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47rh overheating???

5K views 14 replies 6 participants last post by  deathrod 
#1 ·
My setup is a ve pump 12v in a 3200 lb 1930 model a. I recently swapped a 518 to a semi built 47rh. It ran great for a few thousand miles then one day on the freeway the trans started to smoke. It runs great when it's cool but once i go on the freeway for a while then get off and take off from a stop it feels like the tc is slipping almost like its in a high gear when it's not.

The only thing I don't have a gauge on is the tranny of course, but I drove about 10 miles right now and checked the temp with an infrared gun.....pan was 190, cooler lines were around 150-160 going in about 20 cooler coming out. It has 2 coolers and never had temp problems before and should never with it only being 3200 lbs. 190 in the pan with a short trip and no load seems hot.

The fluid looks a little burnt but nothing excessive, it has plenty of fluid, any ideas?
 
#4 ·
transmission temps

There are two cooler on the transmission on being the engine cooling system and the other up front . I was told the most accurate way was out of the transmission to the cooler not in the pan . Most of the heat comes from fluid coupling and drops when in lockup. Never installed a temp sensor in my transmission as I did not expect to last this long lol . Then install a 5 or 6 speed . Or you sure the converter is staying lockup up in overdrive or third gear . Jim
 
#5 ·
The way I have it set up is I lock it up when its in overdrive. Both od and lock up work......as there is no fluid coupling it should run cooler in lock up but thats where I seem to have my problem. Its not slipping at speed either. After driving a bit in od locked up it seems to get hot. The pump is working, I checked that....im kinda thinking there a problem in the od section even though it works fine.....
 
#6 ·
Is the cooler clear of grass bugs ect. One things that I have not done but have been told to do is remove the check valve in the cooling line . If it goes bad you will have a or could have a bad day. I was told to remove it and as I all ways do to neutral before I go to any gear when I first start the truck . Never let the truck idle in park and all ways use neutral and set the line lock on brakes . I would think that in overdrive the mechanical leverage would cause the transmission the run a little hotter than drive which is one to one . jim
 
#7 ·
I have custom cooler lines so no checkball to deal with. Stock these things dont pump in park so yes neutral is better, but ive taken care of that too. I think im gonna have to yank it out again and go through it......ahhh
 
#8 ·
manual valve

Yes I know I should have replaced the manual valve or better yet a valve body but I hate the automatic so I was just waiting for it to go out and replace it with a manual . The reason it lasted as long as it has and with the extra torque is these forums . All band aids I am sure but it worked so for Jim
 
#9 ·
It has been a few months and tranny has been in and out a few times....tc has been rebuild and it was fine. Nothing wrong in trans/vb per myself and 2 trans builders. Drove it about 10 miles and pan was 220....cooler return line was 140ish. The first rebuild the front clutch pack was smoked. It doesnt seem to slip and clearance is within spec for the clutches. I suspect its something to do with front clutch......but cant find a problem. Ideas???
 
#10 ·
Just rebuilt the front section of the trans again (front and rear clutch packs) and went back to stock configuration. The trans runs and shifts great, pan still around 220* under light load. Im going to just run it and see how long it runs. Anyone have a laser temp gun to see what their pan temp is after normal unloaded drive?
 
#11 ·
You need to add some transmission coolers. Do not collect $200 (unless it is to pay for parts). Do not pass go. Go directly to the parts store and get some 1/2" cummins compatible transmission coolers. 220 degrees will fry your transmission pretty quick.

 
#12 ·
Thats just the problem.....it has good coolers and the fluid returning to trans from coolers is 115-140 range when pan is over 200....thats a big drop in temp so coolers are fine. Im pretty much tapped on ideas, nobody seems to have any other ideas on what it could be.
 
#15 ·
Yes they were checked as one of the first things...we suspected coolers or pump. The guys at trans shop unplugged the return line and started it in neutral. It was supposed to pump x amount quarts in x amount of time. It exceeded what it was supposed to pump. It ran a A518 with no problems for about 10k miles......a locked up tc should lower temps. Something else is wrong
 
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