Toyota 8 in FB
 

This started out as "Ford 8.8 in FB" until I learned about the Toyota 8 option, which I'm pursuing.

Here are some of the advantages of the Toyota 8" rear end, some of which were already covered in the Ford 8.8 thread:

- Available off Toyota trucks in junk yards for a good price
- Reasonable selection of gear ratios
- Good selection of differentials (Toyota Supra parts can be adapted)
- 3rd member design uses adjuster collars (similar to a Ford 9"), which are easy to work with
- The axle assembly is similar to the RX-7, upsized 1"
- The axles are made from 4130 steel, which is arguably the best material available for the application, bar none
- The Wheel Mounting Surface (WMS) to WMS is 58.0", which is 1/2" narrower than my OEM GSL-SE rear axle; OEM Toyota 8 housing width is OK
- The thing is built like a brick shithouse:
-- The fill and drain plugs use hex plugs with crush washers for good sealing
-- The drain plug has a protective ring welded around it
-- The axle tubes have full height gear oil dams welded into their inboard ends to prevent oil slosh
-- The axle retainers are cast iron, with 4 M8 attach bolts
- Good reputation for strength and reliability in the RX-7 and Toyota 4X4 communities
- Lots of aftermarket support due to its popularity in the 4X4 world

Finding an Axle
 

I checked eBay, CraigsList, and Car-Part.com. eBay prices were too high and the parts were too far away. CraigsList didn't have enough selection. Car-Part.com worked out best. I live in Michigan, and although it was a mild winter, many of the better junkyards got socked in with snow, which made them reluctant to go check their inventory for gear ratio. I have a GSL-SE rear end now, which seems to have reasonable ratios for easy driving, so I wanted something simlar in my Toyota 8. The closest thing is a 4.10 (10 pinion teeth / 41 ring gear teeth). The issue is most junkyards don't know what ratio they have.

I finally found a yard in Toledo that had what I wanted -- a 1988 V6 (V6 and I4 Turbos have a stronger 3rd member housing and upsized pinion) with a 4.10 ratio. The diff was an open design, but limited slips in Toyota 4X4s are so rare, it's probably not worth the effort to find one. Price: $250.

I got it home, tore it down, and found out the lady at the junkyard had it right -- 10 pinion teeth and 41 ring gear teeth . . . and they all looked pristine! I didn't take any pictures of my new baby, but she wasn't very pretty anyway. She was covered in rust in some places and a crusted mixture of dirt and oil.

Next step will be to get the housing into shape.

Axle Housing
 

This was time-consuming and messy, but the end result was good. First, I used my die grinder with a cutoff wheel to remove all the brackets and mounts from the housing. There are a lot of them, and they are secured with healthy weld beads. The temptation here would be to use a torch to cut them off, but the heat from the torch can distort the axle housing. Besides, I don't have a torch, so a few nights with the die grinder (after correcting homework) did the trick.

I removed all the brackets, since I plan to create totally new brackets for suspension arms, springs, shocks, and brake lines.

After I removed the brackets, I went to work with a sanding disc and flapper wheel to remove the remaining rust and crud. This was time-consuming, but yielded good results. Sand blasting would be a good option, but I don't have one of those :).

Lastly, I wiped the whole thing down with solvent to remove any lingering grease and oil.

Differential Options
 

As I mentioned earlier, my rear end came with an open diff. My GSL-SE rear end has an OEM limited slip differential (LSD), and I've become used to it. I therefore decided that I needed an LSD for my car. There are many options available for Toyota Truck 8s, but I had set my eye on the Torsen style of differential for a few reasons:
- Longer lasting (in theory, since it creates less friction)
- More gradual transition from open behavior to locked
- Available as an OEM part in Supras
- T2R version includes friction plates for a "best of both worlds" design

I eventually bought a Supra Torsen LSD, and installed it in my 3rd member. I used the following site as a guide. I followed the process , except for the modifications to allow the 3rd member to fit: I created extra recesses in the housing instead of grinding the adjusting collars on the 3rd member.
http://gearinstalls.com/supralsd2.htm

If you're lucky like I was, the new diff will arrive with the larger bearings already installed (which are really only wider; OD and ID are identical for both bearing styles). The bearing on the side opposite the pinion will need to be replaced with a "small" bearing from the original truck diff.

I checked the gear contact pattern afterwards, an it was ideal!

good stuff, i have heard about the 90's kia sportages pinion gear bolting on to the GSL-SE diff housing. where i am at there are not a lot of people that work with these cars.

Ive once briefly thought of a toyota rear end in an fb. glad to see your giving it at try. im excited to see your progress.

And just to be sure, the 5 bolt pattern is the same as a mazda 5 bolt? (Turbo FC/FD/Ford/ etc)?

If you called up a junkyard what did you use as your search term? (car model/year?)

Great progress Elwood!

The Toyota truck rear ends are 6 lug so some machining will be needed. I also plan on doing this swap at some point and posted some info I found in his other thread. To keep it all in one place though I'll copy it below:



Found a good site with lots of info on the Toyota 4x4 parts here: http://www.4x4wire.com/toyota/faq/parts/

Looks like 86-95 is what we're looking for and can be either 58" wide or 58.5" wide in the case of coil sprung 4runners

In case that site goes down, here is a copy of the info:


Year: 1986-1995

Gearing: 4.10, 4.30, 4.56, 4.88

Width: 58"-58 1/2"

Ring Gear Size: 8"

Shaft Size: 1 5/16"

Spline Count: 30


Notes: 10" rear drums, V6 and turbo applications used stronger third member with larger bearings and bigger third member, coil sprung 4Runner axles are 1/2" wider than pickup axles, factory 4.88s available in vehicles equipped with automatic transmissions starting in 1992, but the pinion is moved closer to the ring gear than on all the other 3rds. This makes it so they can use a standard thickness ring gear instead of an extra thick one. This "thin" 4.88 gear is only made by Toyotas.

Adapting Axles
 

As was just stated, FB wheels won't fit on the OEM Toyota axles. The Toyota 8 is a very good match for the application . . . but not that good. An unfortunate design element of FB axles is that the registers or pilots for the disc and the wheel are both included in the axle -- and they're different. These are important to me because it's this pilot that centers the wheel and rotor properly and ensures smooth, round running at high speed. The studs alone won't do it.

To make the Toyota axles act like Mazda ones, I made some modifications. The specifics are included in the attached drawings (my best PowerPoint work). The key is adding a "double-step pilot piece" that will be attached to each axle with an M12 bolt and Loctite. The other elements are typical wheel bolt circle changes.

I took my axles to a local machine shop, and he agreed to do this in his spare time for about $100 for the pair.

I also dropped off these parts to make sure everything would fit:
- ARP 12MM extra long studs (8 pcs)
- GSL-SE brake rotor
- Brake rotor retaining screws
- A wheel

You sir, are awesome :)

Personally I wouldn't bother with the rotor retaining screws, but they can't hurt

I just noticed a mistake -- the small bearing goes on the side of the differential opposite the ring gear. Also, here are pics of the protrusion of the adjusting collar and required reliefs in the housing so the 3rd member will fit.

Just to reiterate. Which application rear did you get? There's like eleventy billion of them.

Subscribed. I am glad to see you are pursuing this. Keep up the awesome work. It will make it easier for me later ;)

See "Finding an Axle". It came from a 4Runner, which I didn't mention earlier because I don't think it matters. The trucks in that year range had the same rear axle option.

Thanks -- I do hope it makes it easier for others (my contribution). In return, I hope you "check my math" and catch any mistakes before I make them (your contribution).

2wd or 4wd? They're different.

4wd

Nice work Elwood! Thank you for sharing!

Just curious if you know the weight difference between the Toyota 8 rear and the Ford 8.8?

Steve

Great work Elwood!

Do you or does anyone here have a weight figure on the stock (OEM) rear-end assembly? I searched to no end. Also looking to find out the difference of the two 8" rear-ends.

Thanks! Keep up the good work! :icon_tup:


-Bern

Toyota 8 vs. GSL-SE Weight
 

Since I haven't made the suspension brackets and spring seats for my Toy axle yet, I had to estimate that weight.

Also, my GSL-SE rear axle is modified for tri-link / panhard / track use:
- Upper trailing arms removed
- Watts link stud removed
- Brake backing plates removed
- Panhard bracket added
- Tri-link bracket added
- Inboard oil dams added (steel)
- Additional oil fill port added (more capacity)

I'd guess that these changes dropped my axle weight a slight amount, but I'll call it insignificant -- in the order of a pound or two.

I plan to re-use my GSL-SE calipers, so the weight of the brake assy will be the same in both cases.

If you look at the pictures, you can see that the Toyota 8 is significantly heavier duty in design. There's a lot of weight in the cast iron 3rd member with the 8" ring gear. The Supra differential is a factor, too. It weighs about 22 lbs all by itself, and is noticeably heavier than the original 4-pinion open diff.

With all that, I came up with a 23 pound delta between the two -- less than I had guessed.

Thank you for the excellent information and write-up. I had read that the 1st gen axle was in the 160lb range, but never confirmed it; your work seems to prove this right. And 23lbs is not bad at all for the Toyota rear-end.

-Bern

i have been eyeballing this threat....vary good info:icon_tup:..i would like to do the same..good work bro

cool stuff bro..there was someone else on the other forum that had similar info on these rears. ..Did you get any help with this setup?

.http://*************.com/rotary_foru...ht=toyota+rear

Thanks for mentioning. I'm changing my suspension geometry, so I don't need/want the original brackets. I'll post some drawings to explain . . . and eventually pictures.

But I do need caliper brackets and spring seats, so your info is appreciated. I just sent them an e-mail for pricing.

Most definitely archive worthy.

Archived!