I installed an Aussie Locker Model# XD-27527 in the front of my '93 4runner. One reason I chose to do this, was so I could give a real life running review on how automatic lockers act in the IFS. My truck is no longer my DD, but it does get driven on the street quite a bit, and many of my wheeling trips are not close by. It is not just a trail rig. I plan on being as straight up about the handling characteristics, and not sugar coating anything just because I have one. Hopefully this will be helpful for others who are researching automatic lockers for their 7.5" IFS.
First off, here is what I'm running.
'93 4runner 3.0 automatic
5.29 geared 4cyl diff out of a first gen 4runner
Lucas Heavy Duty 80/90 Gear Oil
33x12.5x15 tires
Aisin Manual Hubs
At this moment: Duralast Idler Arm with Downey Idler Brace and SDORI bronze bushings
I won't go into the install too much other than it was fairly easy and straight forward. Make sure you check your tolerances and write them down. You will need this info should anything go wrong with your locker.
This is going to be a "running" review, so as I come across different terrain, obstacles, weather, etc..., I'll add to the review.
Regular Street Driving (hubs unlocked):
Obviously no change to anything, driving and handling are normal.
Dirt Roads (mix of hard pack, loose dirt, steep climbs, steep and tight switchbacks):
Hubs locked 2wd- No change in handling or driving, only thing that is noticeable, is everyonce in awhile with the windows down and light throttle, you can hear the locker "ratchet" as it unlocks for a tight turn. It is very faint, only heard everyonce in awhile, and only because I was listening for it.
Hubs locked 4hi and 4lo- My first reaction was, Whoa! I'm not sure if I'm going to like this. The steering was real tight and hard, but as the locker got lubed up, it smoothed out, and wasn't as tight and hard. There is more resistance to turning, but still turns tight as it was doing a good job of unlocking. Even on tight steep uphill switchbacks, with decent throttle in 4LO, I was surprised how it was unlocking. The automatic tranny may be helping me here as it makes for smooth throttle control. One of the biggest things I noticed, was that after a turn, it returns to center instantly if you let go of the wheel. Going slow, it was no big deal, but while driving faster, it could cause problems if you let it snap back to center. If you are going fast enough, it would be like overcorrecting real fast. Just have to be mindful, to not let go and "steer" it back to center. After a few minutes, I had it down although it did "surprise" me from time to time as I slipped back to driving like I used to. By the end of the day though, I had relearned how to steer and it didn't catch me off gaurd anymore. I didn't really notice the sound of it "ratcheting" while in 4wd, I could just tell by the feel in the steering wheel when it was unlocked. I may have heard it a few times while in 4hi, but in 4lo, the engine is revved up to more rpms so I never heard it. All in all, I was happy with how it handled on the National Forest roads. I did not do any fast work with it as I had the whole fam with me, but by the end of the day I definately felt better going faster. My big fear was coming up to a turn at speed and not being able to turn, especially since I was on a ridge road with steep dropoffs on one side and sometimes both sides. To be honest though, on those type of roads, if I wanted to go fast, I would shift on the fly to 2wd anyways.
Sorry, that's all I've gotten to test it so far. Next will probably be the sand at Oceano Dunes and a local trail run. I'm really interested to see how it does in the sand at speed and how it will do on high traction surfaces like granite or Moab like rock.
Feel free to put your input in this thread as I want it to be a useful tool for those researching the auto lockers. I do ask that we keep it related to automatic lockers in IFS. There is plenty of info out there for the auto lockers in rear axles and front solid axles, this is purely for IFS automatic lockers. I would especially like input on the other brands and if a manual transmission makes any difference.