2010 auto transmission question

[ahpn]

Hey:



Have a, 2010 3500, srw, lwb. Towed my first heavy load today. 12k Tractor and trailer combined, through back hilly roads of New Hampshire. Probably about 80 Miles. Last two miles was on a dirt road up some pretty steep grades. Put it in four wheel drive and at points was barely able to get up and over hills with all four wheels spinning at times. As I am approaching my fields up a gradual grade it seemed like the transmission was either slipping or would not come out of first gear. Engine was revving and not making much time. Once I stopped I shut it down and could smell what I assumed was burned transmission fluid. Temp gauge showed 270. I let it sit for an hour and just took it for a spin and it seemed fine. Kind of bummed bought this truck thinking that it could do what I did today without a problem. Just wondering what was going on, is this normal? Should I be worried that I fried something? Was I expecting to much out of the truck or are they capable of this type of use? Just wondering and would appreciate any imput.

 

[DThweatt]

270 is way high on the temp. I'd probably flush the fluid out when you get a chance so the seals in the transmission don't harden.



if your pulling a load that heavy on a steep climb, in loose dirt I would have used 4 low and pulled slow. it should help keep the transmission temp down a little by using the low gearing more.

 

[AH64ID]

I would recommend using 4 low in those situations... I also don't think your supposed to shut the truck off with the trans that hot. . let it idle in P or N to cool the trans.

 

[Matt400]

*12k Tractor and trailer combined, through back hilly roads *Probably about 80 Miles. *at points was barely able to get up and over hills with all four wheels spinning at times.

I don't own a new 6 speed auto but wow. . sounds like you needed to use 4 low and get into a gear that would allow the converter to lock up. Idling in neutral would have been better than shutting it down as the fluid had no way to circulate through the cooler. Maybe someone can chime in on what gear will lock up the TC on the new 6 speed?



I would change out all the fluid and cross my fingers.

 

[tp0d]

Was I expecting to much out of the truck or are they capable of this type of use?

Yes they are capable of this type of use, but its just a piece of machinery. No brains. Which means something with a brain has to properly operate it. (no offense, just illustrating my point)



I think you might need to do some reading on towing heavy. .



-j

 

[Hoefler]

I experienced the same thing towing my 40' fifth wheel through the Big Horn pass on gravel, 22 miles of very rough un improved road. What is happening, when you are going that slow the torque converter never locks up, creating tremendous amounts of heat. I actually saw my gauge pegged and the over heat alarm for the transmission came on long after. The comment above about using 4-lo is spot on. I wound up stopping and going to 4-lo. When I did, the transmission shifted all the way to 5th gear and locked up the converter doing about 8 mph. With in 1 mile, the alarm went off, the temp was dropping like a rock and settled in at 190* where it runs normally.

 

[Weatherman1964]

I plow snow in Michigan. I push heavy piles around parking lots. When my temp gauge gets to around 200, I put it in 4-low and the temps will come back to about 150. I've been doing that for years and I haven't had any burnt transmissions.

The auto 6-speed will lock up in 4th that I know of, it's a 1:1 gear ratio. I believe 3rd may lock too, but don't quote me on it.

 

[HBarlow]

Earlier years with 48RE four speed automatics would lock in 2nd, 3rd, and 4th. I don't know anything about the new MOPAR six speed automatics but if I had to guess, would guess they are capable of locking in 2nd and above also.

I believe my Aisin six speed automatic locks in 2nd through 6th gears.

A savvy driver with his ear tuned and eye on the tach can sometimes manipulate the ECM/PCM with his throttle foot by backing off momentarily and causing the automatic to shift up and lock the TC.

 

[Yo Hoot]

Funny the engineers said we don't need gauges, the truck has safety features "built in" LOL

But to respond... . LOCK UP SWITCH is the cure. Not sure if it's possible on the new ones but it is on the older ones (pre-68RFE).

 

[ahpn]

Yes they are capable of this type of use, but its just a piece of machinery. No brains. Which means something with a brain has to properly operate it. (no offense, just illustrating my point)



I think you might need to do some reading on towing heavy. .



-j

I am an idiot... . and you are right I do need to do some reading. Going over the replys to my post made me realize how much I "don't" know about towing heavy.



Appreciate all the insight... good stuff.



Norton

 

[ahpn]

Another question. What is happening when the torque converter is locking up? What does that do, ie: why do you want that to happen? Do you lock it up in a specific gear as you begin your climb or does it pcik the gear to lock up in?

 

[HBarlow]

The torque converter is a hydraulic clutch assembly between the engine's crankshaft and the automatic transmission's input shaft. It operates automatically by design with input from the ECM (engine control module) and/or the PCM which (I think) is the power control module. It consists of two major components basically a rotor and stator or drive wheel and driven wheel with clutch plates between.

At low engine speed the torque converter is allowed by design to slip breaking the connection between engine and transmission. That is what allows the truck to sit still at idle and gently and smoothly launch the truck when you press the accelerator pedal. When the torque converter is open, unlocked, the rotor and stator with fins or blades are spinning in oil generating heat.

The ECM or PCM and the automatic are designed to "lock" forming a direct connection between engine output and transmission input at a certain rpm in a specific gear.

 

[sag2]

The torque converter is a hydraulic clutch assembly between the engine's crankshaft and the automatic transmission's input shaft. It operates automatically by design with input from the ECM (engine control module) and/or the PCM which (I think) is the power control module. It consists of two major components basically a rotor and stator or drive wheel and driven wheel with clutch plates between.



At low engine speed the torque converter is allowed by design to slip breaking the connection between engine and transmission. That is what allows the truck to sit still at idle and gently and smoothly launch the truck when you press the accelerator pedal. When the torque converter is open, unlocked, the rotor and stator with fins or blades are spinning in oil generating heat.



The ECM or PCM and the automatic are designed to "lock" forming a direct connection between engine output and transmission input at a certain rpm in a specific gear.

Well, pretty close.

Think of the converter as two fan blades facing each other. One is attached to the engine, one to the transmission input shaft. As the engine fan spins the air hitting the blades on the transmission makes the other fan blade spin. In a real transmission there is a stator with a one way clutch placed between them, and they are in oil instead of air. The shearing of the oil as it passes past the blades of the fans and stator blades is what generates the heat. The stator is what makes the torque multiplication. It redirects the oil to push harder on the transmission side blades.

In our converters there is a clutch plate at the front face (engine side) of the converter. It is splined to the input shaft and spins free until we want to lock it up. At that time there is a piston that pushes the clutch plate against the front of the converter, locking the converter housing to the input shaft. No slip=no heat.

 

[RPlamondon]

07. 5 6. 7, auto, 2500, hd, SLT, quad cab 4x4, 3. 73 and tow 10-11k cross country and back, low mileage but no major problems so far. Use trans shift lever up/down gear changer as much as possible to downshift before hills. Try to let engine do the work by having trans in proper gear at all times. Had all fluids changed at 33k, both differentials, both transfer cases, transmission. Cost mucho money but I believe worth it in long run. Plan to keep truck a long, long time.