Another 4LO beeping thread.. complete with stupid question!

[chili]

Hi all- New 4Runner owner here ('04 V6 Sport 4wd, 130k mi). I've scoured this forum and already come across some fantastic information for various fixes. A liberal application of WD40 on the steering column u-joint solved my steering issue!

I have the dreaded 4LO beeping/failure of 4LO to engage. 4HI and the CLD work fine. Given what I can put together from the history of the truck, 4LO has probably never been used. I can hear the actuator trying to move its mechanical components, complete with the "faint beep" from the actuator itself. A replacement T-case isn't in my budget for a while, and yes, I do want to use 4LO (that's one of the reasons I got a 4Runner!).

I have tried all the potential fixes (I think) noted in other threads including:

1) Following the exact instructions in the owner's manual for putting the truck into 4LO
2) Trying all suggested combinations of switching between 4HI/4LO with/without CLD engaged, after Drive, Reverse, on a hill in both directions, wheels turned, at various operating temps, etc
3) Tapping (ok, whacking) the case with a deadblow hammer while a helper operates the 4LO switch back and forth
4) Loosening the actuator mounting bolts at least 1/3 inch and moving it in every direction, also with a helper operating the 4LO switch

The only other reasonable/cheap fix I can think of is a fluid change, but if something is sticking from lack of use, I doubt new gear oil will make a difference, so my stupid question is this:

How bad would it be to drain the T-case and squirt a bunch of *something else* in there (i.e. WD40, probably NOT penetrating oil), move the truck a foot in each direction, try all the fix tactics, repeat a few times, then flush with gear oil and refill? (Keeping in mind it isn't clear to me whether the problem is something mechanically sticking inside the actuator housing or inside the T-case itself.)

I doubt WD40 will damage any of the seals, etc, but my concern is more that it could get into places it won't then come out of easily (bearings?) and displace gear oil/grease that otherwise properly lubricates these components.

I would really like 4LO to work and to keep my hundreds of dollars. Also I don't want the T-case to fail in 5k miles because I filled it with something other than geal oil (cake and eat it, too). Keep in mind I realize this is a rather crazy idea.

Thanks in advance for the input.

 

[mrpurplepenguin]

When you loosened the actuator bolts and exercised it, did it suck in and protrude out as you worked the 4hi/4lo switch on/off? If it did, the actuator is working and the shaft into the transfer case is binding. If it didn't, the actuator is seized but the internals of the transfer case may be fine. Usually it's the actuator that seizes, I haven't heard a report of the actuator functioning but the 4lo shaft / engaging pawls being bound up (although that doesn't mean it hasn't happened). If the actuator is still seized, replacing the gear oil with WD40 or another penetrating lubricant probably won't do much good.

If the actuator functions and it's the shaft that's stuck, I don't have any clever ideas for you. WD40 or similar _might_ be fine to use inside the transfer case, but I can't advise you one way or the other there.

 

[chili]

Makes great sense. I hadn't thought of that. You are absolutely right: with the actuator housing bolts loosened, activating the CLD pushes the actuator housing away from the transfer case. Activating 4LO does not yield this result, so it must be stuck inside the actuator itself. Darn. I was really hoping I could solve another fault with trusty WD40. Back to repeating all the old tricks and hoping it changes. Thanks for the input.

 

[mrpurplepenguin]

Glad I could help shed some light on it, sorry it's still not working though.

You could try ***CAREFULLY*** opening up the actuator box (without removing it) and seeing if you can manually actuate the motor shafts, or maybe spray some lubricant in there to free things up. I can't overemphasize how careful you need to be though, some of the gears in there need to be in the correct orientation or the system no longer functions and you might end up stuck halfway in 4wd and unable to move the vehicle. I don't know if any gears will want to fall out when you open the cover, you'll need to do some research (see threads here and here). I DO know that to date, the guts haven't been documented very well and no one has figured out the gear timing if they get removed (well, no one has documented it at least), so if you do go that route take lots of pictures!

Finally, another option: leave it be. 4lo is hardly ever needed unless you're doing some pretty extreme stuff, for most of us 4hi with the diff locked is more than we'll ever need. It's definitely annoying that it doesn't work, but if you don't ever use it the cost to fix can be difficult to justify.

 

[chili]

UPDATE: Good news!!

Well this disgustingly hot and humid New England day yielded a fantastic result:

My 4LO STARTED WORKING!!!! :biggrin2::biggrin2::biggrin2::biggrin2:

I've only had the truck for about 6 weeks I was resigning myself to not having 4LO without doing a t-case teardown per the helpful link provided above. I hadn't tried 4LO in a week or so, and just gave it a shot while out in the dirt. Barely flashed once and went steady. I had a brief moment of 'oh sh** I hope it comes back OUT of 4LO' and it did, just as easily. I then had a grand old time changing between 2HI, 4HI, 4LO, diff lock, on steep hills in both directions (figured it might lube something up that was sticking) and even playing around with the downhill ascent control! It's about 93 out with 50% humidity, and prior to trying it, the truck was sitting, idling, for about 10 minutes. Must have gotten just hot enough.

Feels like I really have a 4Runner now! Fingers crossed that it keeps working in cooler weather, but now that I've gotten this far I'll be exercising it all the time. Yaaaaay! And thanks again to the forum members for all their excellent info.

 

[interputed]

I was going to suggest pouring about half a bottle of Seafoam in there, driving it for a few hundred miles, then doing a fluid change to 75w90 synthetic.

I bought my 4Runner with 94,000 miles on it, and it was very clear none of the fluids other than the motor oil had ever been changed. I had to change fluid in the rear diff 3x before it didn't immediately turn black. It's hard to believe people buy these things without ever doing any maintenance, or even using 4LO or the center lock... but it seems pretty common.

I'd change that fluid ASAP! But, don't bother with Seafoam since it came unstuck on its own. Also, never use Seafoam in the diffs as it can cause your seals to leak.

 

[Speedy123]

Another success story. I have tried to engage LO about 200 times this week since I bought my 03, beeping and no luck. Tonight tried again, heard a horrible God awful grinding noise, now works like a charm. Don't give up on your LO

 

[mustangpro]

When I was looking for a 4Runner last year I was shocked to find out the the Lexus GX470 has a true mechanical shifter to engage 4LO. I would have thought Lexus would've used the dial/button and the 4Runner would have the shifter. Go figure? The guy I bought it from had no clue what that shifter was for, which I'm sure most GX owners don't. He was in shock when I demonstrated it. But I have to admit I like the gear grinder shifter of the GX. I wonder if it could be adapted to a 4Runner??

 

[cpark_12]

I wonder if it could be adapted to a 4Runner??

I thought about this when my transfer case actuator was acting up. I would think it could be done fairly easy, but I would think you'd need the 4wd module from the Lexus as well as the transfer case. I priced the transfer case and they're expensive! The cheapest used one I could find was around $1500. If my actuator ever goes out, I'd seriously consider swapping in the GX470 transfer case though. I guess we'll see!

 

[interputed]

Somewhat unrelated, but what is 4LO even for? I've climbed up hills where I felt like I was in danger of flipping backwards with it in 4H in 1st gear with no difficulty. I guess for pulling things uphill?