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My 1997 Ford F-150 4.6 2wd has 180,000miles on it. At around 120,000miles the transmission was replaced with a new case and rebuilt using the monster in a box ss kit installed by a very reputable shop. It's long since out of warranty but I've been noticing a few hiccups with it lately. 1-2 is firm and it always has been no concerns there. 2-3 has always been fairly light, which I've always thought could be more aggressive, currently it has started holding 2nd until you let off the throttle which concerns me, 3-4 has always felt like a factory shift but now I can clearly feel it do the same thing as 2nd, it holds 3rd until you let off the throttle, I can feel the converter lock, and then it will unlock and shift to 4th and lock up again.

So to sum it up with 2/3rds throttle or wide open I get the following shifts:
1-2 firm
2-3 soft/factory and holds 2nd until I let off the throttle
3-4 firm/normal and holds 3rd until I let off the throttle
Lock/Unlock very noticeable in 3rd and 4th

I was thinking about changing the TPS and MLPS, dropping the pan, dropping the valve body, and installing a composite or factory 2-3 bonded piston with no springs, swapping the OD servo to the larger unit without the sleve and installing the sonnex OD servo pin with o-ring. Also changing the main pressure regulator valve to the sonnex one and the boost valve as well and of course fresh mercon v and a new internal filter. All of those are fairly common upgrades and maintenance.

I'm just curious if anyone has any ideas what is causing these new drawn out shifts. This rig tows my bird occasionally so I can't afford to be letting off the throttle with a trailer on a hill. I worry about damaging it.
 

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Datalog it, and see what the tps is saying; I'd throw a set of gauges on the ports, to see what the pressure is really doing at the same time. :)

You need 200psi gauges, iirc.

There could be a problem with the tps, thinking it's higher than it is; iirc, it won't shift till you let off, thinking it's near wot...
 
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