[elect]

Hey all, new member here.

Recently my truck has been throwing out the P0218 - Line pressure low and P0868 - Trans high temp. codes. Its a newer truck - 2013 Ram 2500 with only 54k miles. I've had no problems with it until now. It seems to run fine until the transmission temperature goes over 200 degrees and reached as high as 250 degrees. Now I know this is not normal after some researching on this forum. 180F seems to be the average for most people. Truck has not been ran since reaching 250 degrees. I do not want to cause any harm to the trans with the temp that high.

Can anyone shed some light what the issue may be? Any help would be much appreciated.

 

[N of 60]

The 0868 is the Low line pressure code. I would take it to the dealer and have your suction filter checked out and make sure it is sealed properly. That can cause foaming Etc. and causing your high heat. Fluid level is good?

 

[elect]

The 0868 is the Low line pressure code. I would take it to the dealer and have your suction filter checked out and make sure it is sealed properly. That can cause foaming Etc. and causing your high heat. Fluid level is good?

Thanks for responding. Yes fluid level is good and I should have mentioned that the fluid and both filters were replaced a few months ago.

Anyone have any more suggestions?

 

[N of 60]

Thanks for responding. Yes fluid level is good and I should have mentioned that the fluid and both filters were replaced a few months ago.

Anyone have any more suggestions?

What you just said is where I would start. The filter may have been tightened to much on install and has now cracked/split. Threaded nipple is plastic. Did you do the filters yourself? Dealer? OEM parts?
This was not happening before was it?
It would be nice to see your actual line pressure when driving to see if it flutters. Obviously it's not meeting your desired LP, that's why the code is being thrown.

 

[TransEngineer]

Check the cooler lines just in front of the trans and see if you have a Thermal Bypass Valve (TBV), which is an H-shaped block of aluminum in the middle of the lines. If you have one, then that is likely the cause of your overheating (TBV stuck shut). Check the temp of the lines once the trans is hot. If lines between trans and TBV are HOT, but one (or both) of the lines between TBV and cooler are cold (or at least, not as hot as either line between trans and TBV), then TBV is stuck and you'll need to replace it.

 

[elect]

What you just said is where I would start. The filter may have been tightened to much on install and has now cracked/split. Threaded nipple is plastic. Did you do the filters yourself? Dealer? OEM parts?
This was not happening before was it?
It would be nice to see your actual line pressure when driving to see if it flutters. Obviously it's not meeting your desired LP, that's why the code is being thrown.

Yes I replaced everything myself with oem parts from the dealer. I made sure not to over tighten the filter. It was fine after I replaced and drove it for at least 2 months with no problems. I may have to drop the pan and inspect it. Possibly replace the filters again for my own peace of mind. I will have to look into getting my line pressure checked

 

[elect]

Check the cooler lines just in front of the trans and see if you have a Thermal Bypass Valve (TBV), which is an H-shaped block of aluminum in the middle of the lines. If you have one, then that is likely the cause of your overheating (TBV stuck shut). Check the temp of the lines once the trans is hot. If lines between trans and TBV are HOT, but one (or both) of the lines between TBV and cooler are cold (or at least, not as hot as either line between trans and TBV), then TBV is stuck and you'll need to replace it.

Thanks for responding. I do in fact have the TBV. I will drive it later today and check the temperatures like you suggested

 

[elect]

Check the cooler lines just in front of the trans and see if you have a Thermal Bypass Valve (TBV), which is an H-shaped block of aluminum in the middle of the lines. If you have one, then that is likely the cause of your overheating (TBV stuck shut). Check the temp of the lines once the trans is hot. If lines between trans and TBV are HOT, but one (or both) of the lines between TBV and cooler are cold (or at least, not as hot as either line between trans and TBV), then TBV is stuck and you'll need to replace it.

Ok so I drove the truck until the trans temp reached about 190. I checked temp lines like you suggested with my infrared thermometer and here is what I got:
The top line going out from the trans to the TBV was 178. Bottom line to TBV 171. Top line from TBV to cooler 173. Bottom line from TBV to cooler 139. Does that sound about normal?

 

[Russ661]

If I'm reading all this right I'd say your situation is exactly what TransEngineer describes as a stuck TBV.

 

[N of 60]

The low line pressure code is being caused by? 2 issues?

 

[fufanu180]

That doesn’t seem to be enough of a difference to pin it down on the TBV. If the lines going to the TBV from the trans were consistent with each other and you saw a big difference from the TBV to the cooler and back then that would constitute the TBV being stuck closed.

You might need to see higher numbers on the transmission, temperature wise, and then check those lines.


Sent from my iPhone using Tapatalk

 

[TransEngineer]

Ok so I drove the truck until the trans temp reached about 190. I checked temp lines like you suggested with my infrared thermometer and here is what I got:
The top line going out from the trans to the TBV was 178. Bottom line to TBV 171. Top line from TBV to cooler 173. Bottom line from TBV to cooler 139. Does that sound about normal?

You might try running it just a little hotter to confirm (since I believe ~170°F is around the upper end of the opening range for the TBV), but overall that does sound like a stuck TBV. When hot, fluid should go from trans, through the TBV, to cooler, then back to TBV, through TBV, and to trans. If the return line to the trans (bottom line on the trans) is hotter than the return line from cooler to TBV, then TBV is not opening fully.

 

[elect]

That doesn’t seem to be enough of a difference to pin it down on the TBV. If the lines going to the TBV from the trans were consistent with each other and you saw a big difference from the TBV to the cooler and back then that would constitute the TBV being stuck closed.

You might need to see higher numbers on the transmission, temperature wise, and then check those lines.


Sent from my iPhone using Tapatalk

You might try running it just a little hotter to confirm (since I believe ~170°F is around the upper end of the opening range for the TBV), but overall that does sound like a stuck TBV. When hot, fluid should go from trans, through the TBV, to cooler, then back to TBV, through TBV, and to trans. If the return line to the trans (bottom line on the trans) is hotter than the return line from cooler to TBV, then TBV is not opening fully.

Ok so I ran the truck a little longer to 210 degrees. I checked the line temps again and I got something similar to the first time. Upper line from trans to TBV 176. Lower line from trans to TBV 156. Upper line from TBV to cooler 161. Lower line from TBV to cooler 134. Could the issue be something other than the TBV? Or based off these numbers a new TBV is in need?

 

[TransEngineer]

Ok so I ran the truck a little longer to 210 degrees. I checked the line temps again and I got something similar to the first time. Upper line from trans to TBV 176. Lower line from trans to TBV 156. Upper line from TBV to cooler 161. Lower line from TBV to cooler 134. Could the issue be something other than the TBV? Or based off these numbers a new TBV is in need?

Unfortunately I believe the opening temp is based on the return temp (from TBV to trans), and your last test was actually cooler (on that line) than the first one. So.... try again. Check the temps when that return line is 178°F or higher. At that point, the TBV should be fully open, so the bottom (cool) line between TBV and cooler should be at about the same temp as the bottom line between trans and TBV. If there is more than a few degrees difference, then yes it's time for a new TBV.

 

[elect]

Unfortunately I believe the opening temp is based on the return temp (from TBV to trans), and your last test was actually cooler (on that line) than the first one. So.... try again. Check the temps when that return line is 178°F or higher. At that point, the TBV should be fully open, so the bottom (cool) line between TBV and cooler should be at about the same temp as the bottom line between trans and TBV. If there is more than a few degrees difference, then yes it's time for a new TBV.

So I changed the TBV today and nothing has changed. Still over heating and low pressure. Any other suggestions as to why this may be? Could it be the pump not functioning properly?

 

[elect]

I am actually getting another code now. P0944 - loss of hydraulic pump prime. Its gotta be a bad pump right?

 

[TransEngineer]

I am actually getting another code now. P0944 - loss of hydraulic pump prime. Its gotta be a bad pump right?

I would check the filters first. Likely a misinstalled or loose filter.

 

[N of 60]

Post #2,4&10 But whatever!

 

[elect]

I would check the filters first. Likely a misinstalled or loose filter.

Post #2,4&10 But whatever!

I inspected the filters today they look good. No cracks or anything. But I will be changing them again next week.

 

[Lins]

Post #2,4&10 But whatever!

....... should be able to pull dipstick to look for excessive bubbles on it.