Rear wheels underpower while in neutral in a manual???

Leadfooted · 07-22-2017, 11:59 PM

So I finished up my diff bushing change and got her put all back together and while still up on jack stands i go to do an exhaust leak test. Start up in neutral and let off the clutch and the wheels start spinning? Bad enough you could feel it shake when you hit the brake. If i hit the gas it would flash the slip light and cut the gas. So i finished up the exhaust leak test by pushing the clutch in so it didn't spin the wheels. Dropped the car down and did a test drive seems fine. Any ideas drove manuals my whole life never ran in to this before but never really started a car in the air. Thanks

BGTV8 · 07-23-2017, 02:44 AM

You have some drag inside the gearbox ..........

Friction in the the main shaft bearing (which sits inside a hollow in the input shaft) is the root cause.

Will be worst when the gearbox oil is cold and viscous.

Nothing to worry about

07-22-2017, 11:59 PM	#1 (permalink)
Leadfooted Base Member Join Date: Mar 2016 Location: Greenville S.C. Age: 46 Posts: 76 Drives: 14' nismo gm 6mt Rep Power: 9	Rear wheels underpower while in neutral in a manual??? So I finished up my diff bushing change and got her put all back together and while still up on jack stands i go to do an exhaust leak test. Start up in neutral and let off the clutch and the wheels start spinning? Bad enough you could feel it shake when you hit the brake. If i hit the gas it would flash the slip light and cut the gas. So i finished up the exhaust leak test by pushing the clutch in so it didn't spin the wheels. Dropped the car down and did a test drive seems fine. Any ideas drove manuals my whole life never ran in to this before but never really started a car in the air. Thanks

07-23-2017, 02:44 AM	#2 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,514 Drives: 09 Nissan 370Z M6 Rep Power: 39973	You have some drag inside the gearbox .......... Friction in the the main shaft bearing (which sits inside a hollow in the input shaft) is the root cause. Will be worst when the gearbox oil is cold and viscous. Nothing to worry about Leadfooted likes this.

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