I took a 5.4 triton out of my 98 F150 and used it to replace a bad 4.6 in my 97 F150. Two days later, no forward gears...
Help...

 

Did you keep the 4.6 tranny in the 97 or swap the 5.4 tranny also. Read somewhere in these threads that a 4.6 tranny cant take the extra power or something. Read through this thread, theres alot of good info.

https://www.f150online.com/forums/ar...p-notes-3.html

 

A 4R70W can handle a stock 5.4 easily, especially a non-PI which the 98 is. The only difference between the 4.6 and 5.4 versions is the torque converter, and a 4.6 TC will work on a 5.4, just not optimally.

 

That was my impression as well. I was also told the T/C called for the same part #?? Am I just to assume the tranny lost all forward gears in 2 days by pure coincidence??

 

Have you checked the OBD2 for codes with a high end scanner that can read Ford transmission codes?

 

The mechanic that did the work did. Could not figure out the problem. I just know that $3300 later I am still parked. If a new tran is the answer, fine! I'm so far in, I just want the truck to run. I just don't want to burn another tran up in 2 Days. Also, it felt like it was kind of floating before catching gear, right before I lost all forward gears, I am hearing clutch plates???

 

It was my understanding that the T/C calls for the same part #, is that not correct

 

I thought they had 2 different stall speeds.

 

Two mechanics and now Orieleys said exact same part #
Could it be a solenoid?

 

I think a solenoid should throw a code. Be a bit patient, one of the tranny experts should see this thread pretty soon. It does sound mechanical to me, the absence of codes pretty much points to that.

Stupid question - fluid is full, no visible leaks? If 4wd, is the transfer case overfull?

 

You need to know how the trans works.
It is all electric operated.
The very first thing that has to happen when you put it in any gear is the Electric Pressure Control Valve has to be commanded to open, by the computer.
This allows fluid to all other parts of the system so the valve body will work and feed calibrated fluid pressure to the clutches and band through their fluid filled Servo drivers.
If you have no forward gears but have reverse, fluid is being passed by the EPC solenoid.
Reverse has no other fluid control but the shifter position because no up or down shifting ever takes place.
If no gears forward or reverse the EPC or the front pump is faulty or in trouble.
The converter may be the cause if not installed all the way in place.
If the converter is not in place, running the motor can wreck the front pump.
Until this is sorted out by some one who understand the system, you don't know what situation you have.
Making swaps and not paying attention to detail is often not just a bolt up and go.
I wish you the best of luck on this.

 

If it worked for about 400 miles in one day, then started to kind of "float" before catching, then went out after half of the second day, could it still be computer or torque? I am hearing a lot of people say clutch packs??
And Reverse works PERFECTLY

 

If there are no codes indicating any electrical fault then the internal mechanics of the transmission would be suspect.
The computer has no way to monitor mechanical faults, otherwise.
Good luck..

 

I am banking on clutch packs.
I just hope nothing from the swap is causing the trans to go out...

 

FWIW......I had a problem with my tranny floating a few of times before engaging. I had changed the filter/fluid maybe 2K previous. Turns out the trans filter I got from Autozone in the kit had partially slipped out of the intake tube. There is no bolt to hold the the filter in place...just the tube friction. I noticed it a couple of times on an incline...possibly when the fluid was toward the back of the pan and the tube was sucking more air than fluid causing the tranny to "float" before catching.

I was on a road trip back in my hometown when it happen and watched the tranny mech drop the pan and seen the filter partially laying in the pan when he lowered it slowly down. The trans shop is very reliable...been there for decades. They said the filters in those Autozone kits are made in China and the diameter tolerances on the rubber bushing often do not keep the filter in place. They recommended filters built in the US. Can't remember the name at the moment but that new US made filter fixed the problem.