P30 Towing/Adding Hitch Advice?

[Schwarzkopf9]

Ok, so my plan is to remove the flimsy factory hitch and have a heavy class 5 hitch installed on my 1983 P30. Im going to install a brake controller and install a electric brake kit on my 2 wheel dolley and pull my Saturn outlook(front wheel drive, of course). My question I guess is what the P30 is capable of hauling? I had the camper weighed last year and its within limits. Ill be going on an 8 hour trip this summer and figured now is a good time to get ready. Not sure but, I believe the tranny is a turbo 400, it has the 454 chev so I assume this is standard. All input is welcome!

[Rickf1985]

The hitch should have the limits marked on it but it is usually 350 tongue weight and 3500 max load. The limiting factor in these ins the frame extension which is usually very poorly welded on. This is what you need to check before doing any heavy duty towing with an older rig. If the extension is butt welded then you might find that the extension is a different shape or even a different size like mine and the welding is incomplete and very poorly done. This could cause a bend in the rear frame or even a broken off rear frame. Pulling on a dolly is not so much of a problem since the load is linear but when the load is weight bearing on the hitch then you have issues with the frame being stressed. A class 5 hitch is a monster hitch and is several times more than you will ever be able to use it for. So really you are just adding a lot of unneeded weight back there. A class three hitch is just fine.


The transmission will be a 400 but you have to be sure you have enough cooling on it to handle the extra load. Engine also, if you still are running the original radiator I will bet you are going to have issues from the radiator being partially clogged. I changed mine to a newer aluminum radiator and it cools a LOT better.

[Schwarzkopf9]

Good tips Rick, Ill check into the frame extension on mine. Where about would you guess the welds would be on the 28 foot version of the P30? I did put a larger aftermarket oil cooler out front, I've been wanting to add a larger tranny cooler as well so now may be the time to do so. New radiator sounds like a big job, how long did that take you? Now that you mention it, I did notice my temp tick up a hair when I towed my boat going through the hills last year. Is it normal on these older engines to do that? My 08' Outlook temp doesn't budge a bit when I haul the boat with it.

[Rickf1985]

Radiator took me about a day to do but I had been in there before a couple years before that to replace the water pump so I knew what had to be removed and what could just be pushed aside. My AC was not charged so I could disconnect the condensor hose and just tilt that forward and sneak the radiator out from behind it. But on mine I also have some bodywork that does not come off and is permanent across the front so you have to work around that. If all of your front bodywork comes off that makes things a LOT easier. Towing a boat in the hills will definitaly make the temps go up just do to the extra load on the engine. Be sure your thermostatic clutch fan is working correctly. On my 31 footer the frame extensions are welded on just to the rear of the gas tank. Probably 4-5 feet in from the rear so yours should not be too far in. If it is not too far ion then you might possibly be able to fabricate side plates that will attach to the original frame mounting holes and not use the esxtension and extend the hitch mounts back. This can only be done within reason.

[circleD]

My 33' towed a 1/2 ton Chevrolet to Canada many times and across the U.S. with a square tubing on each rail that hooked to the tow hook area. There's alot of frame extension there but jas tandoms. It was a custom made set up but my uncle used it for years. He actually said he got 2 MPG better while towing. I'm sure it had to do with keeping the air off the rear. True story (aerodynamics).

[HamRad Mobile]

Good morning; 

You asked several questions. 

Yes, adding a large external ATF cooler really does help keep the engine temperature under control by getting the transmission heat out of the engine cooling system. 

The standard three speed automatic transmission in the P30 or P37 Motor Home chassis in that time period was the THM-475b or now known as the 3L80.  The main difference from the others in the THM-400 series is the straight cut gears on the First and Reverse gears to reduce the axial loading on the gear shafts and case bearings.  This improved the reliability of the transmission when used in motor home service. 

Something else that can be done to help when towing is the fitting of a slightly deeper aluminum cover on the differential to add some additional fluid capacity and a little better fluid cooling.  The same thing can be done with the THM-475b transmission pan to increase the ATF capacity by about two quarts and add some additional cooling.  The fitting of a Derale or Hayden ATF thermostatic control valve can help with possible over-cooling in the cooler months and keep the transmission operating at the optimum temperature.   

Anything you can do to help control subsystem temperatures will improve reliability and component life expectancy when towing. 

Enjoy; 

Ralph 
Latte Land, Washington

[Schwarzkopf9]

That's a whole lotta stuff I never considered! I look into that.