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Transmission Hot Roger W 9-4-02  
92 33 ft Chev 454 over drive transmission that runs hot when climbing long grades. The temp sensor is located at the trans cooler out line and shows 140 to 180 when running on the level. Any steep grade will cause the tempature to rise fast and on long grades can reach the 270 - 280 mark. It has the extra cooler with a second fan. Slowing down and running in lower gears makes no difference. Is the torque converter causing the heat? Any suggestions on fixing this problem.
Re: Transmission Hot RV Wizard 9-4-02  
I have heard that if you turn your dash air off it will help. I also hear of a guy that installed a small 12 volt pump off the water tank and misted the radiator by use of a switch for long uphill grades.
Re: Transmission Hot Joe 9-4-02  
Your transmission has a "Lock up" convertor. When it is in "Lock up" the flow of oil to the cooler is increased. It is possible to have a problem with the convertor, but first you need to find a transmission shop that has a flow meter that will measure the flow from the transmission to the cooler. I have seen MANY MANY coolers in the radiator fail causing the flow to be reduced and so it doesn't pass enough oil through to the aux cooler. First things first. Also make sure your radiator is fully topped off, as the engine coolant passes through the radiator core first and passes over the trans cooler last so if the coolant is just slightly low not enough coolant will pass over the trans cooler. The cooler must be fully submerged in coolant for the heat exchange to work properly.
Re: Transmission Hot chuck 3-18-03  
Are you aware of recall on some 92 chev trans. mine went out in texas about 5 yrs ago. and was replaced by chev n/c i had,and still have 92 southwind chev 454.. at the time i had about 45 or 50 thou on it.. chev said tran had been extended to about 75 thou mi. dont hold me to dates and mileage but trans was replaced.. also was told not to tow in o/d at any time.now have 101000 on rv and towing 002 honda crv...just got back 4000 to tx and back
Re: Transmission Hot Roger W 9-4-02  
Thanks for the suggestions. I previously had the radiator tested and rebuild with a desert core and now stays normally at the thermostat 190 and never above 220/240 on the grades. I believe the trans cooler and small lines will not pump enough oil for the fast heat increase on hills. I smell hot trans oil at the top of a grade and feel my guage is accurate. It will cool fast in the lock up position going down hill for a few miles. It shifts up/down fine. Motorhome has only 25k miles and I added the Banks exhaust unit and Jacobs ignition. Any experience with over sized trans pans or heavy duty torgue converters? What is normal tempature worst case for this trans if 270/280 is considered oil break down point?
Re: Transmission Hot Joe 9-4-02  
I would think 250 is a maximum temp for your trans. When a radiator core is replaced, the tanks and trans cooler are reused off the old radiator. We never recore radiators unless that is the only choice. We go with complete new radiators. Most radiator shops have no way of testing a trans cooler. Some trans shops have a flow meter that is placed on the vehicle and then driven until the problem shows itself. There are special fluids, deeper pans, pans with cooling tubes in them, and what is called a "RV" convertor. I have worked on many newer motorhomes that pull trailers and haven't encountered your type of problem. You should probably take your trans out of overdrive on long hills. Get it flow tested.
Re: Transmission Hot Roger W 9-5-02  
I will start by replacing the trans pan with the over size aluminum pan. There is the tube type with less oil capacity, B&M 3 qt with fluid pick up extension, and PML 3.7 qt with stand offs to hold the filter in place. What is the best?
Re: Transmission Hot Joe 9-5-02  
Either will work, maybe the one with the tubes is your better choice. I'm not sure that will solve your problem as we don't want to wind up with the tail wagging the dog. If your coolant is 240 on a long pull, it won't do much cooling for your trans fluid, or is it your trans is so hot, it is running your coolant temperature up to 240? The fact that you are smelling hot trans fluid bothers me. Your vehicle was designed to handle the load with at least some cushion. Yours isn't doing something right. Adding things may be only a temporary band-aid.
Re: Transmission Hot Roger W 9-6-02  
I agree with you Joe but not sure that the GM P30 chassis was design for much more than a step van for Mac Tools. The new workhorse chassis, 8.1 engine and Allison trans tells me GM finally decided things were out of control with the motorhome mfg adding more slide outs, basement storage, and accessories. I will add a larger cooler and a second temp guage on the return line to monitor the best cooling arrangement. Several Web sites talk about heavy duty torgue converters as the answer and that may be needed.
Re: Transmission Hot Jack 9-9-02  
Roger, after be frustrated with high trans temps & several fixes I found the right combination. B&M deep alum.trans pan, B&M SuperCool trans cooler with thermo. controlled fan mounted at the grill not set back as far as the factory mounts it. I then realized that the Banks header system (crossover pipe)was just 2" from the bottom of the deep pan, so I installed 2" wide header wrap starting from where the header tubes come together on both sides. Finally had the system flushed not just drained & put in Mobil 1 synthetic trans fluid. Lowered temps by at least 80 degrees or more. I have a '91 H.R. Imperial 33'ford 460 f.i. E40D trans. with Banks Trans Command.
Good Luck..Jack
Re: Transmission Hot Joe 9-6-02  
Well Rog....Last Augest I towed my Chevy Avalanche towing a 21ft Bayliner boat from New Jersey to Oshkosh Wisconsin, to Memphis, and finally to Florida with my 34ft Motorhome. It never ran temps out of range. I downshifted (had no choice) on long hills. I have only what came on my motorhome new. So I figure my motorhome weighs 11,000lbs, the Avalanche is 6,600lbs, and the boat and trailer is roughly 2,300lbs. All that weight, and all those tires on the ground...thats a lot of drag and the 454 pulled it fine.
Re: Transmission Hot R Wiekamp 9-9-02  
Joe, are you monitoring the trans temp? I do fine on small grades under a mile or so but the 6 to 8 % grades that extend for miles are the problem.
Re: Transmission Hot Joe 9-10-02  
Yes, I drive through Ky and Tenn. with some hills 10 to 15 miles long. There is one in western VA that is 22 miles at 6%. I have had my motorhome up that with a tow car on the back. Now, I'll admit that I'm only doing 45mph in second gear, but it doesn't run hot. My trans never goes above 245, and the engine never exceeds 215. Everytime I have encountered a problem like yours something mechanical is wrong. Like I said before, 240 degree coolant won't do much for cooling hot trans fluid.
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