PLEASE HELP, grinding when going into 4L

[Erkelbot]

Ever drive a manual and grind the gears? Same sort of thing. Do it a couple times and it shouldn't be a big deal. Do it often and you're going to wear the gears out.

Sounds logical. I guess the only difference would be the amount of torque you have going through the gears. For instance, power shifting an 87 accord with a 2.2L VTEC probably isn't as much of a gamble as flipping into 4L.

Phew, that's a load of my mind... Thanks guys!

 

[m85476585]

I don't understand why anything is moving in the transfer case if the transmission is in neutral? Since the wheels are stopped, the output side of the transfer case is stopped, which stops the input side while it's in neutral in 4H. The transmission is between the engine and transfer case, right?

Same for going from 2H to 4H while stopped in neutral. Nothing is moving in the drivetrain, so what could grind (I think someone in another thread had grinding in this situation)? Even in gear if you are stopped, the input shaft to the transfer case shouldn't be moving as long as you don't go through N on the transfer case, though there would be some force on it.

I would just like to understand how it work, because it doesn't make sense to me right now.

 

[nevada]

I don't understand why anything is moving in the transfer case if the transmission is in neutral? Since the wheels are stopped, the output side of the transfer case is stopped, which stops the input side while it's in neutral in 4H. The transmission is between the engine and transfer case, right?

Same for going from 2H to 4H while stopped in neutral. Nothing is moving in the drivetrain, so what could grind (I think someone in another thread had grinding in this situation)? Even in gear if you are stopped, the input shaft to the transfer case shouldn't be moving as long as you don't go through N on the transfer case, though there would be some force on it.

I would just like to understand how it work, because it doesn't make sense to me right now.

I would guess automatic transmission are less susceptible, but have you ever had a manual rig up on jackstands and started it in neutral? often times the tires will turn. just the fluid will cause parts to move. also, with the manual, the input shaft is being spun by the engine. again, i know the auto doesn't work that way, was just explaining...

also, I don't know about 4runners, but i once drove a Chrysler, that even when in PARK, if you revved the engine, it would move the car backwards slightly(just enough to notice movement). apparently it was bleeding a bit of pressure across to reverse somehow...

 

[Mark4runnar]

anti grinding

if it bugs you to hear / feel the grinding---turn the engine off and follow the instructions.
weak answer but my brain hates grinding
:flame:

 

[Swarty]

No, you are correct, that is how it works.

I would guess automatic transmission are less susceptible, but have you ever had a manual rig up on jackstands and started it in neutral? often times the tires will turn. just the fluid will cause parts to move. also, with the manual, the input shaft is being spun by the engine. again, i know the auto doesn't work that way, was just explaining...

You are right until you say the auto doesn't work that way...
The auto is still a planetary gear system with friction and viscous drag between the parts. The torque converter under very light load will act pretty much like a solid input shaft and the rest of the transmission is going to want to spin with that shaft. The longer you hang out with the trans axle in neutral the faster the drive side will spin (well, up to a limit) and the more grinding you probably will experience.