Advice on tire size, towing, and the 68rfe transmission

[davalt75]

Hey, guys.. I'm new to the forum and new to Ram trucks. I have owned two diesels previously, both Fords. But I just put a deposit on a 2021 2500 Laramie with the 6.7 Cummins, 68rfe transmission, and 3.73 gears. From reading on the internet I've learned the 68rfe seems to do well if you are bone stock and use it as a daily driver but problems abound when making modifications such as bigger tires, tuning, and then either or both of those combined with towing. So I was hoping for a little advice from some of you who have put bigger tires on your trucks and still tow. 90% of the time my truck will be used as a daily driver, mainly around town. The heaviest thing I tow is a 35 ft. travel trailer that is 8000 lbs. empty. So not super heavy,and that is usually only 3 to 4 times a year. So my question is, would the change in tire size be asking for trouble considering the weight I will be pulling and also considering no more often than I'll be pulling it?

 

[mlrtimemach]

Lot to be considered. Larger tires change how the gears pull. Will you be pulling flat ground, hills or mountains?
I have a 2500 4x4 with 6.4 an 3.73's an I talked myself out of the leveling kit. Decided I wanted the full value of towing out of the truck to pull our 7,000lb Jayco while having the bed loaded with stuff. Glad I did. Truck performs well fuel mileage is good not having larger tires.
To each their own on bigger tires an towing a camper. It's harder on the truck and again it depends on the ground your dragging your camper on as to how much more strain it is on the truck

Sent from my SM-G950U using Tapatalk

 

[davalt75]

Thanks for the advice. I'm in SC so it's pretty flat around here. Hardly any hills to speak of where I usually pull. I had a 2" leveling kit and 35's on my 2018 F250 with the 6.7 Powerstroke and 3.55 gears. It pulled my 8k # travel trailer like a champ. I have no doubts my new Ram will pull it just fine as well. I have just read so many horror stories about the 68rfe that I'm a little worried now. In my mind a jump to 35's isn't huge, but I don't really know how much that extra.2 nches of height will affect the torque load on the tyranny.

 

[KKBB]

Put your mind to rest. You will be fine. Hardly any 68rfe issues. The ones that had some problems were mostly several years ago...they have made improvements. Even back then, most of the issues were big tires and a boat load of extra power added and towing all combined. I had several cummins with the 68...all had more power...most had bigger tires. I towed way more than your 8k trailer and never once an issue

 

[davalt75]

That's what I was hoping to hear. I didn't feel like the relatively small difference in tire size would make that much of a difference but it makes me feel better to hear it from someone who has had real world experience with this transmission. The last thing I want to do is buy a $70K truck and kill the transmission straight out of the gate. You can find all kinds of opinions on it if you start digging around in threads like this. But like I said 90%-95% of the time I will be driving unloaded around town anyway. It might be different if I was hauling everyday.

 

[KKBB]

There can always be that rare lemon, but overall it is a very stout transmission for a stock truck, even for a truck with a little more than stock power!!!

 

[TWILLIAMS9]

You’ll be fine. Doubt you would notice much of a difference with just 35’s.

 

[davalt75]

That's what I was thinking.and hoping someone would confirm. Like I said, I only tow with it 3-4 times a year and that is on flat ground mostly on the highway.

 

[Nickx86]

If you keep the 68rfe near stock (no crazy tuning) and your mods pretty reasonable like 34” tires and a leveling kit. Your 68rfe will serve you well for years and it will shift smoother than a typical aisin...plus your service intervals will be longer compared to an aisin

 

[RaptorHD]

I am also in South Carolina!

I had a 2008 3500 dually, now have a 2500HD both 6.7 Cummins trucks.. I used to pull all the time, now I am retired so I just pull the car hauler for my hobby..

The 68RFE is a great tranny as long as you follow maint. intervals. There are a few things you can do also to ensure long life, I put a deep sump pan on the 68RFE, it has internal baffles and external fins.
https://www.ebay.com/itm/293241948209?epid=253628776&hash=item4446950831:g:9LgAAOSwHGZdhmYe
Now, the pan I got had internal baffles so it won't work.. I actuall went to my machine shop and had them milled down.

You will also want one of these: https://www.ebay.com/itm/254323483165?epid=23033747399&hash=item3b36dc621d:g:gFEAAOSwEyhdSs1u


Tires:
I ALWAYS run commercial tires and wheels! I had them on my dually (19.5 wheels) and had half the tread left when I sold it @115,ooo miles on them!
I am making a set of custom wheels for my 2500HD, then I am putting a set of 265/70-19.5 on them. the 19.5 tires are maybe 2" wider than the original wheels and 2" taller.. Best of all they (unlike large ass tires) allow you to run your max payload, run at higher pressures which reduces ground friction/contact and thus lower heat. 20/32 tread depth, load range H... Believe it or not,,they usually are cheaper too!

when it comes to my trucks, I am a function over form/looks person, My muscle-cars are the whole looks thing..

 

[RaptorHD]

here is the actual pan I have: https://www.ebay.com/itm/164824346934?epid=1843836143&hash=item26604bf136:g:3r0AAOSwYEJgf0U~