Have searched to no avail. Tranny has developed a very short rumble when downshifting from OD on a hill or under load. Upshifts fine. Anyone here had this? The rumble as best I can describe, sounds like the rumble strips on the freeway. Need an opinion before I let a shop look at it.

 

Finally got some search hits. COP's, old fluid, TC, or on the way out, seems to be the concensus. Oh 1 more. Add 2 bottles of friction modifier. For me, plugs at 139k, just did the COP's at 170k. Bought the truck used, so I don't know about tranny fluid changes. Guess I could pull the pan to see if i find the little yellow plug. Any others had any luck with the modifier?

 

Put 2 bottles of the friction modifier in tranny 4 days ago. Rumble dissapeared.

 

Never heard of friction modifier in the transmission. You should change the fluid. The 2005 does not have the torque converter drain plug, so you need to take it to a shop or follow the procedure posted somewhere on the site that tells you how to disconnect the trans cooler line at the radiator and pump it out 4 qts at a time and adding 4 qts at a time. Do a search and you will find the procedure.

What I do is just dump the transmission pan and refill every 20k miles or so to keep the fluid fresh.

 

I bought the truck used with 170k on the clock. Have no idea of the service records on the tranny. The guys that have built trannys for my family for years said I would regret the fluid change, not knowing if previous owners did it. You can get the modifier at any dealer for 5 bucks a bottle. It cured my problem so far. I haul and tow every day. Thats what I buy Fords for. The last Chevy I bought only lasted 1000k before the engine popped. Taught me a lesson.

 

Is the friction modifier a transmission product or is it the same friction modifier for the rear?

 

That's incredible!!! 1000k miles indeed. That's a million miles,ya know.

 

new trans fluid has the modifier in it already the fliud in his must have never been changed his fluid is breaking down