dandrhill

Providing an update. We now have almost 2000 miles on our 2015 Cherokee Trailhawk with about 500 miles towing. So far we are extremely pleased with the choice of the Cherokee as a toad. It tracks well and is easily pulled by our 2003 Winnebago Journey DL with 300hp Cummins. The car is also much more comfortable than our previous Wrangler and is replacing both the Wrangler and my wife's Ford Escape as her primary ride. We had hoped for somewhat better gas mileage, we are getting around 20 mpg in town. Also the auto stop start function takes some getting used to. As I said in my earlier post, the install is more complex than the Wrangler but probably no more difficult than other vehicles that require removal of the front fascia to install the base plates. You do need the proper tools to do it yourself but any good shop will certainly be equipped for the job.

We have just begun towing a 2015 Cherokee Trailhawk. Used Blue Ox baseplates with an Aladdin Towbar. Also used the Blue Ox diode kit for the lights. Since our MH has separate Turn and Stop lights, I installed Roadmaster HiLite 3 wire to 2 wire Stop and Turn converter. The baseplate install on the Cherokee is significantly more involved than the install on the wrangler. You need to remove the front fascia and bumper from the Cherokee and be able to cut some fairly thick steel that is part of the bumper mount. I am pretty skilled and have the right tools and the job still took about 5 hours. Of course part of that was me being extra careful not to scratch my wife's brand new car that had less than 250 miles on it. At this point we have only towed about 100 miles but it seems to work extremely well. Cherokee tracks good and seems to be less impacted by cross winds and trucks passing on the interstate than the wrangler was. Shifting the transfer case in and out of neutral takes some practice but once you learn how it works seamlessly. A couple of additional items. Not all Cherokees can be towed 4 down. Only the ones with the 2 speed transfer case can be towed with all 4 wheels on the ground. That means it must have either Active Drive 2 or Active Drive Lock (Trailhawk model only). Cherokees with Active Drive 1 can only be towed on a trailer (all wheels off the ground).

Your Allison transmission has sensors to monitor its operation and detect possible faults before leaving you stranded on the side of the road. For example, it knows the speed of the input shaft and the gear currently selected. With this information, the computer knows what speed the output shaft should be turning. If the measured speed is not close, the computer will declare a fault and turn on the “check transmission” light. It will also put the transmission in “limp home” mode and lock the transmission in the last known “good” gear. It will stay this way until the next time the transmission passes its built in self test when the engine is started. I had a similar experience to yours while traveling down a long grade on I64 in West Virginia. We had been traveling for several hours through the mountains using the engine brake and cruise control to when suddenly the “check transmission” light came on and the transmission locked in high range (6th on our coach). We had just started down from the top of Sandston Mountain traveling at about 65mph. Fortunately there was not much traffic and I was able to use the service brake to get us slowed down. At that time I had no clue about the “check transmission” light or the existence of a “limp home” mode. I turned to my wife and asked her to dig out the books and get on the phone. The Allison technician told us that it was either a “soft fault” in which case it would clear itself the next time we started the engine or it was a “hard fault” in which case the bus was not going to move until it was fixed once we turn the engine off. Since it was nearly 11:00pm we decided to stop for the night at the Walmart in Lewisburg, WV and see if things got better in the morning (we got sideswiped by a WM truck in the middle of the night but that is a different story). The next day we started right up, the fault had cleared, and had no more problems on our trip. When we got home we took the bus to our local Allison repair shop. They determined we had two solenoid valves in the transmission that were in the process of failing and needed to be replaced. Our Good Sam Extended Service plan covered most of the cost and today, after 3 years and nearly 20,000 additional miles, it seems to be working as good as new.

Sorry I didn't get back sooner. Hope the trip is going well. Make sure you get down to the tidal basin and check out the cherry blossoms. Thanks to the mild winter they are quite spectacular this year. The 13 foot clearance on the bridge is the minimum clearance above the road bed. For an arched bridge, that is at the right hand edge of the right lane. The clearance increases from there until you reach the center of the arch. Above the center of the roadway, the clearance will be significantly more than the minimum. I haven't driven my coach through the GW parkway but expect that if you hug the center when going under the overpass you should not have any problem.

Personally, I don't find much of DC to be big Rig friendly. We live about 50 miles south and whenever we travel north we leave very early in the morning to avoid the traffic. The GW Parkway is mostly 4 lane divided but has overpasses that are built using stone arches that force you to crowd the center of the road when going under. I think they are all more than 13 ft, they just feel smaller. There is also a section a couple of miles long that is going through Old Town Alexandria. Many stoplight but no overpass there. Parking will be a problem. Many of the places you will want to visit are in town with limited parking. If it was me, I would rent a car or stay in a park and take a bus to the Metro. Cherry Hill Park is just outside the beltway (I495) on the north side of town. They often have a shuttle service to the closest metro. To answer your second question, other things within 200 miles, Shenandoah National Park is less than 100 miles west and Colonial Williamsburg is about 150 miles south and east. These are among our favorites and are Big Rig friendly. There is ample info on the web for both these places. Hope you enjoy the visit. The Cherry Blossoms are a little bit early this year because of our mild winter.