No more manual transmissions in a Duramax - why?

[Bravo Whiskey 21]

The duramax has soo much torque it was wrecking the manuals.
I do not drive for a living but towing my boat thru the PA mts. and my dump trailer using the '06 allison in manual mode is fantastic. I almost never have to touch the brakes. When I fish the NJ shore I end up coming up thru the Blue Rt or "SureKill " expresss way towing my Whaler.Tough roads as most of the way is only 2 lanes. Just push the tow haul mode button and I 'am not getting cut in front and can deal w/ the short stops/fast start ups that come w/ an outdated highway.
I drive stick, learned @ 11 yrs in F350 SA wrecker ,driven many since, but I feel the Allison is overall a better choice then a stick.

[Hook_'em_Horns!]

The duramax has soo much torque it was wrecking the manuals.
I do not drive for a living but towing my boat thru the PA mts. and my dump trailer using the '06 allison in manual mode is fantastic. I almost never have to touch the brakes. When I fish the NJ shore I end up coming up thru the Blue Rt or "SureKill " expresss way towing my Whaler.Tough roads as most of the way is only 2 lanes. Just push the tow haul mode button and I 'am not getting cut in front and can deal w/ the short stops/fast start ups that come w/ an outdated highway.
I drive stick, learned @ 11 yrs in F350 SA wrecker ,driven many since, but I feel the Allison is overall a better choice then a stick.

I’ll have to agree. Many years ago, I gave up on ‘disposable’ automatic transmissions and drove hand-shakers for 16 years. The Allison has changed my mind, all of the benefits of control from the manual and no sore knee from driving in heavy traffic. The best part is…no more clutch jobs every 80k miles.

Incidentally, the most recent demographics show less than 15% of the population can even drive a stick much less own one. I believe the popularity of the manual in the Fjords and Goats has been due to the crappy Auto that was available in the past. Now that Fjord has the Torque-Shift and the Goat has the Aisin, things will probably change on those too.

[93_Burrito]

GM insists on using a dual-mass flywheel in front of the manual tranny to keep the chatter down. Doing so creates the reliability issue. GM can't make a durable flywheel in this manner. The aftermarket provides excellent solutions to this problem, though. Want a solid flywheel? Okay. Want a double-disc clutch setup? You can have that, too, behind a Duramax.

A ZF-6 truck with 300 HP is still going to put down numbers very similar to a 360 HP Allison truck at the rear wheels. The automatic has greater parasitic loss.

Of course GM is going to sell fewer manuals if the people assume they aren't out there to be had. And people will only search for so long before they get fed up and settle for something they didn't really want. Or they shed their brand loyalty and move on to another company who will give these people what they really want. Like manual transmissions and solid front axles...

[gophergunner]

if they made the transmissions with many gears and close gear ratios so i could shift like a big rig then i wouldn't mind driving a manual pickup in the city........but since they don't make them like that, i have to admit that the auto sure makes life easier on my left leg.

[93GMCSierra]

from what I have seen most of the diesels are easily shifted by engine RPM no clutch needed. However I have never driven a duramax so its possible that it will not work that way.

[xtrempickup]

i have to admit, i was searching for a manual truck with the 6.5L when i was looking, and i settled for the auto. sold that, looked for a manual with a 5.0L or 5.7, settled for the auto again. hard to find the 5 speed trucks. but its not so bad being able to just push a pedal to stop and go. i guess my other 5 vehicles that are 5 spd will have to do

[Hubert]

I agree mainly 3 reasons.
1. Emissions
2. Clutch (GM just fails miserably at this from clutch pedal assembly squeak to flywheel and disc hub etc).
3. Perception and Market.

3. GM has literally STUNK at clutches since well I am not sure they ever made a nice clutch. So most GM loyalists have given up and converted to Auto's

In comparison Ford and Dodge seem better easier clutch pedal pressure and smooth quiet motion. Yeah they all tear up if you up HP and push the limits but Manuals with good clutches can be mated to high HP. Auto will still take a bit more if also built in the light trucks but again GM could do so much better....

I am hoping they will eventually try again but in 10 more yrs a manual will be a collectable.

[93GMCSierra]

I have to agree on the clutch pedal pressure, I have the 93 nv4500 and my brother has a dodge with the nv4500 and his clutch is so easy to press.

[MaxACL]

My six speed has 300,000 on it and never been worked on. The dual mass flywheel is another story. I went through many till I found a single piece at South Bend Clutch.

I just replaced my transfer case (again) and Mr Good Wrench pulled the 6 speed to look for other trouble, and with 30,000 on this new single piece flywheel the surfaces looked new. the machine grooved was still there. Gotta love it!

Mike

PS I do get leg cramps in city trafic.

[More Power]

The 6-speed manual GM used in the 2500HD/3500 diesel pickups was identified as a "ZF S6-650". The "S6" identifies this as a 6-speed. The "650" identifies the input torque limit.

As has been mentioned here, the originally introduced flywheel was a problem. An updated flywheel was released in July 2004 that was designed to increase life, improve friction control and reduce transmission input shaft wear.

Here's a clip from an article I wrote in 2004:

The ZF S6-650 six-speed manual transmission first became available in GM's 8.1L & Duramax equipped 2500HD/3500 series pickup trucks beginning in the 2001 model-year. Lower cost, improved fuel economy and a performance advantage in certain situations are among the more important reasons owners express when selecting the ZF six-speed. The S6-650 is also available on C4500 & 5500 medium duty trucks.

ZF S6-650 Key Features:

• Designed specifically for high torque pickup trucks.
• Synchronized in all gears.
• Dual-cone synchronizer in 2nd and 3rd gears.
• High helix angle gearsets provide high contact ratio and quiet operation.
• Lower shift forces w/ tight shift pattern.
• Lightweight integrated aluminum housing
  (front, center & rear).
• Center bearing support for improved durability.
• Reverse & 1st gear location improve maneuvering ease.
• Overdrive 6th gear shift lever position located forward and away for improved passenger comfort.
• Gross Combined Vehicle Weight Rating up to 26,000-lbs.
• Left & right ISO/SAE 6-bolt Power Take-Off ports.

Jim