Hello,

I'm looking for some advice, please... I have a 2002 F250 7.3 with the electronic 4-speed automatic transmission and with about 88K miles. I use it (infrequently) to pull an RV trailer rated at about 5500 lbs. Recently, while pulling the trailer, I noticed the overdrive light flashing. I used the Forscan viewer to get the message, which is included. Some text from the message is: "Torque converter slip is greater than expected" and "may be caused by: internal mechanical/hydraulic failure". I do notice some difference in the way the truck is shifting through gears 3-4. It's like it drops from 3 to 4 then quickly bad to 3, and then back to 4. I wouldn't describe the behavior as alarming and eventually it settles into OD and everything seems to be fine. This type of behavior occurs both with and without the trailer, and it is happening now with pretty much every drive.

What would you do about this type of issue?

Thanks very much!

 

Is the transmission fluid topped off to the full mark? Is it in good condition...translucent pink with no tint of brown?

 

Thanks for following up. I will check that as soon as I can. I've been researching the right way to check the fluid and I think I know the procedure. I just need to get out there and do it, which includes having time to drive the truck so it's at proper operating temps. I'm hoping it's a fluid only issue. I will follow up when I have more information. Thank you.

 

Hello again, I checked the transmission fluid with the truck cold just to look at its color. The fluid does indeed look pink. Honestly, I cannot be certain there is no tint of brown because I don't know what the fluid looks like other than what I pulled-up from the dipstick. I don't think there's a tint of brown but I'm not certain.

I drove the truck (without the trailer) about 10 miles over 20 minutes and the overdrive light did not flash. I checked the fluid when I stopped (at my office parking lot). The level and color seemed to be what was expected. After about 4 hours, I checked the fluid again... what was unexpected is that the fluid level was still at the Hot level and not at the Cold level as I expected. My first cold check was with the truck parked in my driveway at an angle and I was just evaluating color and not level that time. I drove the truck back home (10 miles/20 minutes) and no OD light flashed.

I'm not sure I can conclude anything from this activity... I no longer have evidence of a consistent error being logged. I'm unsure about the fluid level now (is it too high?) Maybe my checking procedure was bad?

I'm not sure what are good next steps. Any recommendations most appreciated. Thank you.

 

To properly check the transmission fluid, get the truck up to operating temperature, park it on level ground with the motor still running, pull the dipstick and see where the fluid level is...note, I typically let it set idle for a couple minutes to let the fluid settle on the dipstick to get a more accurate reading. Relative to the code, I know it sounds weird, but I would pull the VSS sensor on the top back side of the rear axle pumpkin. It is a magnet that takes readings off the ring gear and can get fine medal shavings on it causing inaccurate readings. If so clean them off really good...

 

OK, thanks. My check procedure was indeed bad/incorrect. I completely forgot to do what you described even though I did some research and understood that is the procedure to follow. I will recheck again soon and report back. I will take a look and see if I can find the VSS sensor, too. Thank you!

 

Hello again. I checked the transmission fluid again using the correct procedure, although I didn't let it idle very long before pulling the dipstick. And, I'm not sure if the temperature reached anything within the operating range. I don't know the acceptable operating range. I have a trans fluid temp gauge which starts at 140 but the needle never made it that high. I usually don't see that needle move very often... it mainly moves when pulling the trailer, driving for quite a while, and when fairly warm to hot. And even then, the needle was not too far past 140.

Back to the level... my reading showed fluid only about 1/2 up the cold section. My feeling is that I should add some fluid although I'm not sure how much. I thought I'd start with 1/2 to 1 quart and then see if the code is thrown. Incidentally, the code is not being triggered on my recent drive which was, again, without the trailer.

I'm still focused on the fluid and making sure its level is OK. I have not investigated the VSS as previously advised.

I'd appreciating knowing what you think, please.

Thank you.

 

Since your fluid level readings have been inconsistent I would suggest checking it one or two more times to try nailing down a reading you feel comfortable is accurate. Another suggestion is to scroll through the Forscan PID list looking for the speed sensors. I'm sorry I can't recall their specific names at the moment, but a little time and deductive reasoning should get you there. Plus maybe someone else will remember and help out. With the the PID's live streaming during your drives you might catch an episode with Forscan that could help figure out what the problem is.

 

Thanks for helping. I'll check the level again a couple of more times now that I understand the procedure. I'm not all that familiar with Forscan. I have the FORScan Viewer on my iPhone. Are you referring to the Windows based version or something else? I am happy to look into that for more real-time monitoring. Thank you.

 

No I use the Android version myself. You my want to check out the stickies section. There is a pretty thorough tutorial there on all things Forscan. It can show you all the trucks it can do.

 

Yes, thank you. I understand, I've seen that section. I will get the version for iOS. I've been wanting to monitor in real time for a while and this is a good time for that. While looking for the FORScan section, I did browse the section on F250 transmission problems. There was a color index included somewhere in there. From that range of colors, I conclude by fluid is still good. It doesn't match the new color but it does match the second color which I'm OK with. Thanks for your help.

 

Does your cruse control work?

 

Yes, it works. No problems with cruise control. In fact, really no other problems other than what seems to be this intermittent code that's triggered when pulling the trailer, which I don't do very often. Right now, without the trailer, no code is being logged, although I don't drive the truck all that often, either.

 

Just to bring this to some closure for a while, I have checked my trans fluid level a couple of times when the truck has been warmed-up. The fluid level is low. My first change will be to add some fluid (not sure how much yet). My goal is to get the fluid level to the proper level when hot and then I'll test again with the trailer, although that last test will probably be a while since it's getting pretty hot and humid for camping around here. I have no answers for why the fluid level is low, though. I don't see any leaks. The code being triggered is a relatively recent event even though towing the trailer is not. I will monitor things and share any update that may be worth sharing. Thank you all for the help.

 

The transmission dipsticks are pretty close to the engine oil dipstick in how they read. Meaning for instance if say 3/4 of an inch = 1 quart of engine oil, then 3/4 of an inch on the transmission dipstick is equal to 1 quart of fluid. If that makes sense and helps at all. Good luck, let us know if you have any questions.