I love the Toyota axle and I agree that the Toyota axle is very strong, especially with upgraded axle shafts. My problem is that the only matching gear ration between the Toyota axle in the rear and the Dana 44 upfront is the 4:88 which is great for 35" tires but a little undergeared for the 37" tires. I want to swap to an axle where I can get a matching set of 5:38 gears. That leaves my options to a 12 Bolt or Dana 44 (which are actually weaker than the Toyota axle), a 14 bolt, Ford 9", or Dana 60.
I did a bunch of research on this and if I just swap in a 14 Bolt, Dana 60, or any American axle like that the brakes are bigger so I would have to swap out the master cylinder and brake booster. The second minor issue is the speedometer on the 4Runner is tied into the rear ABS sensors. You can get around this by changing the electronic speedo to the manual kind like in the Tacoma's. I was just looking into the Dynatrac Dana 60 because it a bulletproof axle and they can make it to the width I want with the 6 lug pattern that takes the stock Toyota brakes and accepts the ABS sensors. Just seemed like an easy swap, just an expensive one.
Are you talking about buying a Dynatrac
rear 60? I'm assuming so based on your trying to match the ratios with the 44 front. Just want to be sure.
BTW,
DO NOT buy a high pinion/reverse cut Dynatrac 60 for the rear....get a standard rotation/low pinion for a rear application.
That said, it makes no sense to spend that kind of money to get the brakes you want....Now going 6 lug? That will cost a lot more money, especially if you want a Full Float D60. The pattern is a lot smaller for 6 on 5.5" rather than 8 on 6.5" and the axle flange takes up a fair amount of room. It can be done, it's just expensive.
What's your width up front? WMS to WMS is probably north of 67"....what are you doing about the rear axle width now? Wheel spacers or different wheel backspacing? Factory width is around 60"....so that's at least a 3.5" difference on each side.
If you're married to 6 lug wheels (I can't tell what kind of investment you made in wheels)....an FJ80 rear axle makes some sense as it's full floating and 6 lug....but they're only 63" wide....and you'd need 2" spacers or you could buy a Ruff Stuff or Diamond rear and make custom shafts....but that's not really the cheapest, strongest or best way to achieve your goal of ratio compatibility. A better matching option (but one that isn't full float) is a Tundra or T100 rear axle....still the misnamed 8.4" semi floater, but 67" wide WMS to WMS. You're still going to have to buy a locker unless you want to mod the factory Tundra housing to take an E-locker (again, not sure what you have in the rear now). Problem is: still doesn't solve your issue with mismatched gears.....which brings us to the next point.
As for 5.38s and 5.29s.....lots of guys on Pirate do it. If you're running hubs up front and not flanges....it probably makes almost no difference whatsoever since you're only engaging the front end on low traction surfaces. If you wheeled Moab a lot, I might be less inclined to run the different ratios...but plenty of people do. I'd recommend researching on Pirate. This site just isn't really geared toward the level of modification you're doing/have done.
You could scour the boneyards for a 6 lug D44 out of a later 70's model Chevy 1/2 ton....but they're hard to find. In spite of what Toyota guys say, the 44
is stronger than the Toy axle...not by much, but it is stronger....from housing to gear size to taper cut vs. hypoid to adjustment....the 44 is the better axle. The Corp 12 bolt isn't....but mainly b/c it's got 7/16" bolts holding on the bearing caps and it's a c-clip piece of junk axle. I ended up getting a 5 lug Ford D44 out of a late 70's F100 or F150 and had the flanges redrilled for a 6 on 5.5 bolt pattern. Most rear D44s out of half tons will only be 65" wide though....but I cut down my front D44 about 2 1/8" (to a size that used a shorter factory long side shaft) so the WMS to WMS was about 65.25" or so.
As for not wanting to swap master cylinder and booster....that is relatively minor, especially factoring in the cost of a Dyantrac axle vs. a boneyard one and new MC/booster.
Honestly, your best bet is to bite the bullet, get new 8 lug wheels, buy a 14 bolt rear and 8 lug front D44 rotors and change to the appropriate MC (booster should be fine). All the parts will be readily available (nothing custom other than maybe an adapter plate to your booster.
Heck, You could almost buy and build a front 60 and rear 14B for what you'd spend on the Dynatrac.
