Off Road EnhancementsEnhancements to improve your off road travels
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The differential found in the back of many Japanese trucks (and certain domestic axles such as the Ford 9") is mounted in a removable housing that allows for it to be set up at a work bench. This is the case for the rear end of all Toyota trucks and 4Runners. One benefit of this is the ability to swap gear ratios around between trucks. While this isn't difficult to do, it helps to know the steps involved, if for no other reason than to plan how much time to set aside. First time I did this it took me about 4 hours, stopping for break, and cleaning the underside of the truck at the same time. Your mileage my vary.
Note: Sorry, I don't know torque values. They are available in the FSM link, or by searching. Tools:
10, 12, 14mm wrenches
10, 12, 14mm sockets and socket wrench
24mm socket for diff drain and fill plugs
>3" socket extension
razor blade or gasket scraper, steel wool is also helpful
empty beer bottle or jar, as well as 3 feet clear 1/4" tubing for bleeding brakes
a wheeled creeper is helpful
some sort of jack
oil container to drain oil into.
3 quarts (actually 2.3 quarts) 80W90 gear oil (or thicker- I use 85W140 to quiet my locker down)
minimum a quart of DOT 3 brake fluid
oil resistant RTV sealant (I've used black, ultra grey and ultra copper, none leaked)
blue (med strength) thread locker.
PART I- Third member removal procedure:
Take the truck for a spirited drive to warm up the gear oil.
Disconnect the 4 14mm bolts securing the rear driveshaft to the third member. Sometimes you need to get a chisel in there to separate the axle from the pinion flange on the third member.
loosen the lug nuts
jack up the truck and support it with jack stands
open the differential fill plug bolt, THEN undo the drain plug. The rational behind this is that if you drain the oil, then find out there is no way to refill it, you're looking at hiring a flat bed to take your truck to a mechanic to get the fill plug open
Remove the wheels, then the drums. The drums are simply sandwhiched between the wheel and the hub.
With your fingers or a set of pliers, undo the parking brake cable.
Undo the 4 bolts securing the hub to the axle housing.
Undo the brake line where it enters the back of the backing plate (not sure what exactly its called, please correct me if you do).
Get a plastic bag and put it over the open end of the brake line. Secure with an elastic. This prevents the brake fluid from gravity bleeding out of the line. THis is quite important as is all the brake fluid drains out (over several hours) and the master cylinder drains dry, then you've got to bleed the MC (lots more work).
the axles should pull out freely from the axle housing now. Remove them completely (best not let rest them on the axle seal, as the axle may start leaking) and set them aside. Here is the seal you are trying to avoid damaging.
Unbolt the third member from the axle housing. I think there are ten 12mm nuts to remove. Keep in mind this thing weighs about 60 lbs and you don't want to just drop it after undoing the nuts.
I find it easiest to position myself under the axle laying on a creeper and wrestle it out onto my chest. If you have a rear swaybar, the diff may catch on this. To remedy this, you can unbolt the swaybar end links from the frame.
The install is basically the same as the removal, with a few extra steps.
You must scrape the gasket material off the mating surfaces of the axle housing and third member. They must also be free of oil. I use break cleaner on the surfaces once most of the oil is gone. Once this is done, apply a 1/4" bead of RTV gasket material on the third member making sure to go completely around each bolt hole. Then place the third member into position and bolt into place. Only tighten the nuts a little more than finger tight just yet. Let the RTV sealant dry (vulcanize actually) for an hour or two then tighten the bolts to (the appropriate torque).
Apply liberal amounts of blue (medium strength) thread locker on the driveshaft-third member bolts and the 4 bolts which bolt each end of the axle housing to the hub.
Reattach the rear brake lines after removing the plastic bags, and tighten the bolts to 7ft-lbs (not much at all, even with a 6 inch long box wrench. Finally bleed the brakes. There are plenty of writeups on this, so I'll let you search. Here's one: http://www.4x4wire.com/toyota/mainte...leedingbrakes/
If any grease/oil got on the rear brake shoes, spray it with brake cleaner.
REMEMBER to refill the axle with oil. The thinnest oil I'd use is a 80W90.
PART II- Installing the a lunchbox locker
Note: this is the procedure fir a 4 cylinder rear diff, although many of the more difficult steps are the same.
spray down the third member with brake cleaner to make the job less messy
place the third member in some home-made jig to hold it still.
Mark the adjuster nuts relative to the bearing caps, use different markings for each side (ie: I used a double punch mark on one side, and a single one on the other)
Its crucial to make sure the bearing races and marked bearing caps go back on the side of the carrier they came off of. I used to marked plastic bags- one for each side.
Mark the ring gear relative to the carrier.
Remove the ring gear from the carrier with an impact wrench or use whatever you have (do not apply a torch).
With a drill bit about the size of the roll pin, drill out the dented toll pin hole
tap out the roll pin using a nail or sacrifical punch or drill bit.
the cross pin, spacers and spider gears should fall out. Keep track of which shim washer came from which side as these are re-installed with the locker
Assemble the locker (really simple to do, no explanation necessary), take the measurements its asks for with a $3 feeler gauge from an autoparts store. Note bags used to prevent grit from getting in the bearings.
Put the roll pin back in and dimple the opening with a punch to prevent the pin from backing out
tap the ring gear back on with a piece of wood. Remember to lined it up so it is the same orientation as when you removed it. If it is too tight, warm it up until it is too hot to hold for long, but not long enough that it burns you (or else you may ruin the metal temper). Bolts ring gear back on to carrier. Use red thread locker and torque to spec.
Apply aluminum-based anti-seize compound to the treads of the bearing cap, third member and the outside of the bearing races
Place races in on the bearings (on their respective sides- don't mix them up!!!) and lower the carrier into the third member.
Place adjuster wheels in position on their respective sides (or else markings will be useless)
Place the bearing caps in positions (again, on their respective sides) and hand tighten the bolts.
IMPORTANT STEPS that I misread the first time:
Make sure the adjuster wheel thread aren't cross-threaded, then tighten the ring gear side adjuster (teeth pointing AWAY from this adjuster wheel) until the backlash is zero, then back the adjuster out until the punch marks lines up. This should be less than one full turn. Tap on the bearing cap as you're doing this to make sure the treads settle properly.
^ maybe not
Tighten the other adjuster wheel (the side being faced by the ring gear teeth) until it reaches it's mark and has some resistance to turning any tighter.
I copied Zuk's adjuster tool. Its just a flat piece of metal with two bolts going through it that line up with the holes in the adjuster wheel.
Once the BL is reset, torque both bearing caps down and bolt on the little adjuster wheel lock.
Re install the third member as described above.
After the locked third is re-installed in the axle and the axle filled with gear oil. Jack both rear wheels off the ground and put the tranny in neutral. Spin the tires by hand one way then jerk it the other way, it should unlock from the other tire, and make a clicking sound. If so, the locker is good to go for a drive.
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My '86-95 4Runner/ truck writeups SEE HERE
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Originally Posted by DaveInDenver
Yeah, I do think it's sort of funny. Can't you see a roomful of Toyota engineers looking at a relay rod, scratching their heads and saying 'Hmmm, this part wore out after 200,000 miles and 16 years, this is just unacceptable.'