Engine/Transmission (1994 - 1998) 47RH Auto trans

[billjackson]

I've just installed a Mag-Hytec transmission pan and Isspro Trans Temp gauge on my 95 Dodge Ram (CTD). The probe installs in a port on the pan. I have several questions. What is the proper temperature operating range for the 47RH Trans? Proper temp coming out of the pump? proper temp in the pan? The Isspro gauge range is from 140 - 320. In normal unloaded conditions the gauge is sitting on the bottom stop. If I idle for prolonged periods it gets to about 150. What does that equal cominjg out of thje pump? Thanks for any help.

Bill

 

[rrausch]

The temp of the fluid out of the pump depends on how hard you are pushing it in non-lockup. If you're towing a load up a hill, unlocked, it will get pretty hot.



The proper operating range depends. The hotter the fluid gets, the shorter the life of the trans. This is especially true over 220 degrees as I recall. There was an article on this in the TDR magazine a year or so ago. At higher sustained pan temps, above 250 degrees as I recall, the life of the stock trans is drastically reduced.



The temp of the 47RH in my '95 hardly ever gets over 140 now, but I am running an ATS which runs cooler than stock. I forget exactly how hot mine got when I was stock, but I know it was over 155 running the same territory. I also have the Mag-Hytec and use the port for my sending unit. When I first got the truck I was seeing transmission temps of 280-320 in the pan. Didn't seem reasonable. One day I crawled under the truck when the temp was suppose to be 280 and put my hand on the pan--it was only warm to the touch. Yup--the sender wire wasn't tight and was making a bad ground. As soon as I tightened it properly the temps went down to normal.



Maybe someone else will post the # of the issue that transmission Temp article was in.

 

[Howard Durand]

Mine runs about 100 degrees normally and creeps up to 150 when I'm working it. I have never seen 200.



There are differing opinions on where the temperature sender should be located. I figure that measuring it in the pan tells me how well the cooling system is working.

As long as the high temperature oil coming from the TC is adequately cooled before returning to the transmission I figure it is OK.



I use synthetic fluid in mine because, I am told, it withstands higher temperatures than regular ATF without breaking down.