Did I Possibly Damage My 4WD System?

[BlueRunner428]

So I had a bit of a boo-boo in the 4Runner coming home last night (I work night shift). Decided since I was on straight road and the manual recommends driving with the 4WD engaged for at least ten miles each month, I'd engage it. Since I have never used 4Lo before and wanted to try out the Multi-Terrain Select, I stopped (road was deserted), put the vehicle n neutral, put into 4Lo, then engaged the Multi-Terrain System in one of the modes requiring 4Lo and drove straight for a very short distance and at very slow speed. Satisfied that it was in fact engaged, I then stopped again, put it in Neutral, turned off the Multi-Terrain, and disengaged the 4WD. However I disengaged it completely when I meant to just put it into 4Hi. So I started driving again and figured I'd just put it back into 4Hi, so I pulled the shifter (or started to) and heard and felt this horrible loud grinding sound. Only heard it for a split second as I immediately let go of the shifter. I drove a short distance, then stopped and shifted it into 4Hi and it engaged fine then. I drove some more and shifted while moving into 2WD then back into 4Hi without any problem.

Anyone know what happened? I am guessing it was something related to it just having been in 4Lo and maybe something hadn't quite disengaged yet or something (I know if you shift into 4Hi it can sometimes take a second to "catch." I am guessing going from 4Lo to 2WD then suddenly back into 4Hi caused the mechanism to ground as something was still in the way). I may have forgotten to put it into Neutral again before shifting out of 4Lo but believe I did.

Am wondering if I could have damaged anything? It was only for a split second and the 4WD light comes on fine, so hoping it is okay.

 

[honda250xtitan]

youre fine.

 

[RootedWanderer]

You heard the multi track disengaging. It makes all kinds of noises when active. You're fine.

So I had a bit of a boo-boo in the 4Runner coming home last night (I work night shift). Decided since I was on straight road and the manual recommends driving with the 4WD engaged for at least ten miles each month, I'd engage it. Since I have never used 4Lo before and wanted to try out the Multi-Terrain Select, I stopped (road was deserted), put the vehicle n neutral, put into 4Lo, then engaged the Multi-Terrain System in one of the modes requiring 4Lo and drove straight for a very short distance and at very slow speed. Satisfied that it was in fact engaged, I then stopped again, put it in Neutral, turned off the Multi-Terrain, and disengaged the 4WD. However I disengaged it completely when I meant to just put it into 4Hi. So I started driving again and figured I'd just put it back into 4Hi, so I pulled the shifter (or started to) and heard and felt this horrible loud grinding sound. Only heard it for a split second as I immediately let go of the shifter. I drove a short distance, then stopped and shifted it into 4Hi and it engaged fine then. I drove some more and shifted while moving into 2WD then back into 4Hi without any problem.

Anyone know what happened? I am guessing it was something related to it just having been in 4Lo and maybe something hadn't quite disengaged yet or something (I know if you shift into 4Hi it can sometimes take a second to "catch." I am guessing going from 4Lo to 2WD then suddenly back into 4Hi caused the mechanism to ground as something was still in the way). I may have forgotten to put it into Neutral again before shifting out of 4Lo but believe I did.

Am wondering if I could have damaged anything? It was only for a split second and the 4WD light comes on fine, so hoping it is okay.

 

[Forgetful]

Did you leave the 4wd shifter in neutral for a little bit before shifting it? It'll grind if so, kinda odd but the best way to shift between 4hi and lol is fast, no hanging out in neutral or it'll grind.

 

[orcking]

Did you leave the 4wd shifter in neutral for a little bit before shifting it? It'll grind if so, kinda odd but the best way to shift between 4hi and lol is fast, no hanging out in neutral or it'll grind.

Actually, when engaging and disengaging the 4LOW, you have to give it some time in neutral, the light should be blinking and then when it is off, shift out.
You are ok, do not worry about it.

 

[Forgetful]

Actually, when engaging and disengaging the 4LOW, you have to give it some time in neutral, the light should be blinking and then when it is off, shift out.
You are ok, do not worry about it.

You talking about the TRD manual shifter or the electric dial on SR5? Manual shifter definitely doesn't like hanging in neutral since the transmissions output somehow spins the input shaft to the transfer case and then you'll grind.

 

[baldrik78]

You didn't damage anything. Occasionally getting that grinding is normal - sometimes the gears struggle to engage. When I get it, I typically push it back into the 2hi position, give it a second and then try putting it into 4hi again. Also, make sure you are moving when you got from 2hi to 4hi or viceversa. The only thing you want to be stopped for is moving in or out 4lo.

 

[Grug556]

I put mine in locked 4hi alot (limited) mainly just on straights to keep system moving every so often. I avoid any turns or stuff like that on high friction dry pavement. I have found that going into low I need to wait alittle bit for flashing to stop then it goes in. Takes maybe 2 seconds or so i think. SOmetimes I get abit of noise..other times none.

 

[Captain Spalding]

I put mine in locked 4hi alot (limited) mainly just on straights to keep system moving every so often. I avoid any turns or stuff like that on high friction dry pavement. I have found that going into low I need to wait alittle bit for flashing to stop then it goes in. Takes maybe 2 seconds or so i think. SOmetimes I get abit of noise..other times none.

What does locking the center differential do for you in terms of exercising the drive train in a vehicle with full-time 4WD? I thought the manual’s advice to drive 10 miles per month in 4WD only applied to the part time models.

 

[Grug556]

What does locking the center differential do for you in terms of exercising the drive train in a vehicle with full-time 4WD? I thought the manual’s advice to drive 10 miles per month in 4WD only applied to the part time models.

You know...im not really sure. Perhaps it does nothing. I just like seeing the locked icon appear on the dash, makes me feel like im driving a tank.. Perhaps it gives the transfer case some kind of work out via solenoids? :bounce:

Its the same as putting it in low every few weeks, just keeps things active rather than letting them sit and rot. ainkiller:

Locking the center sure makes driving really fun in deep heavy snow, turns now become sideways plows! I like locking the center in deep gravel and other junk when i go up north, but thats about it.

I also like the downhill assist button... that green hill icon is funny looking...op2:

 

[Whippersnapper02]

So I had a bit of a boo-boo in the 4Runner coming home last night (I work night shift). Decided since I was on straight road and the manual recommends driving with the 4WD engaged for at least ten miles each month, I'd engage it. Since I have never used 4Lo before and wanted to try out the Multi-Terrain Select, I stopped (road was deserted), put the vehicle n neutral, put into 4Lo, then engaged the Multi-Terrain System in one of the modes requiring 4Lo and drove straight for a very short distance and at very slow speed. Satisfied that it was in fact engaged, I then stopped again, put it in Neutral, turned off the Multi-Terrain, and disengaged the 4WD. However I disengaged it completely when I meant to just put it into 4Hi. So I started driving again and figured I'd just put it back into 4Hi, so I pulled the shifter (or started to) and heard and felt this horrible loud grinding sound. Only heard it for a split second as I immediately let go of the shifter. I drove a short distance, then stopped and shifted it into 4Hi and it engaged fine then. I drove some more and shifted while moving into 2WD then back into 4Hi without any problem.

Anyone know what happened? I am guessing it was something related to it just having been in 4Lo and maybe something hadn't quite disengaged yet or something (I know if you shift into 4Hi it can sometimes take a second to "catch." I am guessing going from 4Lo to 2WD then suddenly back into 4Hi caused the mechanism to ground as something was still in the way). I may have forgotten to put it into Neutral again before shifting out of 4Lo but believe I did.

Am wondering if I could have damaged anything? It was only for a split second and the 4WD light comes on fine, so hoping it is okay.

It's fine.

What does locking the center differential do for you in terms of exercising the drive train in a vehicle with full-time 4WD? I thought the manual’s advice to drive 10 miles per month in 4WD only applied to the part time models.

Exercises the center lock actuator.

 

[Salvo Jimmy]

It's fine.



Exercises the center lock actuator.

And puts it in true 4WD where the 4 wheels are locked together as opposed to AWD where they are not locked together and you are ok on pavement in tight turns in AWD. This is the system on Limited in 4HI. 4HI on others are all 4 wheels are locked together, hence why manual says don’t use on pavement. But you can if don’t make tight turns.

 

[DAW89446]

Getting your ten monthly miles in 4x4 is easy if you have maintained dirt roads around your area. I live in an area where dirt roads outnumber paved ones, though my road is paved. Any time I go down a dirt road, I put my ‘18 SR5 in 4HI just to keep the shifting mechanisms limber and the greases and oils doing their job. And with winter weather here, the truck is in 4WD more than 2WD anyways due to snow, ice and mud.

If you have the J gate lever transfer case shifter (TRD models) grinding just happens occasionally. No worries. My SR5 has the electronic dial shifter, but before my T4R I had a ‘02 Tacoma TRD Off Road. I’d grind gears now and then. The same with all my previous 4x4 trucks all the way back to my 1970 Ford F250 4x4. The Tacoma went to my grandson when I got the T4R and it is still going strong at over 225,000 miles with no repairs.

 

[BlueRunner428]

And puts it in true 4WD where the 4 wheels are locked together as opposed to AWD where they are not locked together and you are ok on pavement in tight turns in AWD. This is the system on Limited in 4HI. 4HI on others are all 4 wheels are locked together, hence why manual says don’t use on pavement. But you can if don’t make tight turns.

Well neither system literally locks all four wheels together, what happens is there are two drive shafts, one going to the rear axle and one to the front axle. With the part-time system, you normally operate in 2WD and thus have just the rear driveshaft turning and delivering power to the rear axle. When 4Hi is engaged, the transfer case connects the front driveshaft and rear driveshsfts together via a chain so they both rotate together. Whereas with the full-time system on the Limited, the front and rear driveshafts are always engaged, but there is a center differential separating them that allows them to rotate independently of one another. Locking this differential creates the same effect as the part-time system and in both cases, since the driveshafts are locked together, it is bad to be on bare pavement if making turns as it will strain the drivetrain components. However, both axles have differentials that allow each wheel to still turn independently of the opposite wheel on that axle, so all four wheels aren't per se locked together. To lock them, you'd need locking differentials. Off-Road trim 4Runners come with a rear locker and all 4Runners have the A-trac system which simulates lockers via the braking system.

AWD generally means an active system that actively transfers torque to different wheels depending on how much grip each wheel has. Full-time 4WD is different from AWD. Automatic 4WD is also not the same as AWD.

The 4Runner is very unique in that it sort of has a combination 4WD/AWD system as the A-trac operates like a form of AWD system, except a locked center differential or conventional transfer case locks both axles together.

 

[BlueRunner428]

Thank you for all of the information everyone

 

[BlueRunner428]

Getting your ten monthly miles in 4x4 is easy if you have maintained dirt roads around your area. I live in an area where dirt roads outnumber paved ones, though my road is paved. Any time I go down a dirt road, I put my ‘18 SR5 in 4HI just to keep the shifting mechanisms limber and the greases and oils doing their job. And with winter weather here, the truck is in 4WD more than 2WD anyways due to snow, ice and mud.

If you have the J gate lever transfer case shifter (TRD models) grinding just happens occasionally. No worries. My SR5 has the electronic dial shifter, but before my T4R I had a ‘02 Tacoma TRD Off Road. I’d grind gears now and then. The same with all my previous 4x4 trucks all the way back to my 1970 Ford F250 4x4. The Tacoma went to my grandson when I got the T4R and it is still going strong at over 225,000 miles with no repairs.

So gear grinding doesn't damage the gears?

 

[Salvo Jimmy]

Well neither system literally locks all four wheels together, what happens is there are two drive shafts, one going to the rear axle and one to the front axle. With the part-time system, you normally operate in 2WD and thus have just the rear driveshaft turning and delivering power to the rear axle. When 4Hi is engaged, the transfer case connects the front driveshaft and rear driveshsfts together via a chain so they both rotate together. Whereas with the full-time system on the Limited, the front and rear driveshafts are always engaged, but there is a center differential separating them that allows them to rotate independently of one another. Locking this differential creates the same effect as the part-time system and in both cases, since the driveshafts are locked together, it is bad to be on bare pavement if making turns as it will strain the drivetrain components. However, both axles have differentials that allow each wheel to still turn independently of the opposite wheel on that axle, so all four wheels aren't per se locked together. To lock them, you'd need locking differentials. Off-Road trim 4Runners come with a rear locker and all 4Runners have the A-trac system which simulates lockers via the braking system.

AWD generally means an active system that actively transfers torque to different wheels depending on how much grip each wheel has. Full-time 4WD is different from AWD. Automatic 4WD is also not the same as AWD.

The 4Runner is very unique in that it sort of has a combination 4WD/AWD system as the A-trac operates like a form of AWD system, except a locked center differential or conventional transfer case locks both axles together.

True dat, was just trying to keep it simple on difference and why bad on pavement

 

[Whippersnapper02]

So gear grinding doesn't damage the gears?

If you're trying to make a song out of it, yes there will eventually be some damage. A quick grind will not cause any real damage.

 

[Buz06]

I don't think there are any syncro's in there so things will always be a little crunchy. I'm also pretty certain you won't hurt anything unless you are really being abusive. I'm fortunate that the local dirt road I use for monthly 4 lo is a slight incline and sometimes it helps things mesh when I slowly roll a little backwards in neutral waiting for the blinking to stop.
By the way congratulations on actually reading the owner's manual. Seems like a lot of people do not and they really are very useful.

 

[Bmnorm2]

Hopefully someone with more knowledge of our Transfer Case will step in...

In the meantime, I think the Hi and Lo gears in the transfer Case are a dog ring type and not synchromesh. So, the system can't synchronize the two speeds and will "grind" if not matched. This is why you need to come to a stop and be in neutral to shift from 4Hi to 4Lo and vice versa.

Either way whether our Transfer case is dog ring or synchromesh, the "grinding" isn't the actual gears, it's the dog teeth on the synchro. These teeth are very robust and made to withstand many screw ups.

So, you are fine, just try not to do it again and again.

Dog ring gearbox explained!