Is it better to push the clutch in when starting the truck?

Apparently manufacturers don't see it as a major issue since they have installed opti-idle systems in manual trucks for decades. Of the trucks I have owned, I have only had to replace 1 started and it was on a truck with over 700k on the clock...so it must not wear them out that much faster...and of the company trucks I have had that were equipped with opti-idle, I had never had one that needed a new starter, and on average that system started the engine dozens of times every time I was on my daily rest break. And today's automated transmission trucks don't hit the clutch pneumatics when you turn the key to start it.

 

Oh the that’s right your the smartest person ever when it comes to Physics, and inertia and resistance
You a company driver not a O/O so the trucks you owned on American Trucker simulator don’t count

 

Its the lubrication factor I was pointing out. There's only just residual oil film between the crank and thrust bearing when the engine starts cranking. If the oil is frozen its going to take at least a few seconds before oil pressure begins to lubricate that thrust bearing. Is that worse in the long run? Maybe, if the engine has the wrong oil in it for the winter season.

 

Back in the 60’s and 70’s the chances of you finding an automatic transmission in a truck especially a class 8 truck was virtually unheard of.
The first one I saw was a GMC ten wheel dump truck, it was a hydrostatic transmission.

 

The CDL started in 1992
As others have posted there were Auto trans in Big trucks before that I saw a couple in the mid 80’s
Reread his post I quoted it just proves he knows not what he is talking about he is just talking out his back side like normal

 

Allison started developing and selling automatic transmissions for large trucks in the late 50's and continue to do so today.
Allison Transmission - Wikipedia

JD

 

Your theory is correct but when everything is considered it’s still less stress, wear to disengage the clutch. By the way you will have luberication before the gauge can react. Don’t fool yourself thinking the gauge reacts as fast as the pump in this situation and that residual oil on avthrust serface has already been taken into consideration with the design of the system.

 

I haven’t replaced a starter yet! Need I say more.

 

I was chatting with a technical trainer for a large construction manufacturer recently. A few years go he was involved in some lubrication system testing and they found it took 15W-40 about 6 minutes to reach the valve train in a large diesel engine in winter temperatures. IIRC 10W-30 was a couple of minutes and 0W-40 was several seconds. Of course the bottom end being closer to the pump will get oil faster obviously but I'd imagine the thrust bearing wouldn't be seeing lubrication for several seconds of cold cranking with 15W-40. Residual oil film in modern oils would probably handle it though.

I'm not saying either way is the correct way either. On the heavy equipment side of things a lot of that stuff doesn't have a clutch (excavators, hydrostat drive dozers, wiggle wagons, loaders etc) and they start just fine in winter despite the drag of the pumps and transmissions.

 

I appreciate having a discussion as opposed taking the stance of I am correct no argument accepted. My answer is based on bearing replacement, thrust cuts to fix worn thrust surfaces on engines ranging from small one cylinder to things some would have a hard time picturing and the frequency of those issues compared to gear/teeth and starter replacement.
I would however argue that load transfer based on resistance in the main shaft would negate any benefit you might possibly create.