Almost a year since I had my Transmission
replaced and still when I floor it, the truck will only do 85 MPH wide open. It would go much faster with the old transmission that was broke enough for a factory replacement. Any ideas guys?
98 F150 4.6 Auto 4X4

 

To R&R the tranny they have to remove the exhaust becasue it is in the way of the T-case and it has to be removed too. Removing the exhaust may have disloged some crud and pluged one or both of the cats. You do not mention the rpms being a lot higher so I will rule out slipping. If the T-case was at fault it would have provided some sort of a sign, like a big bang and pieces all over the place. The only other thing I can thinkl of is the O2 sensors. If they have not been changed since 98 get new ones. You need only replace the upstream ones.

Regards

Jean Marc Chartier

EDIT: spelling