Differential Gearing

For those of you with aftermarket differentials, what ratio are you running and are you happy with what you chose? Where did you purchase them? Did you do the install yourself, or have someone do it? What was the pricing for the differentials, labor/install? Any other things I should know that I didn't ask about?

I am interested in 4.56 gearing, rear locker and possibly a True Trac limited slip front differential.

I assume with aftermarket differentials, I'm going to lose the OEM rear locker?

If it matters, I am familiar with differential and transmission ratios. I've driven various auto/manual transmissions, with 3.07, 3.55, 3.73, 4.10, and 4.88 differential gearing, with tires from 29" to 34".

 

There are plenty of threads with pics on this subject. Suggest you go on the search box and type "regearing" and get a nice cold one as you read. I went with 456 as I don't intend to run 35's and I have a SC unit as well. Love the 456's and the low end torque gained thru this new process. Good luck.

 

4.88 Nitro. I had a shop do it, they threw a front locker there too

 

Thanks @ChessGuy I did a search first. I got about 1M hits dealing with upgrades, not specific to gearing, and whether first gear was too tall, too low, miles per gallon, camping gear and a host of other things. Things specific to my questions though, I didn't find much of. Maybe because I only had one cold one, and I need a 12-pack to wade through all of the things that aren't really about regearing.

ETA: I did a new search, title only. Seems this isn't done very often, compared to some other vehicles.

 

Yeah, I think the choices here are really on 488's or 456 for the 4R. If you intend to go all out with your 4R, that is, bigger tires, tents, bumpers, skids, then you need the 488's. If it is a mild build, staying with 33's and just occasional offroader, then 456 is the way to go. My recommendation is that you go with ECGS and get their fully and ready assemble third members and do it yourself if you are handy enough and have the right equipment and maybe some help. Other than that, you need to find a reputable shop that knows what they are doing. I didn't get a front locker on mind because I don't think the 4R needs it, I have convinced myself that if I turn on ATRAC and the rear locker at the same time, I have essentially the same functionality of a front locker. (or a poorman's locker that is). Regearing is probably one of the most underated mods, IMO. I think the 4R is different with it. Good luck and post pics on what you do.

 

My last vehicle had 33" tires and 4.88 gearing. I thought it was perfect. The transmission gearing is similar between the last vehicle and a new 4R, without a sixth gear. I think 4.56 would be better, for me, with a 4R. I plan on a narrow(er) 32" tire on the 4R.

Now I'm looking for t-case gears through Marlin Crawler.

 

I agree search function pulls up all kinds of crap not related to what you are searching. Spend a lot of time going through all of these posts.

I believe in opening up discussion on topics, after all that is what we share the forum for.

Anyway out of the factory these things don’t have proper gearing for what they are. Need to keep the EPA happy. Depending on usage and location will be a determining factor between 4.56, and 4.88.

I went with 4.88’s to help with my power loss at altitude mountainous terrain and long pulling grades on highway. 4.88’s and the word supercharger would not even pass your lips.

You will retain factory locker reusing the carrier just bolting up the ring gear to it. Different pinion gear.

I won’t discuss pricing because I don’t want to open a pissing discussion. But price out the gear kits and subtract that from the quote shop gives you indicating what there labor cost is. Some of these labor charges are atrocious.

 

Thanks. I was going to do differential/3rd members myself, but I think I'll contact a shop regarding r/p install so I can reuse the carrier/locker. That probably makes most sense. I just contacted Marlin Crawler because I really wanted their 4.7:1 t-case gears, but they've said it's not an option for the newer 4Runners with a chain-driven case. I've asked about their Tacobox though, so maybe that's an option. I'd really like a crawl ratio closer to 50:1 or even better 60:1, but not sure I can get there easily.

 

There is no harm in going 4.88

 

Brought my crawl ratio from 35:1to 45:1 with gears and 33’s. Which is not ideal, but it is what it is. Better gearing in the transfer case would be outstanding. Like 4:1 bring my ratio to 68:1

 

Yeah, I'm having a hard time with the crawl ratio. Jeep offers a 5.13 first gear, 4:1 t-case and 4.88 differential gearing from the factory. That's what I was driving until two days ago. First gear, at 5.13 was too low for around town driving, made for quick shifts or starting out in second (there's a terrible spread between first and second in the factory manual trans). What was nice though, 100:1 crawl ratio. I think 34:1 of the stock 4Runner is going to drive me crazy. Trying to make a big enough difference with just a differential gear change makes for a big change 100% of the time, instead of putting some of that change in low-range. I'd be happiest to change my diff ratio by 20% or so, then go 30% or more in the t-case.

My first Wrangler had a 32:1 crawl ratio. It was terrible.

 

I recently had a set of 4.88 Yukon gears installed. It was installed in a single day by a single person who is the only gear person in the shop. He did a fine job and no problems.

 

Yep, I've had a shop, one guy, do gears for me. Took him 4 - 6 hours to do front and rear diffs with True Tracs (lsd carriers). If you know what you're doing, it's not too hard. Complete 4Runner 3rd members would be even easier.

 

As someone already stated, ECGS does this for a living. Is there anyone else out there who do as many 3rd members? They really have the process figured out so you can trust them.

I have 4:88s running 35” Toyo MTs, I also had them install ARB front and back. It’s been flawless! I like the 4:88 to help manage the extra unsprung weight.

Enjoy!