It is best to drop the tank and install the new updated fuel pump. It is really not all that hard. First try and run as much fuel out of the tank as possible. You just get a good floor jack, 2 if you have them, A large portion of 3/4 plywood. Place the plywood on the jacks and raise them up to the bottom of the tank. Loosen all the bolts holding it in place. You may have to use WD40 or rust buster and let it set for a while. Once you take the straps off and bend them away from the tank. Lower it down so you can take the fuel inlet hoses off and take the fittings loose from the fuel lines. This takes a special tool. Once every thing is off then drop the tank down, take out the old pump, Install the new pump, Splice the wires together as shown in the new pumps installation guide. Raise tank up so you can reconnect the fuel lines and fuel inlet hoses. Then raise it up and reconnect the straps and tighten the bolts. Poof you are done. Takes about 3 hours.
The reason these go bad is that the pump uses the fuel to cool it. If you constantly run the tank below 1/4 it will get the pump hot and it will eventually fail.
The new pumps are much much better than the old ones.
Other things to think of also. Make sure your Propane sensor is turned on. Some coaches need this on before it will allow the propane to flow. Take the air out of the system by lighting a burner on the stove.
Gear vendors expensive???
Well lets see - rebuilt 700R 1000 bucks, Torque converter 300 bucks, Crossmember mod 300 bucks, Linkage mod 100 bucks. If you have the parking brake on the trans big bucks!! Wiring mod for lockup converter 100 bucks. Drive shaft mod 250. And when you are all done you only have 4 speeds and they recommend you don't tow in overdrive whereas with a Gear vendors you get 6 forward speeds plus you can split gears going up hill. It's cost is around 3200 bucks.