95.5-2004 Tacomas & 96-2002 4Runners 4th gen pickups and 3rd gen 4Runners

Why would the rear wheel turn when gear is in neutral?

Thread Tools
 
Search this Thread
 
Old 10-01-2005 | 08:55 PM
  #1  
98arrunner's Avatar
Thread Starter
Registered User
 
Joined: Oct 2005
Posts: 11
Likes: 0
Why would the rear wheel turn when gear is in neutral?

Hi All,

I jacked up the rear axle for brake shoe replacement, and noticed that when I turn on the engine, with gear in neutral, the two wheels turns slowly (probably 2 revs per min). If i step on the gas (gear still in neutral), they turn a little faster, but slower than if in gear.

Why would the wheels (propeller shaft) turn when the gear is in neutral?

I have 98 4runner, v6, 4wd, 5spd, no mods.

Thanks in advance.
Old 10-01-2005 | 09:13 PM
  #2  
mike_d's Avatar
Registered User
 
Joined: Aug 2003
Posts: 613
Likes: 0
From: Mountains outside of Boulder
there's probably enough drag caused by the gear oil that tranfers just enough torque through the transmission to turn the wheels slowly.
Old 10-01-2005 | 09:21 PM
  #3  
TechWrench's Avatar
Registered User
 
Joined: Aug 2003
Posts: 513
Likes: 0
From: Glenville, NY
Originally Posted by mike_d
there's probably enough drag caused by the gear oil that tranfers just enough torque through the transmission to turn the wheels slowly.
That is exactly what is happening. You can grab the drive shaft, and it will stop, but the gear oil in the trans will provide enough 'drive' between the main and countershafts to turn the output shaft if there is very little resistance in the drive line.
Old 10-02-2005 | 10:33 AM
  #4  
kyle_22r's Avatar
Registered User
 
Joined: Mar 2003
Posts: 3,981
Likes: 4
From: Lacey, WA
kind of like the same idea behind a torque converter in an auto tranny or the fan clutch on the motor.
Old 10-02-2005 | 11:00 AM
  #5  
WATRD's Avatar
Contributing Member
 
Joined: Oct 2002
Posts: 5,089
Likes: 0
From: Duvall, WA
Ah... a beautiful lesson in fluid dynamics. What a great way to start a Sunday!
Old 10-02-2005 | 12:24 PM
  #6  
TechWrench's Avatar
Registered User
 
Joined: Aug 2003
Posts: 513
Likes: 0
From: Glenville, NY
Originally Posted by kyle_22r
kind of like the same idea behind a torque converter in an auto tranny or the fan clutch on the motor.
In a very abstract way, I suppose. The torque converter and fan clutch are specifically designed to provide a fluid coupling in a 'drive' line. What is happening in the manual trans is more like an undocumented feature.

Years ago, I had a '79 Chevy K10 with the old 4 speed manual with the 'granny' 1st gear. Where I usually parked at my home was on level ground, so I didn't normally set the parking brake. I learned the gear oil drive lesson very well when I left it idling one VERY COLD morning (about 15 below) before I went to work. I had started it to warm it up, and went back in to get my road coffee. When I came out, the truck was gone..........
I found it on the front lawn next door. The 90 weight was so stiff, it 'drove'
the truck about 80 feet until it decided to stop on its own. Used the parking brake a lot more after that
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Gamble_STi
86-95 Trucks & 4Runners
7
07-01-2015 01:51 PM
cchinny
General Electrical & Lighting Related Topics
6
06-25-2015 09:11 PM
Mr.Black
86-95 Trucks & 4Runners
3
06-21-2015 11:17 AM
AustinTaco
84-85 Trucks & 4Runners
4
06-21-2015 10:54 AM
dlotoy4runner
95.5-2004 Tacomas & 96-2002 4Runners
7
07-03-2002 04:42 AM




All times are GMT -8. The time now is 02:36 AM.