4wd is very loud, has a hard time going back to 2wd.

[Shauncho]

Ok so I have this '99 4runner that I bought used and 4wd was seldom used, if ever, over the life of the vehicle. It engages in 4hi but when it does, it's pretty noisy. I've never owned a 4wd vehicle before so didn't know if this is standard. I figured I'd hear a little extra noise but not as much as I'm hearing. it's a noisy gear sound. can't quite tell where it's coming from. Also the steering is pretty jittery when in 4hi...little bumps in the road bounce me all over the place. I tried going into 4low once and it kinda grinded a little...eventually went into 4low but then was almost impossible to get back to 2wd so never tried it again because I didn't want to mess anything up.

Also when I am in 4hi and try to go back to 2wd, sometimes it doesn't engage. Yesterday, for instance, I kept trying to get it to go back to 2wd, it wouldn't get out of 4hi...then I had to do a uturn in a cul de sac and in the middle of the turn it finally switched back over. Did turning have anything to do with it going back or was it probably just a coincidence?

 

[Brian757]

Have you flushed and refilled your transfer case & differentials? At least to look at the fluid.

 

[Shauncho]

I have not yet. This was suggested to me on another forum as well and am planning on doing that soon to see the condition of the oil. I suspect this is what it's from but wanted to get people's input before i go out and start buying oil.

 

[Brian757]

I have not yet. This was suggested to me on another forum as well and am planning on doing that soon to see the condition of the oil. I suspect this is what it's from but wanted to get people's input before i go out and start buying oil.

I hear you. I'm not fond of throwing money at problems either. But its an easy procedure, and since you don't know how long it's been since those fluids have been changed, it doubles as a piece of mind moving forward.

This info should help in case you decide to tackle the idea...

This is for a synthetic conversion:
Transfer Case
1.1 Quarts - Amsoil Synthetic 75W-90

Front Differential
1.2 Quarts - Amsoil Synthetic 75W-90

Rear Differential
2.6 Quarts - Amsoil Synthetic 80W-90

 

[jgue467]

Yup, cuz of lack of use and old fluids. Change 'em and use the 4wd weekly. Mine makes absolutely no additional noise/sounds and steering is unaffected when in 4wd.

When i first got the rig 3 yrs ago it too would have 'trouble' engaging/disengaging (4 green tire lites and orange one in middle that represents the center diff would blink).

Not a coincidence on the turn. I too learned if you engage/disengage just before a right turn, it would immediately engage/disengage. After a few months of weekly 10 mile use, it now engages/disengages at will going straight or whatever direction.

I went with 85-140 for the rear since it really Hot in Texas.

Check your rear diff breather while you're at it - might save you rear axle seals in the process.

Also grease up the driveline, max 3 pumps on the slider.

Fluids are cheap compared to the cost of opening that 4wd unit up.

Luck! :banana:

 

[Shauncho]

I hear you. I'm not fond of throwing money at problems either. But its an easy procedure, and since you don't know how long it's been since those fluids have been changed, it doubles as a piece of mind moving forward.

This info should help in case you decide to tackle the idea...

This is for a synthetic conversion:
Transfer Case
1.1 Quarts - Amsoil Synthetic 75W-90

Front Differential
1.2 Quarts - Amsoil Synthetic 75W-90

Rear Differential
2.6 Quarts - Amsoil Synthetic 80W-90

Thank you very much for that info! I'll change the oils asap!

Yup, cuz of lack of use and old fluids. Change 'em and use the 4wd weekly. Mine makes absolutely no additional noise/sounds and steering is unaffected when in 4wd.

When i first got the rig 3 yrs ago it too would have 'trouble' engaging/disengaging (4 green tire lites and orange one in middle that represents the center diff would blink).

Not a coincidence on the turn. I too learned if you engage/disengage just before a right turn, it would immediately engage/disengage. After a few months of weekly 10 mile use, it now engages/disengages at will going straight or whatever direction.

I went with 85-140 for the rear since it really Hot in Texas.

Check your rear diff breather while you're at it - might save you rear axle seals in the process.

Also grease up the driveline, max 3 pumps on the slider.

Fluids are cheap compared to the cost of opening that 4wd unit up.

Luck! :banana:

And thank you also for your input! Much appreciated! I was planning on doing the rear diff breather mod anyway when I go to change the fluids.


Ok so question for both of you (or anyone else for that matter), lets say I wanted to try to flush out whatever old stuff I could. what's the recommended procedure for that? Just fill with new oil, run around for a while then drain and refill?

 

[Brian757]

Ok so question for both of you (or anyone else for that matter), lets say I wanted to try to flush out whatever old stuff I could. what's the recommended procedure for that? Just fill with new oil, run around for a while then drain and refill?

Here:
4Runners.org - Changing Your Front, Rear, Tranny & Transfer Case Fluids

The site is a little outdated or the OP lost his photo file location. But the text is useful, and no need to reinvent the wheel.

 

[jgue467]

Ok so question for both of you (or anyone else for that matter), lets say I wanted to try to flush out whatever old stuff I could. what's the recommended procedure for that? Just fill with new oil, run around for a while then drain and refill?

Good questions. Either that idea or maybe, just maybe put 2-3 ounces of seafoam in (says it for that purpose too on the can), drive a couple miles then drain? Maybe it will be just good enough with fresh fluids?

Anyone else have thoughts on a diff flush?

 

[Brian757]

Good questions. Either that idea or maybe, just maybe put 2-3 ounces of seafoam in (says it for that purpose too on the can), drive a couple miles then drain? Maybe it will be just good enough with fresh fluids?

Anyone else have thoughts on a diff flush?

[MENTION=101255]Shauncho[/MENTION]: I would see how much particulate is in the original fluid to see if you should do 2 cycles of fluid exchange. I would only do one change though. If you follow the steps in the aforementioned link, you should be fine. I would pull the diff covers before I would run two cycles of fluids. That way I could inspect the gears, ring & pinion and shafts.

Have you gotten underneath your truck to know whether or not the t-case or one/both of your differentials are leaking?

 

[Shauncho]

[MENTION=101255]Shauncho[/MENTION]: I would see how much particulate is in the original fluid to see if you should do 2 cycles of fluid exchange. I would only do one change though. If you follow the steps in the aforementioned link, you should be fine.

Have you gotten underneath your truck to know whether or not the t-case or one/both of your differentials are leaking?

No I haven't looked yet. didnt' see any puddles so didn't think to look. 2wd seems pretty smooth so I'm assuming the rear probably doesn't have any leaks however it wouldn't surprise me if the front had a leak.

Thanks again for all your help. when I have a chance to work on this I'll report back and let you guys know what I found.

 

[Brian757]

No I haven't looked yet. didnt' see any puddles so didn't think to look. 2wd seems pretty smooth so I'm assuming the rear probably doesn't have any leaks however it wouldn't surprise me if the front had a leak.

Thanks again for all your help. when I have a chance to work on this I'll report back and let you guys know what I found.

Anytime. Keep in mind you're on T4R.org. It's what we do.

 

[Shauncho]

ok so I finally got under there and cracked open the fill plug on the transfer case and it was completely full, dripping from the top, and was a very light amber color. almost like a lager or light red ale. So i'm thinking that may not be my issue. What are your thoughts?

unfortunately I don't have the right size tool for the front diff drain valve however upon inspection I see a lot of dark oil all over the side of the front diff. like oil was spilled and coated with dirt as old leaks look...need to look closer to see if it looks like it came from the diff or the engine.

 

[BrianSD_42]

Were you driving on pavement? (This is a serious question dammit)

 

[BrianSD_42]

I tried going into 4low once and it kinda grinded a little...eventually went into 4low but then was almost impossible to get back to 2wd so never tried it again because I didn't want to mess anything up.

I'm willing to bet that you did not have the vehicle stopped and in N when switching LO/HI , HI/LO.

That grinding sound is your transfer case killing itself because you did not stop the car completely.

And the "noise you mention" is likely a popping sound that happens especially hard when going in and out of 4HI to/from 4WD when on pavement and even sometimes on gravel. If you are engaging it while on pavement stop and never do it again, wait until you are on dirt, snow, ice, mud. Even wet pavement is still bad.

If everything I said doesn't apply to you then it is something else but still follow this advice!

 

[Shauncho]

Were you driving on pavement? (This is a serious question dammit)

Yes I was...see, that's how new I am to 4wd. I didn't know you're not supposed to drive on normal pavement in 4wd.

I'm willing to bet that you did not have the vehicle stopped and in N when switching LO/HI , HI/LO.

That grinding sound is your transfer case killing itself because you did not stop the car completely.

And the "noise you mention" is likely a popping sound that happens especially hard when going in and out of 4HI to/from 4WD when on pavement and even sometimes on gravel. If you are engaging it while on pavement stop and never do it again, wait until you are on dirt, snow, ice, mud. Even wet pavement is still bad.

If everything I said doesn't apply to you then it is something else but still follow this advice!

I did try it while the vehicle was stopped but I didn't put it into N until the second attempt. ok so just so I make sure I got it right:

• Don't engage 4wd on pavement
• Only engage 4low when the vehicle is stopped and in Neutral.

Anything else?

 

[BrianSD_42]

When you are not on pavement ..

In drive and moving less than 40 MPH you can click the electronic engage 4WD button (96-99) assuming it's an automatic.

Now you will be in 4HI, keep driving.

Wait now you want to go to 4LO? Ok do this.

Stop the vehicle completely. Completely!
Put it in N.
Move the lever from 4HI to 4LO
Put it in Drive.

Drive the car.

Going back to 4HI then 2WD is the exact same process but backwards.

If you do this you should not hear any grinding (aka your truck killing itself)

Glad I could help solve the case.

 

[Shauncho]

When you are not on pavement ..

In drive and moving less than 40 MPH you can click the electronic engage 4WD button (96-99) assuming it's an automatic.

Now you will be in 4HI, keep driving.

Wait now you want to go to 4LO? Ok do this.

Stop the vehicle completely. Completely!
Put it in N.
Move the lever from 4HI to 4LO
Put it in Drive.

Drive the car.

Going back to 4HI then 2WD is the exact same process but backwards.

If you do this you should not hear any grinding (aka your truck killing itself)

Glad I could help solve the case.

OK cool. thanks for the info! Actually, mine doesn't have an electronic engage button, it's a stick next to the transmission auto stick but I take it it's still the same process either way, right?

 

[BrianSD_42]

If you don't have an electronic button on that 2nd stick then perhaps you should try stopping the car first before going into 4HI. I'm really not sure about you setup but that is what I would try.

 

[AZ_Trails]

If you don't have an electronic button on that 2nd stick then perhaps you should try stopping the car first before going into 4HI. I'm really not sure about you setup but that is what I would try.

If you have the standard J-shifter, you should be able to to switch into 4H while moving. I believe you can do this up to 55 mph. Definitely nothing wrong with stopping first if you can tho. But to get into 4L definitely need to be stopped, with either the clutch in (for us manual guys) or the transmission in N.

 

[Shauncho]

If you don't have an electronic button on that 2nd stick then perhaps you should try stopping the car first before going into 4HI. I'm really not sure about you setup but that is what I would try.

If you have the standard J-shifter, you should be able to to switch into 4H while moving. I believe you can do this up to 55 mph. Definitely nothing wrong with stopping first if you can tho. But to get into 4L definitely need to be stopped, with either the clutch in (for us manual guys) or the transmission in N.

Awesome guys! Thanks for all the help!

Just for my knowledge, why is driving on pavement in 4wd bad for it?

EDIT: never mind...found this: http://www.howstuffworks.com/four-wheel-drive.htm

but feel free to chime in anyway.

Oh, also forgot to ask about the second part of my OP...changing back to 2wd from 4hi. It didn't seem to want to go back. I'd tried everything, stop, rolling slowing (<5mph), and it didn't seem to want to change back to 2wd until I was making a uturn. What's up with that?