Hello all.

I have a 1988 4Runner DLX. I just bought an 85 SFA housing so I’m trying to gather all of the parts before I have my buddy help me tear into this thing.

I was looking online and it was saying that the third member from a T100 would work as long as it’s 7.5”
I’ve seen third members on eBay anywhere from $400 up to $800 used.

I would like to keep the option of putting a locker in the front as well.

I was also looking at different hubs because from what I’ve seen the solid front axle needs a 30 spline IFS is 27.

thanks for any advice

 

The third member for your straight front axle should be an 8 inch ring gear type, interchangeable with the one in the rear of your 'Runner.

Not a 7.5 inch unit.

 

Millball is right. It's an 8" diff. I've built three 85 front axles. The rear you have now would fit perfectly. I run high pinions from an 80 series Land Cruiser to help with drive shaft angles. Still an 8" diff. You can also run the V6 rear diffs if you want. Like from the 2nd gen 4Runners and 3.0 pickups. Still an 8" diff but a thicker housing. You can read up on Toyota 8" diffs on Pirate 4x4 forum under Toyota bible or plenty of other sites.

Yes the locking hubs from the IFS are different than the SA locking hubs. You can either buy new or used hubs or get conversion parts for the IFS hubs.

Speaking of hubs, you may want to use your IFS wheel hubs to do a big brake upgrade with slip on rotors and have a wider stance to closer match your rear IFS axle width WITHOUT using wheel spacers. Search Tacoma brake upgrade to get started.

Budget for some RCV axles. I personally think axles need to be upgraded. Unless you are staying small tire and low power. You will need chromoly hub gears to go with the axle upgrade if you ever need to warranty them. Some axle packages include them.

Be super careful welding all your gussets and brackets on the stock housing. It's super easy to end up with a bent housing because of the welding. An axle alignment bar is best but it can be done without if the welder knows what they are doing.

If you are using OEM knuckles I also suggest upgraded knuckle studs. I've used TG and ARP both. They are expensive so I usually bought them on Black Friday or other good sales. Summit Racing usually had the best deal to my door.

If you're going big tire you might want to do hydro assist. My stock steering system didn't do well with 35's. It was fine when I only had 31's.

Take your time with axle placement. Don't weld anything solid until you KNOW where it needs to go. My 88 pickup needed the steering box moved forward. My son's 91 was OK in the stock location. Put a bar across your frame inside the bushing tubes you will be welding in to keep them parallel and aligned. Pay attention to your tie rod and drag link position/alignment to make sure they don't hit each other when your suspension cycles and you steer.

My rag joint couldn't handle the 35's so I eliminated it.

Good luck with your build!
Scott in AZ.

 

What is your end plan for the truck and tire size? What type of wheeling do you like to do? Start a thread in the build tread section as you start diving in!

 

Thanks for the advice.

 

Sorry for no updates. Really haven’t done much since the first post.

so I found the third members around $500. Does it matter if it’s front or rear? As long as it’s 8”? I’m about to pull the trigger on some parts

 

I found a third member. I believe it’s from a turbo. It’s an 8” so I’m happy

i want to add lockers and change the hearing to at least 4.88 maybe 5.29. I plan on running at least 30” tires. Any advice is welcomed

 

You're going through all this work and money of a solid axle swap to run only 30" tires?
With 30" tires, 5.29 gears would be WAY too much. 4.10 would probably be closer to what would be good, depending on what you plan to do with this truck

 

My 88 with the 22RE and 5 speed manual transmission had 4.56 gears and 31" tires when I got it. Was perfect.

4.88's would be more appropriate for 33's with a 22RE and 5.29's are what I run now with 35's and 37's.

Like mentioned, the stock 4.10's would work for 30" tires. 4.30's if you really want to change gears. That's what my 86 with a 22RE and auto trans had.

 

more than likely gonna run 33” it’s a good size for that truck.

so do you think 4.88 would be good or should I put 5.29 in there in case I wanna run bigger tires? I also want to add lockers. I’ve seen people put a lunchbox style in the front and an air locker in the rear.

 

The 4.88's will be a good match for 33's and a 22RE and manual trans. Especially for daily driving on the street. If you're really thinking of 35's just do it and get the 5.29's to match. If it's a trail truck only get the 5.29's. Just MY opinion. Maybe other's will chime in.

I have Aussie Locker's in both axles and have been running them without trouble since I did my SAS. (2010 ish?) One of them I bought used. I was on a low budget and planned on running them until they failed and then run Yukon Grizzly's. It's been many years of hard wheeling and daily driving. I personally prefer auto lockers for their simplicity but they are on all the time and take some getting used to.

You can run whatever lockers you like. You better get some good axles in the front to go with it.

 

axles and brakes are next on my list. Definitely gonna go chromoly with new Asin hubs. Everything I’m seeing points to an air locker. I did see a video where a dude retrofitted an E locker from a 96-02 4Runner to his 88..

it’s gonna be a daily/wheeler.

 

moving up to 35" tires is a big step, in part because you start being concerned about things like the tire hitting the cab on the front end... the old skool way was to pound down the welded seam area, but if you think that there is any chance that you'll get serious and move to 37", consider moving the axle forward now... but that's another big can of worms.

the idea is to do it all together, at once... air lockers have some advantages but it's also another failure point, if it leaks inside the axle housing for instance you'll probably have to pull the diff to fix it?

 

here is a general idea of what's involved, albeit there is a lot that's not shown.

i'd start with putting the third in your housing and seeing if the axles slide in, to help confirm that it's not a bent housing.

 

So I found this locally. Got it for $2000. Clean title. So now I’m thinking about just doing a body swap😆🤓 I may SAS my 86 pickup now in the future. Looking for a rig with a decent body now.

 

you want to swap that body out? it looks fairly straight... one of the most important factors would be rust around the windshield, it gets down into the pillars and rusts out from the inside.

looks like solid engine mounts, somebody has wheeled that rig

 

yeah the dude who I bought it from was no stranger to the dirt. The body is pretty clapped out. Especially in the rear. I almost had an 88 bought but the dude wanted too much for it. I have another 88 4Runner that is in decent condition. Might transfer everything over..still looking for a few things. I’m anxious to get started now!


Here’s a pic of the 88. It’s a real good picture 😆