinions to reach a final shim value, but that will save a bunch of guessing and narrowing in on the final shim value.

As you probably know, you'll also need a horizontal dial indicator. You can use the horizontal dial indictor for both diffs, so if you don't already have a vertical style one, you only need to buy one dial indicator. But it should be a horizontal one.

As a comparison the rear diff took me about 1-2 hrs to swap gears and get it dialed in. Clamshells are just a huge PITA because of how much work it takes to adjust pinion depth and then to check it each time.

 

[elnip]

I didn't notice any loss of power when switching to 285/70r17s, but a slight MPG drop. Most people don't recommend regearing unless you go with 34s or higher. Adding a Pedal Commander or similar item, will make your truck's throttle response better, which may negate the feeling of power loss and is a lot cheaper.

Not necessarily, when I went from 275 to 285's I had to keep it in 4th just so the trans would not shift 4-5 constantly. Especially towing, very annoying.
Initially was against re-gear but eventually took the plunge to 4.56. Wow!
What a difference. My mileage in town went up 3 mpg and towing is up
2mpg. NO more trans hunting. If anyone is on the edge of yes or no, do it!
You won't be disappointed afterword.

 

[alphabeast]

Front diff is a PITA without the pinion depth measuring tools. You definitely need to plan on making setup bearings. You'll put the pinion in and out half a dozen times at least if you don't use a pinion depth measuring tool. And every time you check the pattern you'll have to assemble the clamshell, test the pattern, then re-split it and pull it all apart. I'd plan on 5-8 hours of work to do it the old fashion way of paint markings - meaning time to set up the diff, not including removal and install. If you're keeping the OEM carrier - it's a bit easier as you don't also have to adjust shims on the side bearings for pre-load. You may have to adjust them for backlash once you get a proper pinion depth set, but that's not quite as bad as if you are also swapping in an ARB at the same time.

Nothing is particularly technically difficult. It's just time consuming due to all the steps. FWIW - you don't need a specialty pinion bearing removal tool. A high quality bearing separator and a shop press works just fine for removing the big pinion bearing. But you really should buy new pinion bearings and use the old ones as setup bearings. You don't need them. They'll be just fine to re-use, but it'll save a ton of time not having to press them on and off each time. I'd re-use the carrier bearings. No reason to even remove them if you're not changing over to a locker. Even if you are - they're easy to remove and shouldn't have much wear on them, so I'd reuse them.

I'm not really even sure how you'd mount a pinion depth tool in a clamshell, but I'd rent one if you can. It'll save a ton of frustration. I wish I had. The stock pinion will have a depth measurement on the pinion head (at least mine did), so you'll have to do the math from the stock one to the new one and then use the depth tool and measurements of the pinions to reach a final shim value, but that will save a bunch of guessing and narrowing in on the final shim value.

As you probably know, you'll also need a horizontal dial indicator. You can use the horizontal dial indictor for both diffs, so if you don't already have a vertical style one, you only need to buy one dial indicator. But it should be a horizontal one.

As a comparison the rear diff took me about 1-2 hrs to swap gears and get it dialed in. Clamshells are just a huge PITA because of how much work it takes to adjust pinion depth and then to check it each time.

I just received my 4.56 gears from Nitro. How much can I pay you to drive up here to Boise and install then? Joking of course. I am just going to make the road trip to Nitro and have then do the installation. It's expensive, but going to be necessary since I am running 35's and will be towing a small teardrop trailer in the near future.

 

[AMLOR]

4.88 in January

The install for Yukon 4.88's is on for early January.
Running a 19 Pro with about 500 pounds of weight added so far, with about another 100 (plus a rear bumper eventually) coming.
Also making the switch up to 33's (285/70/17) as soon as the stockers go bald.

The real reason for the 4.88's over the 4.56 is we will be pulling a camper with a GVW of about 2400 lbs over long distances.

In addition, if I did the math correctly, the difference between a 4.56 and a 4.88 is only about 6.55%. Running 2500 rpm in 5th with a 4.56 is equal to a 4.88 running 2664 rpm at the same road speed...164 rpm difference...that is within my comfort zone; and with the trailer, I will take all torque multiplication I can get.
Better crawl ratio too!

 

[delloro]

The install for Yukon 4.88's is on for early January.
Running a 19 Pro with about 500 pounds of weight added so far, with about another 100 (plus a rear bumper eventually) coming.
Also making the switch up to 33's (285/70/17) as soon as the stockers go bald.

The real reason for the 4.88's over the 4.56 is we will be pulling a camper with a GVW of about 2400 lbs over long distances.

In addition, if I did the math correctly, the difference between a 4.56 and a 4.88 is only about 6.55%. Running 2500 rpm in 5th with a 4.56 is equal to a 4.88 running 2664 rpm at the same road speed...164 rpm difference...that is within my comfort zone; and with the trailer, I will take all torque multiplication I can get.
Better crawl ratio too!

7%.

4.88 gears will give you 30% higher RPM at a given speed than 3.73 gears. As I recall, I am turning about 2100 - 2200 rpm at 80 mph.

2200 RPM with 3.73 = 2878 with 4.88

2200 RPM with 3.73 = 2690 with 4.56

2900 is more than I like, but maybe not everybody drives at 80 mph.

 

[Jetboy]

The deal breaker for me was that even with 4.56 diffs I still could not stay in 5th gear pulling my trailer. And I could hold 4th gear with 3.73 diffs. So my towing experience got worse, not better. I do tend to tow at 75mph when I can, so that might be part of the issue. I could slow down? (My trailer has H speed rated tires good to 130 mph). The result was going from around 13-14mpg towing to about 11 on a trip I do about 4-5 times a year so I have fairly consistent numbers for that route. That's why I took my 4.56 diffs back out and went back to 3.73 and then started looking at the possibility of having some 4.10 gears made. I also found that I lost a couple mpg highway empty. For me - that tells me the engine is working harder. City driving was much more enjoyable with 4.56 diffs though. If I didn't do a lot of 500+ mile trips, I'd probably have stuck with the 4.56.

Just my .02. YMMV. I still have the 4.56 and might swap them back in at some point if I stop doing the long road trips in the 4Runner or if I didn't live where posted highway limits are 80mph so you need to really go more like 85 just to keep up with traffic.

I suspect, but have no data to confirm, that the bsfc sweet spot for our 1GR is around 2,000-2,500 rpms and once you go much beyond about 28-2900 you're dropping fuel efficiency really fast. So the lighter load at higher rpms results in more fuel burn for the same power output.

 

[alphabeast]

I am still not dead set on the 4.56 vs 4.88. When I contacted Nitro to get their thoughts I had one guy say go with 4.88 and then another said 4.56. I think either way is going to be fine, but with towing (2k lbs) I am not totally sure...

 

[AMLOR]

7%.

4.88 gears will give you 30% higher RPM at a given speed than 3.73 gears. As I recall, I am turning about 2100 - 2200 rpm at 80 mph.

2200 RPM with 3.73 = 2878 with 4.88

2200 RPM with 3.73 = 2690 with 4.56

2900 is more than I like, but maybe not everybody drives at 80 mph.

You didn't mention what size tires you are running...

For sake of example: Mine sits at 2000 rpm in 5th, at a gps'd 70 mph. This is with the stock (worn) 265/70/17's
Using the 30% number, that would give me about 2600 rpm with the 4.88 at 70mph.
And no, I have no intention of towing at 80 mph...70 would be about the max. 65 is more realistic with the trailer.
The addition of 33" tires would also reduce the rpm another 3-3.5% below the above example depending on the exact tire.
It will be an interesting change if nothing else...

 

[firegod33r]

The deal breaker for me was that even with 4.56 diffs I still could not stay in 5th gear pulling my trailer. And I could hold 4th gear with 3.73 diffs. So my towing experience got worse, not better. I do tend to tow at 75mph when I can, so that might be part of the issue. I could slow down? (My trailer has H speed rated tires good to 130 mph). The result was going from around 13-14mpg towing to about 11 on a trip I do about 4-5 times a year so I have fairly consistent numbers for that route. That's why I took my 4.56 diffs back out and went back to 3.73 and then started looking at the possibility of having some 4.10 gears made. I also found that I lost a couple mpg highway empty. For me - that tells me the engine is working harder. City driving was much more enjoyable with 4.56 diffs though. If I didn't do a lot of 500+ mile trips, I'd probably have stuck with the 4.56.

Just my .02. YMMV. I still have the 4.56 and might swap them back in at some point if I stop doing the long road trips in the 4Runner or if I didn't live where posted highway limits are 80mph so you need to really go more like 85 just to keep up with traffic.

I suspect, but have no data to confirm, that the bsfc sweet spot for our 1GR is around 2,000-2,500 rpms and once you go much beyond about 28-2900 you're dropping fuel efficiency really fast. So the lighter load at higher rpms results in more fuel burn for the same power output.

I love reading about you guys experience with this kind of stuff.....I have been going around in circles to come up with the best possible solution for the lack of power and constant gear hunting while towing....... First I thought I would just dump the 4runner and pick up an F-150, maybe even a raptor. Then I realized that spending 15 to 20k on my 4Runner is much cheaper than buying a raptor or even an F-150 since my car is almost paid off.
Now Im wondering how a Super Charger would help vs re gearing. Of course It’s much cheaper to go 4.56 or 4.88 vs a SC install that costs of around 7k.
But I’m in the same boat, I have a 6x12 enclosed that I pull a bunch of times a year.....I was leaning more towards 4.56, but according to your trailer experience I may do 4.88. Right now stock on 265 tires It feels like the truck is struggling so hard just to keep 70 mph. I’m going 285s soon with a bunch of other stuff soon to be added (bumper, sliders, skids and RTT)

 

[delloro]

I love reading about you guys experience with this kind of stuff.....I have been going around in circles to come up with the best possible solution for the lack of power and constant gear hunting while towing....... First I thought I would just dump the 4runner and pick up an F-150, maybe even a raptor. Then I realized that spending 15 to 20k on my 4Runner is much cheaper than buying a raptor or even an F-150 since my car is almost paid off.
Now Im wondering how a Super Charger would help vs re gearing. Of course It’s much cheaper to go 4.56 or 4.88 vs a SC install that costs of around 7k.
But I’m in the same boat, I have a 6x12 enclosed that I pull a bunch of times a year.....I was leaning more towards 4.56, but according to your trailer experience I may do 4.88. Right now stock on 265 tires It feels like the truck is struggling so hard just to keep 70 mph. I’m going 285s soon with a bunch of other stuff soon to be added (bumper, sliders, skids and RTT)

If you want to see what it feels like to have 4.88 gears on the fwy, just leave (stock drivetrain) it in 4th. That's pretty close numerically to 5th gear with 4.88.

 

[Sundy]

I love reading about you guys experience with this kind of stuff.....I have been going around in circles to come up with the best possible solution for the lack of power and constant gear hunting while towing....... First I thought I would just dump the 4runner and pick up an F-150, maybe even a raptor. Then I realized that spending 15 to 20k on my 4Runner is much cheaper than buying a raptor or even an F-150 since my car is almost paid off.
Now Im wondering how a Super Charger would help vs re gearing. Of course It’s much cheaper to go 4.56 or 4.88 vs a SC install that costs of around 7k.
But I’m in the same boat, I have a 6x12 enclosed that I pull a bunch of times a year.....I was leaning more towards 4.56, but according to your trailer experience I may do 4.88. Right now stock on 265 tires It feels like the truck is struggling so hard just to keep 70 mph. I’m going 285s soon with a bunch of other stuff soon to be added (bumper, sliders, skids and RTT)

SC plus 4.56 would be a sweet combo, just saying

 

[rayofsi]

SC plus 4.56 would be a sweet combo, just saying

i have a sc. told ecgs everything i had in my truck and they told me 4.88.. somewhat regretting it, think 4.56 would have been awesome.

 

[firegod33r]

SC plus 4.56 would be a sweet combo, just saying

You are the second guy that has told me to go 4.56 if I do the SC.
That’s what I’m leaning towards now. Cheers!

 

[firegod33r]

i have a sc. told ecgs everything i had in my truck and they told me 4.88.. somewhat regretting it, think 4.56 would have been awesome.

What made you do URD vs Magnuson?

 

[Jetboy]

I love reading about you guys experience with this kind of stuff.....I have been going around in circles to come up with the best possible solution for the lack of power and constant gear hunting while towing....... First I thought I would just dump the 4runner and pick up an F-150, maybe even a raptor. Then I realized that spending 15 to 20k on my 4Runner is much cheaper than buying a raptor or even an F-150 since my car is almost paid off.
Now Im wondering how a Super Charger would help vs re gearing. Of course It’s much cheaper to go 4.56 or 4.88 vs a SC install that costs of around 7k.
But I’m in the same boat, I have a 6x12 enclosed that I pull a bunch of times a year.....I was leaning more towards 4.56, but according to your trailer experience I may do 4.88. Right now stock on 265 tires It feels like the truck is struggling so hard just to keep 70 mph. I’m going 285s soon with a bunch of other stuff soon to be added (bumper, sliders, skids and RTT)

At this point, I'm slowly putting my 4Runner back towards stock. Waiting to see what happens with the new tundra. And if it's not great, then probably buy a used LC200. The cost of the supercharger almost covers the difference in price between trading my 4Runner and buying a LC200 with similar year and miles. And I probably get the same MPG towing either way, but with the LC200 it's set up to tow a lot better. The downside is you give up a fair amount of off-road capability due to the size and weight of the Land cruiser or the tundra.

 

[gringo8251]

i went 4.88 and not sure if i needed it at all. i stopped driving my 4runner a little while ago. my new rcv axle boots leaked, and i'm due for my 500 mile diff oil change. hopefully when i get my 4runner back, it'll be a better drive.

Until then, my raptor is my DD.

Just had 4.56 installed and Harrop front locker. I decided against upgrading CV axles. Curious if you've put more miles on/time on the trail?

 

[AMLOR]

Living with 4.88's in a DD

SO, I thought I would pass on some of the things I have learned, and some “Real World” knowledge I have gained living with 4.88’s in a Daily Driver for the past 9 months.

This is in a 2019 TRD Pro with 285/70-17, E load range tires running 50psi in the front and 45 psi in the back. The truck weighs wet, 5740 lbs with no passengers or cargo. I, as a rule, run Shell E10/87 octane. I have been known to use Buckee’s Ethanol free fuel in 91 octane if the opportunity presents itself. NO, I cannot tell any statistical difference between them and the Buckee’s is .30 a gallon more expensive.

Let’s get this out of the way first…If fuel mileage is in the top 5 things your 4Runner just has to do well; DO NOT get 4.88’s. I haven’t seen the far side of 16 mpg in 9 months. 15.487mpg is the actual, calculated average, given where and how I drive over, about 6500 miles. Dallas Off Road did the conversion. $2500 TT&L out the door and was complete in 1 day.

However, before you decide that 4.88’s are not for you, consider this. The 4Runner now feels like it grew 2 cylinders and 50hp. THIS is how Toyota SHOULD have built the 4runner to respond. No Pedal Commander needed. 0-40, even with moderate acceleration comes up surprisingly quickly. Getting on the freeway is actually fun as the truck now pulls hard to 80+. The uninitiated might think it has a small V8 under the hood. Hunting/down shifting between 4th and 5th…essentially GONE. It is now a blast to drive.

Real World RPM. 65mph = about 2425rpm. 70pmh = about 2625rpm and 75mph = about 2825rpm. I say “about” because the Scan Gauge is so sensitive that an exact speed it hard to pin down. The gauge swings 30-40rpm either side even with the cruise control on. I personally consider 75 mph cruise as a usable max. 2825ish is just under half of what the engine is capable of spinning, and the truck will pull happily to 90+ if I need it to. 2825 also places the engine considerably farther up in the it’s torque band. Passing slower traffic is not an issue.

Would I do it all over again…YES! For me and how and where I drive this is a near perfect setup. One last thought. My wife and I are looking at overlanding campers. The leading contender weighs 2350 dry and has a 4800 GVWR. The 4.88’s will assist with this load. I am under no misconceptions about towing this much and road speed. 65-70 will be about it on the straight and level, 4th and 50-55 in the hills. If I’m lucky.
AMLOR

 

[jdm-v35]

SO, I thought I would pass on some of the things I have learned, and some “Real World” knowledge I have gained living with 4.88’s in a Daily Driver for the past 9 months.

This is in a 2019 TRD Pro with 285/70-17, E load range tires running 50psi in the front and 45 psi in the back. The truck weighs wet, 5740 lbs with no passengers or cargo. I, as a rule, run Shell E10/87 octane. I have been known to use Buckee’s Ethanol free fuel in 91 octane if the opportunity presents itself. NO, I cannot tell any statistical difference between them and the Buckee’s is .30 a gallon more expensive.

Let’s get this out of the way first…If fuel mileage is in the top 5 things your 4Runner just has to do well; DO NOT get 4.88’s. I haven’t seen the far side of 16 mpg in 9 months. 15.487mpg is the actual, calculated average, given where and how I drive over, about 6500 miles. Dallas Off Road did the conversion. $2500 TT&L out the door and was complete in 1 day.

However, before you decide that 4.88’s are not for you, consider this. The 4Runner now feels like it grew 2 cylinders and 50hp. THIS is how Toyota SHOULD have built the 4runner to respond. No Pedal Commander needed. 0-40, even with moderate acceleration comes up surprisingly quickly. Getting on the freeway is actually fun as the truck now pulls hard to 80+. The uninitiated might think it has a small V8 under the hood. Hunting/down shifting between 4th and 5th…essentially GONE. It is now a blast to drive.

Real World RPM. 65mph = about 2425rpm. 70pmh = about 2625rpm and 75mph = about 2825rpm. I say “about” because the Scan Gauge is so sensitive that an exact speed it hard to pin down. The gauge swings 30-40rpm either side even with the cruise control on. I personally consider 75 mph cruise as a usable max. 2825ish is just under half of what the engine is capable of spinning, and the truck will pull happily to 90+ if I need it to. 2825 also places the engine considerably farther up in the it’s torque band. Passing slower traffic is not an issue.

Would I do it all over again…YES! For me and how and where I drive this is a near perfect setup. One last thought. My wife and I are looking at overlanding campers. The leading contender weighs 2350 dry and has a 4800 GVWR. The 4.88’s will assist with this load. I am under no misconceptions about towing this much and road speed. 65-70 will be about it on the straight and level, 4th and 50-55 in the hills. If I’m lucky.
AMLOR

Thanks for the very in depth review with real world experiences over an extended period of time. In regard to cruising speed, it sounds like RPM change is significant. Would you say that it is not reasonable to cruise at 80-90 for a long period of time(hours) with 4.88? I am guessing high RPM and huge drop in mpg. In colorado, just driving outside the city warrants cruising speeds of 80-85 typically, not to mention speed driving between states.

 

[Nalcyon]

At this point, I'm slowly putting my 4Runner back towards stock. Waiting to see what happens with the new tundra. And if it's not great, then probably buy a used LC200. The cost of the supercharger almost covers the difference in price between trading my 4Runner and buying a LC200 with similar year and miles. And I probably get the same MPG towing either way, but with the LC200 it's set up to tow a lot better. The downside is you give up a fair amount of off-road capability due to the size and weight of the Land cruiser or the tundra.

What did you decided after reading about the new Tundra?

(got my 4.56's ordered last week I'll report once they are in).

 

[mrblah]

Thanks for the very in depth review with real world experiences over an extended period of time. In regard to cruising speed, it sounds like RPM change is significant. Would you say that it is not reasonable to cruise at 80-90 for a long period of time(hours) with 4.88? I am guessing high RPM and huge drop in mpg. In colorado, just driving outside the city warrants cruising speeds of 80-85 typically, not to mention speed driving between states.

drive in sport mode 4s for a few days (on your daily commute), to give you an idea of what regearing feels like and what your MPG will be. Although sport mode 4s is more like a 5.xx gear ratio. If you can tolerate driving in sport mode 4s, then you will like 4.56 or 4.88.

FYI, my vehicle is in the shop getting 4.88's. so i can only comment as to how I justified regearing. I can't comment on actual performance or why one gear ratio is better than the other.