I have an 04 screw lariat 5.4 4x4 and never had a single problem until yesterday. I put it in reverse (on flat ground) and it seemed as it it was slipping. didnt think much about it until i tried reversing up my driveway and it just didnt want to catch. It would move about a foot, then stop, then a little more and so on. Im pretty sure its slipping but I was wondering if anyone could help me or if there are any other suggestions on what it may be. Please help, im not very educated on this tranny. Also, dont know if this helps but the tranny has never been serviced either and I have 120K on the truck, mostly highway. Runs strong in drive also. If anyone has any input please help. I dont have a lot of money at this point and I need my truck to pull my work trailer. thanks guys.

 

You do know that if you tow with the truck, you are supposed to change the tranny fluid every 30k?

Pull the dipstick, look at the fluid and smell it. If it's not red and/or it smells burnt, you need a rebuild.

 

My 04 150, 5.4 tranny shudders if I am climbing a small hill and it downshifts into a lower gear at between 40 to 50. Any other time it's fine and if I accelerate I can go on through it. It does the same with OD selected or off. I have heard that there may be a speed control cable that could be a problem? I have no clue. I have 158,000 miles on the truck and had the tranny serviced 25K miles ago and everything looked good. Does this cable exist or is someone blowing smoke?