A couple months ago my transmission in my 02 F450 diesel let go. I replaced it and along with it I installed the 31 row dorman 6.0 cooler. I flushed the cooler in the radiator along with the lines with transmission cooler cleaner and pushed air through with an air gun to make sure all the flush was out. For the first month it was all good. Transmission works good drive it to a few jobs never worked it hard basically used it as a daily driver. I got a hot shot load down in Des Moines which is about 6 hours one way. When I got on the interstate I run it up to 70 and wasnt really paying attention when I noticed a while later it was at 220 on the transmission temp! I backed off and it wouldn't come down until I was under 60 and would run at 180ish at 55. I got down there picked up the load and started headed home. Here's what it does. It very gradually increases in temp little by little. Maybe a degree every 45-60 seconds. It doesn't really like to come down unless I duck off onto a ramp and let it idle down at which it drops at a pretty fair pace. I got frustrated and thinking maybe the cooler in the radiator is still plugged I stopped at a parts store and grabbed a tube cutter and some hose and bypassed the cooler in the radiator. It's acting exactly the same. Maybe the bypass on the side of the transmission is acting up? I'm at a loss and this transmission has maybe 1000 miles on it. Any ideas?

Thanks

 

Did you replace the torque converter?...and if so, with what? What unit did you replace the transmission with?...a regular rebuild from the local shop, or one from Ford? Pull the transmission line up near the radiator and direct it into a bucket...when you start the truck, you should get about a gallon of transmission fluid in one minute. If you aren't, then you have blockage somewhere.

 

Yes they shipped a torque converter with it. Which is working fine as far as I can tell. A hair under 2000 rpm at 60 was what it did before the previous transmission started to go

 

Where did they come from? Is it a billet or stock torque converter? With a 3.73 gear out back you should be a hair under 70 at 2,000 rpm, but being a F450 you might have a 4.10 gear out back.

 

See if the bypass tube on the passenger's side of the trans is getting hot. There should be no flow through the bypass, so it shouldn't get hot.

You can get a bypass rebuild kit from Summit for about $25.

 

It has 4.10 gears in it and I assume it's w stock torque converter

 

Monster transmission is where I got it from

 

I seen that. I've also seen bypass delete kits for about the same price. I haven't checked to see if it's hot yet. Figured I'd take the line off and see if it's back feeding out the return

 

So I have an update. I finally pulled it apart last weekend(been basically living out of my Kenworth last week) and completely flushed everything. Coolers, cooler lines, bypass. Pulled the bypass apart and cleaned it. Put everything back together and did flow test before and after the cooler, had good flow. Put it back on the road and it hardly gets a above 120 without a load now. I had my 1000 gallon fuel caddy on it when the storm hit and it got up to 136 pulling that thing through 12 inches of wet heavy snow so I'm thinking I had a chunk lodged somewhere that came loose?