Auto transmission question/observation...

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I typically leave my transmission in N when idling prior to shut down and as a result, often shut the engine off with the transmission in N. I have noticed that at the next start up, the shifting from P to R or D is much smoother...

Any reason for this? Anyone else noticed?

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'01 2500 SLT+, QC, LWB, 4X4, 3. 54s, AT, SPA guages, Alpha Liner, every option but running lights!

'98 DUCATI ST2 "Bombed" 944CC with Ducati Performance Carbon Fiber Exhaust, F. I. M. Chip, K&N and "modified" air box.

 

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I can tell you what the difference is... . but I can only guess why it is smoother. Here goes, when the transmission is in Neutral the hydralic pump in the transmission is working. We have been told on this site that the neutral position is a better position for a cold truck to warm up because the pump is circulating fluid. With the truck in the Park position, the transmission pump is idle. My guess is..... if you have a little bleed off when the truck is shut down then when you put the selector into Reverse or Drive you would have a bit of lag time before the pump can "catch up" and all pressure is up. That would give you alittle rougher shift.

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98 Properly Valved 4x4 SWB QC ISB A/T Metallic Red w/ tan cloth interior, DC nerf bars, DC two piece mud-flaps, 275 h. p. injectors, Monroe Gas Magnums, Armor Tuff spray in bed liner, Goodyear Wrangler ATS 285/75r/16, BD Heavy Duty Valve body. Walker 21468 thru flow muffler,
Cobra 29 NWST CB.

 

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Scooby,
Transmission is pumping oil all the time, doesent matter the gear you are in. By letting the truck cool down in neutral it is like having a standard transmission with the clutch in.
Chances are while you are letting this thing cool down in neutral you have the parking brake on( just a guess on my part). If that is the case, when you actually engage park the load of the vehicle is actually being placed on the parking brakes rather than the park pawl on the transmission(parking rod).

Parking rod inside the transmission is similar as if you had 2 gears and you stuck you finger in the middle of them to prevent them from turning.

So try removing your finger from in between those gears, it would take considerable force to pull that out. A little exagerated example ,im sure the park rod wont feel any pain. The difficulty you feel sometimes in moving the shifter in the morning is the parking rod trying to be pulled out from the weight of the vehicle.

When you shut if off in neutral with the e-brakes on, the load of the vehicle is actually on the e brakes not on the parking rod. This will help it be easier to select gears in the morning.
P. S.
I think the method you are using for shut down is definately the best way,especially for people with sloped driveways.

Hope this helps,
Bill

 

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Thanks again Bill!

The only comment is that previously, when I would let the truck cool down (idle) in the park position, I would still always apply the e-brake prior to releasing my foot from the service brakes - thinking that I was letting the weight of the truck rest on the ebrake and not the transmission...

Oh well, good to know that I'm doing a better job now! Always learning... . that's what seperates us from the animals!

 

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Bill,
When I had my ATF changed, I had it completely changed out to synthetic. I went to a place that used a "power flush" machine that was connected into a trans cooler line. When it was time to start the process of removing the old ATF and replacing it with new ATF, we needed to put the transmission into a position other than Park to get the ATF moving through the system to perform the swap.
What parts of the transmission are active/pressurized in Park?

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'95 2500 SLT ClubCab, automatic, 3. 54 LSD

 

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I am not a big believer in those power flush machines. I guess i am from the old school. I believe in dropping the pan,& servicing the filter.
The tc part of the system within the transmission is like a balloon. It is impossible to get all the debris and garbage out. Since the dodge ram cannot be reversed flushed because of the one way flow valve within the system , it really doesnt make a lot of sense to power flush.
To answer your question, nothing in park is pressurized, the oil is merely dumped back into the sump.
One more footnote, when you are power flushing a system, it is very easy to lodge a piece of fibre or metal within the intermediate shaft of the transmission.
Bill