[Maximillian]

Hello all,

I am a relatively new owner of a certified used 2006 4WD V6 SR5 with roughly 58K miles on it. The truck is in great condition, never been off-road (as far anyone can tell) and generally very well maintained and cared for. A few days ago I engaged 4HI, 4LO and unfortunately locked the center diff to see if everything works. Everything seemed to go fine, although there was an awkward feel when the center diff lock was on.

I did this on dry pavement (I now know that this is stupid) for a mile or two, going at very low speeds (less than 15-20 mph). I also took some 90 degree turns slowly.

Nothing seems to have broken or so I hope. I read later that what I did is a recipe for disaster. I am worried that some stress/damage may have already happened to my drivetrain, despite the absence of "symptoms". Should I check it with a mechanic? My truck is under extended warranty until 2012/100K miles. I would hate to take it to the delarship, tell them about what I did and then invalidating my warranty if (god forbid) somethin happens down the road...

Would I be able to tell if I caused any damage? Could the stress on the drivetrain from my brilliant idea cause problems in the future? Any advice would be greatly appreciated.

Thanks.

[XJeepguy]

Probably didnt do any damage but slap yourself across the head and dont do that again !!!
Toy's are pretty tough !

[Maximillian]

(I originally put this in the Maintenance section; I am not sure if it was the right place; apologies)

Hello all,

I am a relatively new owner of a certified used 2006 4WD V6 SR5 with roughly 58K miles on it. The truck is in great condition, never been off-road (as far anyone can tell) and generally very well maintained and cared for. A few days ago I engaged 4HI, 4LO and unfortunately locked the center diff to see if everything works. Everything seemed to go fine, although there was an awkward feel when the center diff lock was on.

I did this on dry pavement (I now know that this is stupid) for a mile or two, going at very low speeds (less than 15-20 mph). I also took some 90 degree turns slowly.

Nothing seems to have broken or so I hope. I read later that what I did is a recipe for disaster. I am worried that some stress/damage may have already happened to my drivetrain, despite the absence of "symptoms". Should I check it with a mechanic? My truck is under extended warranty until 2012/100K miles. I would hate to take it to the delarship, tell them about what I did and then invalidating my warranty if (god forbid) somethin happens down the road...

Would I be able to tell if I caused any damage? Could the stress on the drivetrain from my brilliant idea cause problems in the future? Any advice would be greatly appreciated.

Thanks.

[CJ3Flyr]

Originally Posted by XJeepguy

Probably didnt do any damage but slap yourself across the head and dont do that again !!!
Toy's are pretty tough !

x2

I would go one step further...
It's a good idea to cycle the modes periodically and accrue a few miles in 4hi each month. When the V6 models switches from 2wd to 4wd the diff lock engages for the transition and gets it's exercise. IMHO there's no need to exercise the diff lock beyond that. The V8 guys should do a brief lock/unlock periodically (and a 4lo transition). The V8 T4R's are always in 4wd so they don't have that 'built-in' diff lock actuator exercise.

You're fine...

[M1911]

I doubt you've caused any damage. Just don't do that again. 4Hi was fine. 4Lo was fine. It was locking the diff that you shouldn't have done.

The reason for that "awkward feel" while the center diff was locked is that locking the center diff causes the front and rear driveshaft to rotate at the same speed. When you go around a corner, the rear steps in, so the rear diff takes a shorter distance around the corner than the front diff. Since locked diff prevents the front and rear driveshafts from turning at different speeds, the tires try to scrub and you load up the drivetrain.

[Maximillian]

Point taken =>

I understand. I initially did it to check that they work. I do try to put a few miles in HI4 from time to time, since I read somewhere that you need it to lub the front differential. I doubt that the first owner ever did it.

When I found out about the dangers of locking the center diff on hard surfaces with lots of traction... let say I was scared #$%*less... I babysit this truck and I would hate to damage it this way.

So the general consensus would be that no damage or premature failures due to stress are expected?

I will go for the 60K maintenance soon. I think they are going to check fluids on all differentials anyway. Would it hurt to ask them to check the drivetrain in some detail?

[CJ3Flyr]

Originally Posted by Maximillian

Point taken =>

I understand. I initially did it to check that they work. I do try to put a few miles in HI4 from time to time, since I read somewhere that you need it to lub the front differential. I doubt that the first owner ever did it.

When I found out about the dangers of locking the center diff on hard surfaces with lots of traction... let say I was scared #$%*less... I babysit this truck and I would hate to damage it this way. There are some vehicles where it could be an issue. If this 4Runner isn't on absolutely huge tires the strong, reliable drivetrain will handle your minor slip-up with no complaints.

So the general consensus would be that no damage or premature failures due to stress are expected? Correct, you're fine. If it breaks down the road it wasn't because of your short, gentle drive with the diff locked.

I will go for the 60K maintenance soon. I think they are going to check fluids on all differentials anyway. Would it hurt to ask them to check the drivetrain in some detail? No 'extra' inspection required. Normally the 60k will involve fresh fluid for the axles and t-case. See this thread for more: http://www.toyota-4runner.org/mainte...se-fluids.html

[Carl_G]

"premature failure due to stress" wow. That's how I feel at times!

[Will_4R]

What you did shouldn't weaken anything. If you broke or damaged anything you would know it immediately. Locking the diff on dry pavement (when you have good traction) isn't recommended, nor a good idea, but probably harmless at low speed especially if you avoid tight turns.

[rockwall]

I agree that any damage would be very likely to be felt immediately. I suggest that you (and all new owners) should read the owner's manual completely prior to trying out any functions. If you are new to a 4 wheel drive vehicle, there are some specific do's and don'ts.

[Shanesteeze]

the owners manual says to drive 10 miles a month in 4wd.
first post baby, everyone on this site is amazing. so much stuff i wanna do to my t4r my head gonna explode!!!

[Jed]

Just for the record, you could have put your 4Runner in 4wd hi or low and locked the center diff on dry pavement as long as you avoid turning. Going straight will cause no damage whatsoever. It's really only driveline binding you're trying to avoid when it comes to locking up the center differential.