A few days ago i decided to drive my 99 4runner in 4wd because it spends about 95% of its life in 2wd and its good to keep things working by using them. The mode i used was H4 (activated with the side button). Anyway, i initially noticed that the car had a good amount more driveline noise than in 2wd. I mean, the radio has to be off, and the air at a low setting to hear it, but its definately noticeable. It has about 83K miles on her and the only thing i have done is basic oil changes (synthetic), oil filter, pcv valve, air filter, etc. I plan on doing a more in depth service on it VERY soon (waterpump, belts, hoses, etc.). But is there anything i can do to help fix this specific problem? Lubing things up, changing bearings or bushings, or whatever the case may be, please give me your advice. Oh, and i did try to search, just didnt really find what i was looking for. Thanks in advance...

 

Does it have the Multi-Mode 4WD (w/ center diff)? driveline noise can be heard if it does not have a center diff and 4wd is engaged on dry pavement.

 

Hopefully you don't do that on dry pavement. Driveline noise will increase in 4wd anyway, but not by a lot. This is because much of the stuff that is only designed for part time use doesn't get muc NVH engineering. But - on dry pavement you'd get all sorts of noises - some really wierd ones. The loudest and wierdest would be your transfer case and driveshafts complaining and threatening to give up....

 

If you haven't done so already, I'd suggest you get under the truck and lube the driveshafts. Torque the bolts also.

 

4 Sure... :pat:

 

Very good point. If it's been unused for a long time, the front driveshaft and u-joints might not be lubed properly.

Also, mine got noisy at one time, and eventually I had the front driveshaft checked and it was bent. Considering how I used that 4Runner, it was no surprise. They straightened it and instant quiet!

A bad CV can make noise and vibration too.

But if it's not vibrating and you can only hear it with the radio off etc. then it's probably just normal. Lube it anyway. Never hurts.

 

is the noise coming from the front of the drivetrain? the center? the rear? can you tell? i think the origin of the sound should be considered.

also, what kind of noise is it exactly?

 

The noise sounds like metal clatter; i could be wrong but i beleive its coming from the center of the vehicle.

About using 4wd on dry pavement.... im using the H4 mode (it has center differential). This mode is safe for paved surfaces....atleast thats what the manual says. H4 mode is activated by just pressing the little button thats says 4WD on the side of the selector.

And finally, about lubing it up, i got under the truck yesterday with my grease gun and greased 2 zerks, but after i noticed that one of them just wouldnt stop taking grease, i stopped. I probably pumped more than 10 times and it kept taking. What should i do to make sure i didnt pump too much? Should i take off the zerk? Can i pump grease into the rest of the zerks without worrying about over-greasing? Thanks guys...

 

I really don't think you can over-grease. The excess will squeeze past the seals. I'd pump until you see old grease followed by the new.

 

The ones for u-joint and ball joints and stuff will ooze the old stuff out when you squirt the new stuff in. The one for the driveshaft slip joint is different - it will take grease seemingly forever. This one can definitely be overdone - if you fill up the slip joint with grease then when the driveshaft needs to shorten (like if you hit a bump) it can bend the driveshaft. 10 pumps should be fine though.

 

Just to be on the safe side, should i try taking off the zerk to see if any excess will come out, or maybe try to push in the little ball in the zerk?

Aside from slip joints, the rest can be greased normally correct?

Sorry for all the questions... im just hoping i didnt cause any damage.

Thanks!

 

yea, you can't overgrease, spar. just get it the h*ll done with the greasing, and forget the manual: 2H=Pavement, highway, 4H=Dry-dirt off-roading(NO PAVEMENT), 4L=Mud!!

uhh... also, i dont mean to be weird or anything, but check/tighten up all shields or any other underbody protection. it could possibly be as simple as that, so id give it a try.