6.7L I6 / 68RFE Transmission Temp Towing

[2013megacab]

I found the temperatures to be much better behaved when I kept the RPMs at around 1750. IIRC that is the torque peak for the engine. I selected the gear and speed to keep the engine around 1750 when we did the lower third of the Blue Ridge Parkway last month. If I broke concentration and let the RPMS get too high, it ran hotter.

Al

 

[twscfltx]

The bottom line is:
• If the TCC is locked, your temps should be OK.
• If your TCC is not locked (or won't stay locked), then drop it down (manually) to a lower gear (so hopefully, the TCC can lock and remain locked).
• If your TCC won't stay locked up in 2nd gear, then drop it all the way down to 1st gear. The TCC will not lock in 1st gear, but running in 1st gear unlocked gives you MUCH less heat than running in 2nd gear unlocked.

Please give advice to compare aftermarket options:
Deep pan vs Cooler

 

[RUSSELL5000]

My trailer is relatively light in comparison to the capability of the truck. I had the transmission temperature (and coolant temperature) rise on my first real trip with the trailer - I have a similar thread asking a similar question. The situation was such that was alternating back and forth between first and second gear (caught behind a construction truck on a steep hill).

I have applied the advice given here in going to first gear in such a situation and have never had a recurrence of increasing transmission temperature.

I added the PML deep pan to be on the safe side and I have never seen a transmission temperature over 170 since then. I would think a deep pan and driving as recommended would do the trick.

 

[jelag]

So I was looking under the hood today..... It looks like the tubing to the transmission is 5/8" or so... I'm sure its a metric number..... here's my thought... I've never seen an off the shelf transmission cooler with 5/8" tubing.... I'm guessing the best move would be to get the extended pan....

BTW.... what's the capacity of the pan..... when you pull the transmission oil pan down.... how much oil can I expect to splash in my face/on the ground....

 

[transe]

The trans cooler lines are actually 1/2" nominal tubing size.
For a normal "pan drop" the drained fluid is typically about 7-1/2 quarts, but it varies depending on how long you let it drain for. You can get up to an additional 4 quarts out of the converter, as it will SLOWLY drain out over time.
I'm not sure which option (deep pan or an added cooler) would be more beneficial. Worst condition for trans cooling is typically a long slow grade climb with trailer, with the converter unlocked. In that condition, you generate a lot of heat, but don't have much airflow to cool it. So an added cooler (especially one with an electric fan) would remove more heat, but then a deep pan would spread the heat through a greater quantity of fluid (which would slow down the overall temp rise). Bottom line, though, you probably don't need either if you follow the recommendations (manually downshift the trans to the lowest possible gear when towing up a steep grade, if the TCC is unlocking when in a higher gear).

 

[jelag]

TransEngineer.... my 2013 is new to me... and it has never towed.... I've been told on this forum to try it without either, a deep pan or the cooler... so I'm going to do that... but the filters are here and I have 2 gallons of fresh fluid so that's on my list.... However all the coolers I've looked at... if I need one are either 5/16" or 3/8" tubing and I just assume they wouldn't flow enough fluid to really do the job.... but I've not yet looked at the lines to the existing cooler... that's this weekend.

 

[RUSSELL5000]

Jim,

I picked up an old "kiddie pool" at a garage sale for $10 when I dropped the OEM transmission pan. I suppose one could do a better job than I did of being neat and catching the fluid, but it did make a mess! All went in the kiddie pool which I then drained. I guess the $10 was spent to not have to deal with cleaning up. It was much better than splashing all over the garage floor.

The replacement pan has a drain plug.

 

[jelag]

well.... I hate to admit this but I own a vacuum pump with the tooling to drop it down the dip stick tube and draw it up... the problem is.... its at my other home 1500 miles away... and I'm not interested in buying a second one... but I like your $10 pool idea... of course it would cost 25 cents per truck... but it would be nice to have a drain plug..... if I had the time I'd bore the pan and weld in the gear to make that work.... but not this time... at least I know that I have about 8 quarts to deal with... thanks for all your thoughts..