Tundra diff swap

I have a 2012 4.0 with 3.91 gears, 35” tires have really dug into my gas mileage, I have peaked interest in having east coast gear supply send me a 4.88 core in order to compensate for the changes in my drivetrain, plus being a V6 I’m sure it wouldn’t hurt. They gave me a great price around 1050 after sending back my stock core but I can’t find any material on doing the swap. Anybody have any info? I’d appreciate it greatly

 

Gear swaps are difficult to get everything set up properly. Personally, I would never attempt. I would take to to a reputable local shop that has experience in setting up differentials. You can waste a lot of time and $ quickly if it is not performed properly.

If you search this site, there is a thread or two about gear change installs. The job is beyond most DIYers.

 

look here

https://www.tundras.com/threads/diy...ntial-regear-at-home-not-for-beginners.67185/

 

I've done dozens of them. If you are talking changing the ring and pinion you'll need special tools (mainly for the pinion gear). But if all you're doing is swapping the 3rd member (the center part of the axle) that's much easier. Basically you need to remove both axles and the driveshaft and then it'll come out when you unbolt it. The driveshaft is obvious, 4 bolts on a flange. The axles are a bit harder but I'm sure there's plenty of youtube videos on how to do it.

I don't know what size ring gear is used on the V6 so I don't know how much the gears would cost. But $1000 seems a little high to me. A set of gears with shims would probably be about $300. A competent company could do the swap in an hour or two in the 3rd member. Shipping would be the killer as it's all there.

If I was going to do it I think I would add a limited slip (if they make one for your size R&P). Might as well go all in. Another thing to remember is that when you change the gear ratio you also change the speedometer. Back in the day of cable speedometers companies made adapters that mounted to the transmission (or transfer case if 4wd) that compensated. I would also call around and see if you can find a local place that can do the work to avoid shipping charges.

 

Swapping the entire 3rd member they’re shipping it to me set up

 

If I remember correctly the biggest issue with removing the rear axles are the brake lines. There's a clip that holds the hose to a bracket that will be removed when you unbolt the axle. It's basically an oval hole that the line passes through. I'm sure the common way to deal with it is to cut a slit in it so you don't have to break the brake line (and then bleed the brakes). The other issue could be the anti-lock brake sensor. I've had them become difficult to release the clip to unplug them. The plastic get brittle and junk gets in the connector. If you are doing it to just replace the 3rd member then you don't even need to remove the brake rotor/ drum. Just remove the calipers, antilock sensor cable, and the parking brake cable. Then remove the 4 nuts holding the axle in place and it should come out. On my 1st gen there's a seal inside the tube so you have to carefully remove the axle all the way. It'll have gear lube on it unless it's been sitting over night after being drained so have some old rags ready.

If you are planning on doing this remember that the 3rd member is heavy. You'll need to lift it into place. If on jack sands while you are laying on your back that can be difficult. Every so often on Roadkill Garage they change one. Be safe and put good blocks on both sides of your front tires to prevent it from rolling as your parking brake and transmission aren't going to do a thing to prevent it from rolling.

 

The third member sounds extremely expensive to ship back for a core charge with the weight

 

Yeah I ended up not even doing it, I realized a regear is gonna make my truck undrivable at highway speeds, answer is not to run pavement pounder 35’s on a V6 tundra lol it looks cool but doesn’t do anything good for me other than looks

 

It depends on what size the original tires are. Changing the gear ratio could just make the engine RPMs go back to where they should be with larger tires. Even if it was a bit too far it may not be a bad thing. Way back when I worked for a glass company that bought a 2wd Toyota dually 2wd that had a heavy rack for holding glass (Uhaul also used them). Back then (late 80s) the 4wd trucks came with 4.10 gears while the 2wd had 3."somethings" (can't remember now). With stock tires the 22RE engine struggled on the interstate going anything over 55. You pretty much had to put the pedal to the floor.

Years went by before the breather plugged up blew all the oil out of the diff. Of course, being a company truck, nobody did anything until the R&P were shot. When the boss started getting quotes in the thousands I suggested putting in a spare set of 4.10s I had. Of course the original impression was that it would make the motor rev too high but we needed the truck and I wanted to try it. So I swapped them over and the truck changed from a dog to actually having some power. The fuel economy also went up because you no longer had to put the pedal to the floor.

I doubt that a v6 Tundra running stock tires is lacking too much in power but you might be surprised that having a little extra RPM could be a benefit. I don't know anything about what size R&P your Tundra has (is it the 10.5") so I don't know what combinations of gears can be purchased. I do remember useless information like that a late 80s 4wd automatic had a R&P ratio between 4.10 (sometimes called 4.11) and 4.88. I think it was 4.56 but nobody carried them. Back then if you had 31" tires you left the gearing stock. If you went with 33" tires then 4.88 were what you wanted. I was running 35" Super Swampers with 5.29s.

 

Toyota’s 22RE was the best 4 banger ever made. I had an 80’s Celica and Pick-Up and both went over 400K miles without ever having to do any major work to them. They didn’t come out of the factory with a lot of power, but were easily “hopped up” with a cam, headers, and exhaust.