Engine/Transmission (1998.5 - 2002) shifting w/o clutch

[rzsolway]

:--) I took my new 2002 Quad cab trubodiesel (3 weeks old, 300 miles) back to the dealer this morning because the steering was slightly off (I had to steer slightly to the left to go straight). The truck was like this when I picked it up, and I was trying to convince myself that it was just the crown of the road. The dealer tried to set the toe, which straightened the wheel, but the tech told me the truck still had a slight pull to the right (I didn't drive it). The service manager told me that the alignment rack at the dealer really wasn't large enough to handle a truck of this size and that they would send it out to a local alignment shop. I'd be interested in any comment son this point. But my real question: while driving the truck, the tech told me that the 6 speed HO transmission was set up "like the big trucks, and that you didn't need to engage the clutch except when starting out or going into reverse, ie. , you could just shift from gear to gear" Anybody ever heard of this!? I'm new to the world of diesel trucks...

Thanks, guys... .

 

[RustyJC]

Originally posted by rzsolway

:--) But my real question: while driving the truck, the tech told me that the 6 speed HO transmission was set up "like the big trucks, and that you didn't need to engage the clutch except when starting out or going into reverse, ie. , you could just shift from gear to gear" Anybody ever heard of this!? I'm new to the world of diesel trucks...

Find another tech as fast as you can. The NV5600 is a synchronized gearbox. Big rigs use non-synchronized gearboxes. Ours have to be shifted using the clutch (if you want to keep the teeth on your synchronizers) - the big rigs don't.



Rusty

 

[rzsolway]

That makes sense to me. The guy seemed like a real jackass.

 

[BV]

Clutchless shifts

Pretty sure it's still less expensive to turn a flywheel, (edit) REplace pressure plate & disc and put in a new throwout bearing then it is to replace the syncho's inside the transmission.



My vote is with Rusty - Find a different shop or DIY.

 

[Chipstien]

:-laf :-laf :-laf :-laf :-laf :-laf :-laf :-laf :-laf

 

[66gt350]

shifting w/o the clutch

Don't most big rigs have NO synchro's in them?... That's why they have to double clutch to shift gears. Because there are no syncro's in the transmission, they have to release the clutch and manually synchronize the speed of the engine and transmission before either up or down shifting. If you know what you are doing and know where the rpm shift points are, shifting without the clutch won't hurt the synchro's or the transmission.

 

[rickhans]

TDR had an article last year by Standard Trans. in Ft. Worth that talked about this. When I was over at their shop they showed me what the synchronizers and gears look like in a transmission where the clutch was not used. It really chewed them up.

 

[M Barnett]

Don't most big rigs have NO synchro's in them?... That's why they have to double clutch to shift gears. Because there are no syncro's in the transmission, they have to release the clutch and manually synchronize the speed of the engine and transmission before either up or down shifting. If you know what you are doing and know where the rpm shift points are, shifting without the clutch won't hurt the synchro's or the transmission.

Yes, in a way thats what double clutching is. Double clutching only makes the shift faster without the synchros. Use the clutch in your Dodge.

Michael

 

[66gt350]

How is double clutching faster? It is alot more involved that using the clutch normally.



If you know where the shift points are, shifting without the clutch won't hurt the synchro's. It's when you don't know and grind the gears or you are power shifting that will destroy the synchro's. All that needs to be done is to equalize the motor speed with the current transmission shaft speed close enought to be able to shift without harming the synchro's or the gears. The last truck I had for over 15 years. I shift constantly (both up and down) without the clutch, and never had any adverse effects with the operation of the transmission or any metal shavings in the fluid.

 

[RustyJC]

When shifting using the clutch, the synchronizers have to match the following to the speed of the output shaft:



1. Input shaft



2. Synchronizer hubs



3. Clutch disc



When shifting without using the clutch, the synchronizers have to match the following to the speed of the output shaft:



1. Input shaft



2. Synchronizer hubs



3. Clutch disc



4. Pressure plate



5. Flywheel



6. Crankshaft



7. 1/2 of total piston/connecting rod mass (generally considered as rotating mass when balancing an engine)



8. Mass of all accessories driven by engine



At the end of the day, it's your truck, your transmission, your money and your choice. Do what you think is right.....



Rusty

 

[66gt350]

What does the mass of the accessories and the rotating mass of the engine have to do with shifting gears? You've lost me on that one. The crankshaft, flywheel, pressure plate... etc,etc. are all spinning at the same rate (well, at least you hope they are). And the clutch disc is spinning the same as the input shaft of the transmission...



All that you are doing when shifting without the clutch or double-clutching is matching the engine rpm's to the rpm's of the gear that you want to shift to. It's not rocket science, but you have to learn where the shift points are.

 

[Bigramguy]

Rusty is right. Even though you are matching the engine RPM to the trans RPM,there still will be a slight difference,which will put extra stress on the synchros.



To put it simply,when using the clutch,the synchro only has to match the speed of the gear to the shaft which it rides upon,which is usually the mainshaft,thereby locking it to the shaft and transfering power through it. When not using the clutch the synchro is trying to match the speed of the entire drivetrain,to the entire reciprocating mass of the engine.



If done correctly,not using the clutch,won't hurt it much,but over time it will shorten the life of the snychros.

 

[rickhans]

If you don't mind an exagerated (and a little silly) comparison, look at it this way: compare the effect of using a screw gun to drive a screw into a board versus using a sledge hammer. All of that mass they are talking about equates to weight that has to be slowed down if you miss a gear (or your timing is off).