radiators, heat, and towing

[94ram1500]

I need a few answers on a cooling system upgrade for towing. I'm going to be towing a 3 horse trailer, mainly over curvy roads with steep hills at low elevation, so it will be at slower speeds up to 50mph, the curves and hills are such that I will be going from speed all the way down to a crawl, almost having to break inertia on 7000#, (not quite, maybe a low of 25mph). Ill be using my 94 ram 1500 currently it's stock, 360, auto tranny, 355 gearing, 31"x19" radiator that has the trans cooling lines. It Does NOT have the towing package. Also I'm upgrading to 4:56's in the diffs to take the strain off the trans, and engine. will the radiator from a 2500 with the upgraded core made for towing be a good choice for an easy bolt on upgrade? its the exact same size as my stock radiator, same hose inlet and outlet. also is it better to keep the trans line to the radiator and add an after market tranny cooler, or bypass the stock radiator line set up and run directly through an after market cooler? Thank in advance

 

[ouch1011]

The answer to the question of keeping or bypassing the stock trans cooler in the radiator depends on the ambient temps you'll be using the truck in. The stock cooler also doubles as a heater for the trans to get the oil up to temp quickly on cold days. Colder is not always better when it comes to oil, the trans is actually designed to have the atf at about the same temp as the coolant most of the time. That being said, if you drive the truck primarily in hot ambient temps and/or it isn't a daily driver, just bypass the stock cooler. Make sure you use an aftermarket cooler with a sufficient tube size, otherwise you'll cause pressure issues in the trans. A stock radiator for the towing package will be fine, just make sure the rest of the cooling system is up to the task. My truck never has issues running hot while towing a 5000lb car trailer, including extended up hill pulls at 60mph (about 3/4 throttle in 3rd, mine is only a 5.2) with the A/C on in 90+ degree heat. The coolant maxed out at about 215, which is perfectly acceptable.

You may have already addressed this, but the part that makes me cringe the most reading that you plan to tow so much with a 1500 on steep, curvy roads is the brakes. The stock brakes are not up to that task. Is the trailer 7000lbs or are you figuring the combined GVW will be 7000lbs? If the trailer itself is 7000lbs, I think you need to reconsider your choice of tow vehicle. My truck, with the stock brakes, would struggle to stop that 5000lb car trailer quickly at highway speeds, and it had (surge) trailer brakes. I nearly caused a big accident on the highway once when traffic stopped suddenly and, despite leaving several car lengths in front of me, I barely got the truck stopped in time. Standing in the brake pedal didn't even generate a chirp from the tires... The stock brakes didn't have enough power to even try to lock up the tires with that much weight. I upgraded to larger pistons on the front calipers and rear wheel cylinders (all bolt on stuff) and used the most aggressive "street" pad compound I could find (Hawk severe duty pads) and that helped significantly, but I still wouldn't trust this truck with these brakes towing a 7000lb trailer, let alone on a curvy, hilly road. I've you're figuring 7000lbs total combined weight, you'll be fine as long as the brakes are good. The trans and engine will handle it just fine.

 

[94ram1500]

thanks for the trans info, I never knew or heard about that cold weather function. and I totally forgot to mention about the brake upgrades, I'm going with ebc slotted /drilled disks and yellow stuff pads up front, (its basically the same as the hawk severe duty parts), and rear drum to disc conversion on the rear. Like you, I'm worried about the brakes, I lived in the mountains of new mexico and the stock set up got hot and faded way too much not to mention replacing warped oem rotors every 18 to 24 months. and that was the truck only, no trailer or payload. I cant afford a 2500 at the moment, I'll go with plan B...and stick to the trails on the flatland.

 

[yillbs]

The answer to the question of keeping or bypassing the stock trans cooler in the radiator depends on the ambient temps you'll be using the truck in. The stock cooler also doubles as a heater for the trans to get the oil up to temp quickly on cold days. Colder is not always better when it comes to oil, the trans is actually designed to have the atf at about the same temp as the coolant most of the time. That being said, if you drive the truck primarily in hot ambient temps and/or it isn't a daily driver, just bypass the stock cooler. Make sure you use an aftermarket cooler with a sufficient tube size, otherwise you'll cause pressure issues in the trans. A stock radiator for the towing package will be fine, just make sure the rest of the cooling system is up to the task. My truck never has issues running hot while towing a 5000lb car trailer, including extended up hill pulls at 60mph (about 3/4 throttle in 3rd, mine is only a 5.2) with the A/C on in 90+ degree heat. The coolant maxed out at about 215, which is perfectly acceptable.

You may have already addressed this, but the part that makes me cringe the most reading that you plan to tow so much with a 1500 on steep, curvy roads is the brakes. The stock brakes are not up to that task. Is the trailer 7000lbs or are you figuring the combined GVW will be 7000lbs? If the trailer itself is 7000lbs, I think you need to reconsider your choice of tow vehicle. My truck, with the stock brakes, would struggle to stop that 5000lb car trailer quickly at highway speeds, and it had (surge) trailer brakes. I nearly caused a big accident on the highway once when traffic stopped suddenly and, despite leaving several car lengths in front of me, I barely got the truck stopped in time. Standing in the brake pedal didn't even generate a chirp from the tires... The stock brakes didn't have enough power to even try to lock up the tires with that much weight. I upgraded to larger pistons on the front calipers and rear wheel cylinders (all bolt on stuff) and used the most aggressive "street" pad compound I could find (Hawk severe duty pads) and that helped significantly, but I still wouldn't trust this truck with these brakes towing a 7000lb trailer, let alone on a curvy, hilly road. I've you're figuring 7000lbs total combined weight, you'll be fine as long as the brakes are good. The trans and engine will handle it just fine.

If you have a trailer with trailer brakes and are at 7k pounds, then the issue isn't your truck brakes. Something else is wrong. There is absolutely no reason why would need more than a few car lengths to stop that much weight with proper trailer brakes. emergency braking when towing that much weight is going to be an issue no matter what brake pads / pistons, and truck you have. So that's a moot point.

 

[crazzywolfie]

as long as the trailer has brakes and they are adjusted/working properly then you should not have an issue stopping. something i learned landscaping is if you got electric brakes you almost need to adjust the controller depending on the load in the trailer. most people are not really familiar with brake controllers or adjusting them depending on the load. an adjustment that will work with the horses loaded will likely lock up the tire with them not in the trailer which is where most people leave the controller. you can also manually use the trailer brakes to take some load off the trucks brake with the lever on the controller. you almost need to do a bit of research or play with it if you are not familiar. it really is not too hard

as far as cooling system goes you should be fine as long as it is in good working order and not too much calcium blocking things up. it probably would not hurt to ad a trans cooler on the return line to help provide extra cooling to the trans fluid. as mention the fluid does need to be warmed by the rad but you don't want it getting too hot while towing.

 

[dapepper9]

Clean stock radiator is plenty. 180 tstat and electric fans are great too but not necessarily needed. As for trans cooling, I'm the first to advocate for an external cooler. Placed in front of the AC condenser. I run a temp gauge and being able to watch that has taught me many things.

Also, your plans on gearing. What size tire are you running? 4.56s tow great, sure, but tire size is going to be a large factor. For example, I run 4.56s and basically a 32.5"-33" tire. Considering that towing like that you WILL have OD off (unless you want to replace the trans), if you copied what i have you'd see about 3k rpm at 60. Just a heads up. If you have a stock tire size, you might be happier with a 4.10 gear so you still have a usable rpm without screaming down the highway.

 

[94ram1500]

@ crazywolfie thats a great tip about the trailer brake adjustment to the load, once again I learned something, that's going to save me a lot of grief. My cooling system is in excellent shape, its only two years old as I replaced everything when I had new heads installed...yep they cracked, from a slightly convoluted cavitation related chain of events. (read operator error)

 

[94ram1500]

@dapepper9 I will go up to a 32 inch tire, which is actually a hair under 33 eventually, I need about another year, then I can buy a new used 2500 for my towing and farm work truck, the 1500 will be my 4 wheeler fun rig. I dont have the link to the math formula handy but I can get it for you, with the .69 overdrive final gear reduction, on the highway, the 4:56's will be in the 3:55 range plus or minus a little. I can live with that. right now with my stock 3:55 the final od ratio is 2:80 something,

 

[dapepper9]

Towing you need to go off 1:1 from 3rd, not 0.69:1 from OD. Do not tow in OD

Regular highway cruising, 4.56s are about 2200rpm in OD with a 32.5 tire vs about 1600rpm with 3.55. This is all with converter locked. That difference carries through the highway speeds

 

[94ram1500]

yea I'm not using od when I tow, just highway