Secondary Trans Cooler Question

[colestat]

We have a 2014 Forest River Sunseeker 3170DS Class C RV. We just got set up with a Readybrute system to tow our 2013 Jeep Wrangler Unlimited. We took our first trip with the toad 2 weeks ago from NJ to Vermont and the RV seemed to strain on the slightest uphill drive. My husband spoke to someone yesterday that mentioned he needed to add a secondary trans cooler to the RV in order to tow the Jeep. Can anyone else provide guidance? We do not want to damage the RV transmission, but are not sure what we really need to do.

[tropical36]

colestat wrote:
We have a 2014 Forest River Sunseeker 3170DS Class C RV. We just got set up with a Readybrute system to tow our 2013 Jeep Wrangler Unlimited. We took our first trip with the toad 2 weeks ago from NJ to Vermont and the RV seemed to strain on the slightest uphill drive. My husband spoke to someone yesterday that mentioned he needed to add a secondary trans cooler to the RV in order to tow the Jeep. Can anyone else provide guidance? We do not want to damage the RV transmission, but are not sure what we really need to do.

What you have now with a tranny cooler should be adequate, if you're not exceeding the GCWR and even then, a little over shouldn't hurt, unless you're climbing the rockies all day long in extreme hot temperatures.
Having said that, you can't expect the rig to pull this weight without some straining and your best bet is to keep the rpm up into the hp and torque range, as you climb.
Besides, most modern transmissions have a heat sensor and will send the coach into limp mode if these internal temperatures are exceeded. Even then pulling over and confining your speed to 25mph in low gear will give you a 25% gain over the allowed GCVW, if that's the only factor under consideration and most likely is with what you have.
Now, I have to keep wondering with all the money that's wasted on junk by the manufactures, there isn't a tranny temp. gauge on a lot of these coaches and something else you might want to consider for your peace of mind and if for no other reason.

[jerseyjim]

Years ago I had the front seal replaced....(leaking tranny fluid) and while there, the shop told me it was most likely caused by overheating...even tho, they said, mine has the latest mods from the factory to avoid overheating. Gasket kit: $38. Labor $800. While working, I told them to put in a tranny temp gauge. So far, that gauge almost never goes over 160 degrees. So...overheating was not the problem. More likely a pinched gasket at assembly.
How heavy is your toad? And your V-10, like mine has a thermostaticly controlled fan...and it ROARS when engaged. Don't let that concern you.
An extra cooler can't hurt...but you must be careful: too MUCH cooling is not good.

[olfarmer]

I have a scan gauge on my MH, it plugs into the OBD 11 connection and will tell the transmission temp as well as anything else the vehicle computer is reading. Such as: engine temp, oil temp, gas mileage, voltage, and much more. So far I really like it. I got it on Amazon.com and it was not too expensive. You do need an external transmission oil cooler but chances are your MH already has one.

[jfkmk]

An auxiliary transmission cooler can never hurt if you're going to tow. Depending on the setup of your coach, it may already have one. All vehicles have a trans cooler that goes through the radiator, which usually isn't enough if you tow. An auxiliary cooler will start around $50 uninstalled, so it won't break the bank. Took me about 30 minutes to install one on my TV. Heat is definitely an automatic's enemy. Instead of a trans temp gauge, consider a smart phone app, combined with an OBDII wireless adapter. Around $20 for both and you'll get additional information such as engine oil temp and lots more. You can also read and reset fault codes if the check engine light comes on. It just needs to be a 1996 or later vehicle to have OBD II.

[Grumpy374]

colestat, don't worrry about it. I have a Forrest River Lexington 283ts, probably on the same platform as yours, E-450 with the V-10. When pushed, the rpm's will go up--supposed too--that's how power is made, and the V-10 is a high reving engine. Also, I tow a Subaru and use the tow/haul mode when towing. Makes a BIG difference when towing up and down grades. Your unit should have the same system, activated by the button at the end of the gear shift lever.
Grumpy

[oldmattb]

I agree with this. What sounds like strain may just be the engine and transmission doing what they should do - lower gear to allow higher revs, higher revs to allow more coolant flow and air flow, etc. The fan clutch can sound like a small jet under your dashboard. The objective measures are coolant temperature and transmission fluid temperature.

the bear II wrote:
A lot of RV'ers mistake the fan clutch doing it's job as the engine straining. As the engine heats up due to a climb or for other reasons the radiator fan clutch will engage. This causes the fan to spin which in turns makes a loud noise that many equate to a jet like noise. This helps cool down the radiator and transmission fluid.

The goal when going uphill is to not strain the engine and transmission. As the motorhome slows due to the grade and weight you need to down shift to lower gears to keep the RPMs up by using the throttle to stay at a speed that doesn't over rev the engine. You don't want the engine to lug so you need to keep down shifting until you find the correct gear and speed combination for climbing the grade.

Most Class C's already have a large auxillary trans cooler added.

You can't expect to fly up hills. Depending on the drivetrain setup and engine, 45MPH would be an acceptable speed down to 25MPH depending the weight of your motorhome and jeep on a 6% grade.

[ThorResidencyNe]

You would also need to install a transmission gauge to really know if the tranny is really having an issue. If it really is running hot, then you would need to address the issue with things like an extra electric fan on the cooler, a larger cooler and/or a transmission pan with extra capacity and/or cooling fins. You can also switch to synthetic fluid which can tolerate higher heat levels. Good luck.

[the_bear_II]

A lot of RV'ers mistake the fan clutch doing it's job as the engine straining. As the engine heats up due to a climb or for other reasons the radiator fan clutch will engage. This causes the fan to spin which in turns makes a loud noise that many equate to a jet like noise. This helps cool down the radiator and transmission fluid.

The goal when going uphill is to not strain the engine and transmission. As the motorhome slows due to the grade and weight you need to down shift to lower gears to keep the RPMs up by using the throttle to stay at a speed that doesn't over rev the engine. You don't want the engine to lug so you need to keep down shifting until you find the correct gear and speed combination for climbing the grade.

Most Class C's already have a large auxillary trans cooler added.

You can't expect to fly up hills. Depending on the drivetrain setup and engine, 45MPH would be an acceptable speed down to 25MPH depending the weight of your motorhome and jeep on a 6% grade.