I have been a long time reader of everyones wisdom but first time poster.

Vehicle is a 2001 4x4, 4.7L with a 45RFE.

I recently changed the tranny filters and added synthetic ATF4+ when done. I only added the fluid lost when the pan was dropped. I did not have anything on the magnet.

I have seen the RPM jump from about 1500 to 4000-5000 and back to 1500. There is no loss of momentum or harsh jerk when this occurs. This problem isn't often but its new.

I could not find a case in the Transmission Sticky that I felt applied to this.

Could a mix of regular and synthetic ATF cause this?

TC going bad?

Any thoughts?

 

No, the fluid could not do that. Full Synthetics and Conventionals are completely compatible with each other, it's just one is far more superior to the other.

It sounds like you are low or to full on fluid. Check the level. To do this start the truck cold, place the emergency brake on, run through all the gears all the way down and back up stopping 2 seconds in each and every gear. Park, Reverse, Neutral, 2nd, 1st then back up. Then come back to the Neutral position and leave the truck running. Open the hood and take the measurement and compare to the cold mark. Now this cold mark is just a mark, it is only to get you close not definitive. As long as you are close your ok. Now take it for a drive and get the fluid to full operational temp, about 15 miles. Stop and test again the same way just this time compare to the HOT line, the HOT line is the correct level and you need it there. Do not over fill!!!!!

Remember to have the truck on a level surface when testing.

Lastly, if you did not install the flat filter correct or insure the metal ring inside the port (I think that trans has one) then the fliter will only pull in air and cause that issue. You will have to drop the pan again and remove the flat filter. Ensure there is nothing inside the intake port and get a new filter from the dealer and re-install ensuring it is in there good and correct. Then re-fill using your fluid you took out that you saved after filtering it with cheese cloth. Then top it off.

 

While that seems like a pretty large fluctuation in RPM's could this be a bad TPS?

 

I have changed the TPS since the Tranny service. I don't know if the voltage is an issue, I didn't check it after it was changed.

The IAC is next on the list to be changed due to stalling only when the engine is cold. I will also clean the TB at this time.

I will check the fluid level, cold and hot. If needed, off comes the pan again. Did not know about being able to re-use the fluid.

Thanks for the inputs.

 

Update

I had the codes p1728, p1732, p1784 and p1791 within three days. The vehicle would not move in any gear after the last code. I walked home and waited for the wife to get home so we could tow it back to the house. After about 90 minutes we got back to the vehicle and I tried the tranny and it was able to be driven home.

A friend has a MATCO reader that pulled the p1791 which read loss of pump prime, this was after the vehicle was driven home. We dropped the pan again, changed both filters again. I found that the grommet for the flat filter was not seated. Made sure it was seated and filled the tranny with new ATF+4.

After a short test drive I pulled in only to find reddish fluid being flung by the belt. I found that the antifreeze is red in color, no help after working with red ATF. I changed the water pump and put antifreeze in and took it for a test drive. No fluid being lost and no codes.

Could the fact the water pump was leaking and the coolant was low cause the tranny cooler to not work as well as it should (tranny too hot), which in turn cause the codes I had?

I had to to work Friday when it was 19 degrees prior to the tranny and water pump work this weekend. I hope that I have fixed my issues by both of the things I did this weekend and can on cold mornings this winter.

 

Great thing to have fixed the problem...i would have thought that the rpms went to high for it to just be a tps or a vacuum leak. But glad you got it working again.