Torque Converter Locking Issues
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,704
Likes: 2,626
From: SE Florida
First, there is no such thing as MERCON III. There is MERCON, MERCON V, and MERCON SP. That's all the MERCON fluids that have ever been produced.
The 4R100 used to use MERCON fluid. As of June, 2007, Ford stopped licensing the production of MERCON fluids. They changed the formulation of MERCON V to make it compatible with all the transmissions that used to use MERCON.
So MERCON used to be the right fluid, now it's MERCON V. MERCON won't cause your problems.
The 4R100 used to use MERCON fluid. As of June, 2007, Ford stopped licensing the production of MERCON fluids. They changed the formulation of MERCON V to make it compatible with all the transmissions that used to use MERCON.
So MERCON used to be the right fluid, now it's MERCON V. MERCON won't cause your problems.
Senior User
Joined: Dec 2007
Posts: 147
Likes: 0
From: Lebanon, Oregon
no, it does it at cruising speed 55 and above, when it gets under a load it unlocks then locks, back and forth till i let off the throttle then it stays locked up. i have been chasing this issue since december
Posting Guru
Joined: May 2007
Posts: 1,141
Likes: 0
Well guys Mark's trying to help the best he can,if he say's try something take his word for it, also awhile back there was a post about the brake light voltage being low on led bulbs that would cause this, or the bulbs burn out. Check the third light also. If i did'nt explain well enough Mark will correct.
Post Fiend
Joined: Feb 2007
Posts: 7,191
Likes: 4
From: Blairsville,Ga
A friends truck was doing about the same thing except I believe it was with O/D locked out.
He said his brother adjusted the TRS and it was better
Personally I would listen to Mark and replace it
He said his brother adjusted the TRS and it was better
Personally I would listen to Mark and replace it
Senior User
Joined: Dec 2007
Posts: 147
Likes: 0
From: Lebanon, Oregon
ok, i just baught and replaced my trans range sensor(neutral safety switch). alligned it accordingly in the neutral position and it did not change a thing. any other ideas??????
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Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,704
Likes: 2,626
From: SE Florida
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,704
Likes: 2,626
From: SE Florida
It could be a bad pedal position sensor. The best way to get to the bottom of this is have someone diagnose this with the proper data collection tool so that he can see what the computer is seeing.
