Surging

[Fade 2 Black]

1999 F250 CC 4X4

Bought it used last July showing 400K. Trans has been replaced at some point, history unknown. Trans shifts and works fine, only when in OD and under part/moderate throttle it feels as though the TC is locking/unlocking, best way to describe it I guess. No codes, no leaks, fluid/filter just changed and level is good.

I have a TS 6 pos chip but it does the same thing with stock tune.

Seems as though 4th gear is going south on me. While cruising at highway speeds it doesn't do it.

[Codum]

Mine has just stared doing the same thing. It started two days ago. It is the original transmission, I did install bully dog shift kit at around 200k. It started out acting up when cruising at 40-50mph and in 3rd gear, when in a no load situation, feel like it would go into neutral or slipping? RPM's would climb to 3000 then it would finally lock up and start pulling again. Sometimes If I back of the fuel and then give it fuel again it would go into OD. Last night it started doing the same thing in overdrive, again only in a no load situation. I can accelerate up thru all gears with no issues. But when coasting it wants to either go into neutral or is just slipping. Did you get yours figured out? Is yours doing the same as mine? Anybody else got any suggestions.

[rbarr]

i have a 99 with the same issues. i had it rebuilt twice and still the torque converter just keeps locking in and out till i let off the pedal. i even got the heavy duty converter and instaled a shift kit. it seems to be getting worse the more i drive it. i am wondering if it could be the programing of the computer??? anyways any help or ideas would be great. im debating putting in a 6speed manual.

it feels to me when it shifts into or out of overdrive that it would be like bouncing your foot on the clutch if it was a manual.

[Turbostang500]

To anyone,

Is it actually going in and out of gears or is it the torque locking and unlocking?

[Codum]

I ended up getting a new transmission. It was dropping out of third. Center section failure per John Wood.

[rbarr]

not 100% sure. after rebuild it would slam into third and then spike before overdrive. i increased the line pressure and it fixed the 3rd gear issue but still spikes into overdrive and torque converter locks and unlocks multiple times when it engages in third and overdrive. it feels like every time it locks and unlocks that it drops the rpms more and more until it finds the right rpm range to finally lock. its getting aggrivating...to the point that i dont even want the truck anymore.

[Turbostang500]

I would look into a reprogram and see how that does.