Engine/Transmission (1994 - 1998) Joe D.-Tell me IT AIN"T SO!!!

[BigPapa]

Reading Joe Donnelly's article on clutches in the new issue, I read that reverse is hard on the clutch because it's turning backwards?



Joe, PLEASE tell me you were on some serious pain medication or something when you wrote that! The clutch turns with the flywheel and the flywheel is bolted to the crank. There is no way the engine runs BACKWARD in reverse! :-laf



Surely this didn't come from the man who built "Old Sickly".



Scott

 

[RT66DOC]

Pressure plate, maybe?

 

[FATCAT]

Clutch running backwards??? Pressure plate running backwards???



You guys need to see this site: http://auto.howstuffworks.com/transmission5.htm

to see the Idler gear which is used to put a manual transmission in reverse. A small gear that comes between the layshaft reverse gear and the main shaft reverse gear.



I think Joe D. "misspoke" in the article.

 

[RT66DOC]

Clutch running backwards??? Pressure plate running backwards???



You guys need to see this site: http://auto.howstuffworks.com/transmission5.htm

to see the Idler gear which is used to put a manual transmission in reverse. A small gear that comes between the layshaft reverse gear and the main shaft reverse gear.



I think Joe D. "misspoke" in the article.

Yes... I was thinking through this again last night. What I meant was the clutch disk but that's wrong, too. I think (maybe) what Joe was referring to was that when the pressure plate clamps on the disc the rotational friction forces on the disc in reverse would be opposite those forces when in fwd. I recall a similar comment from Peter at SBC.



Could be wrong about this, also. Anybody?

 

[HBrunton]

the input shaft will always spin the same direction, when the reverse idler gear is engaged the output shaft will spin the opposite direction. All manual transmissions have some sort of arrangement with a reverse idler gear. Really confused on this one, but I have not read the article yet. Still waiting for magazine to arrive.

 

[george]

Back to the main point

Confused is right, but back to the main point, is reverse really hard on clutches?

 

[Yo Hoot]

The only reason I can think of that might make reverse hard on clutches is the fact that you are usually slipping it under load to park a heavy trailer.



Other than that there is no difference in forces. As others have said the changes take place inside the trans, not in front of it.

 

[Lnwing]

It seems to me that the only time there is any "reversed " force applied to the clutch is during deceleration when downshifting or using an engine/exhaust brake to slow the vehicle.

 

[Bob V]

It seems to me that the only time there is any "reversed " force applied to the clutch is during deceleration when downshifting or using an engine/exhaust brake to slow the vehicle.

BINGO, we have a winner!

 

[BigPapa]

Everyone has a constitional right to be a moron.

I couldn't have said it better myself. :-laf



Scott

 

[Vaughn MacKenzie]

I'm thinking since many guys have a little trouble shifting into reverse and it grinds or jerks a bit that may cause the input shaft & pressure plate to jerk in the opposite direction for a split second.



Vaughn

 

[SRadke]

Even with the grinding, jerking, or whatever abuse you put it through in reverse the clutch sees the same forces as if you were doing it in a forward gear. To say it's jerky because it's turning backwards thus the springs in the hub can't help you is just incorrect. I'm afraid Joe slipped on this one and it's unfortunate the editors didn't catch it. Such is life with publications and why those couple pages are at the back of the magazine to right the previous months errors.



-Scott

 

[NIsaacs]

I agree that the clutch sees the same torque direction in forward or reverse gear. However I can't quite figure out why, if the torque direction is the same, why does the torque of the motor change direction while in reverse. In other words, in forward gear the torque on the engine block is against the left hand motor mount but in reverse the torque is on the right hand one. Yet the motor is still producing it's torque in the same direction. Some one help me out here.





"NICK"

 

[Extreme1]

In other words, in forward gear the torque on the engine block is against the left hand motor mount but in reverse the torque is on the right hand one. Yet the motor is still producing it's torque in the same direction. Some one help me out here.

"NICK"

What makes the engine push against one side or the other is torque reaction. Take the engine and clutch out of the picture for a minute. Think of trying to twist a shaft real hard. Now twist it the other way. The engine and trans are just getting the torque to the trans output shaft and the rearend is resisting.



The only thing controling which way the force is being applied is the idler gear in the trans.

 

[NIsaacs]

Extreme 1, thanks, that helps some, but my brain is still somewhat foggy. If you take a remote mount aux. transmission and use underdrive the torque is on the left mount, direct has no torque on the case and in overdrive the torque is on the right mount. No reverse idler. I need more help here, thanks.





"NICK"

 

[McCRam]

The movement you see at the motor is a result of the twisting force on the driveshaft, after the transmission. In reverse the driveshaft is turned in the opposite direction than the forward gears.

 

[6btsmoker]

i believe that reverse has a syncro, in the dodge spec nv4500. should not grind into reverse unless there is a clutch or syncro problem.

 

[HEMI®Dart]

I read through Joe's Clutch article in the new TDR and can't find where he said that.

 

[K5IP]

I think this was just a test.

Joe wanted to know if anyone out there was listening.

Actually, I think some folks actually passed the test.

Rog

 

[BigPapa]

Page 10, right above the picture. The last sentence in the paragraph,

"Note that backing up is the worst case situation because... ".