I have a F-150, 5.4, 2007. First, will the transmission send a signal for the check engine light? I heard from a respectable mechanic, it does not.
Here is my problem. I started getting bumps when it was time for the trans to shift down from OD. I could push through it and make it change. I took it to Ford and they come up with, cylinders 1,2 and 5 are dropping down to -20%. Recommend replacing the coils. Did that. Truck seems to run a little better but the shifting problem is still there. I called into a car talk show in the area and he suggested to have a mechanic check and diagnos the trans. I guess it is two different systems in some way when doing diagnostics. So, he said it's possible the solenoid or maybe more need replacing. I like my truck and I try to take good care of it. But I'm loosing faith in the Ford dealer. Actually I'm loosing faith in a few mechanics around here. I have a tip from neighbor to check another one out. I will today. So I'm thinking I may have to replace a solenoid or solenoid pack. This part is new to me. My old truck, 1992 had a stick, I miss that one. Fun to drive and is still running with 400,000 miles on her. Sold it to a friend.
Ok, there it is. I see there is a transmission mechanic here. I would like to hear what everyone has to say about this. My truck only has 146,000 on it.
Thanks.
Larry
Lewis County, Wa.

 

I'm not a transmission mechanic, but I can take a stab at it.

Certain failures in the transmission CAN turn on the Check Engine light. Most transmission problems will flash the OD OFF light.

I've seen problems like this before. I've always fixed them with new coils AND new spark plugs. It is almost certainly not a transmission problem.

 

Thanks Mark. The plugs were changed not long ago, maybe three months. Next Monday it's going to another shop that was recommended by a neighbor. I talked to him today and he sounds like he knows what he is doing. We'll see. I will report back so others have the info. Thanks again.

 

Were the plugs changed at the same time as the coils? Were any coil boots changed? Putting new plugs in without changing the boots is asking for trouble if the old plugs were misfiring. Why? Carbon tracks form on the old plugs when they are so worn out its easier for the spark to jump outside the plug than across the electrodes. When this spark jumps between the boot and plug it vaporizes some of the rubber and forms a conductive trail on the plug and boot. Replacing just the plug leaves this trail in the boot and the spark finds it soon after. Now that is has found it a new trail has formed on the new plug. Plugs and boots should be replaced together.

 

I'll bet ALL my chips at once that both @Mark Kovalsky - & - @70f100longbed hit the bulls eye on first shot.


I have no problem with your taking it your neighbor's recommended mechanic - but if he says anything different from Mark & longbed, (and I'm betting ALL the chips I'll win on the first bet above) he probably WILL. Your story tracks my experience with my 5.4 to the "T" when slight intermittent misfires begin to develop around the same mileage. Coins in my ash tray would jump/rattle randomly under light load just before downshift out of OD. Same crappy recommendation from idiot FORD dealer, same results. Local 'respected' Transmission Mechanic even drove it - and diagnosed it as the transmission!!! (Either T/C clutch or valves he said, recommended complete transmission rebuild.)


My problem turned out to be NOTHING but a properly done, clean spark plug job (like longbed is recommending). I posted my after-thoughts on that here: https://www.ford-trucks.com/forums/1...l#post15819897


Also, the learning process in THAT lead me to 'delve' deeply into OBDII diagnostics with a good scanner tool. Through that experience I learned that FORD provides the most complete reporting of any manufacturer out there, and there are lots of operating diagnostic conditions reported via OBDII.

You might 'INSIST' the mechanic provide YOU a "MODE 06" diagnostic report on misfires. It will show the number of misfires (By cylinder) during the Current - AND - the last ten (10) drive cycles. That report INCLUDES misfires that are below the DTC threshold, so it is most valuable.


You asked about the Tranny setting codes. Yes, there are Thirty-One (31) Obdii parameters available for the transmission, many of which will set DTC if they are out of spec. (Including interesting things like line pressure readings, Torque converter slippage in RPMs, shift times (in milliseconds) between each shift, Calculated gear ratio, RPM drop in upshifts, and RPM rise in shiftdowns - and many more.)


I think if ANY of this were the problem, you would have a DTC. I believe Mark & longbed are dead on.