Tranny Shift?

[RGL38]

I have a well taken care of 2000 F-250 7.3 Xtra cab with the higher ratio rear end. It has a little over a hundred thousand miles on it. I have a trip scheduled for the end of this week to CO. Now for the big question; It has been shifting hard at about 40 miles per hour. I had the reccomended best tranny guy in our area go through the tranny and he replaced all criticale parts including the torque converter with heavy duty parts. He said the trany was verry clean and the clutches were not burned a bit. He did replace the speed sensor in the differental. I still have the hard shift. By saying a hard shift, it seems that it kicks the RPM down too much. Before I had the tranny overhauled while towing and pulling on to the interstate with a up hill ramp, a couple times it seemed like I was hit in the rear when it shifted at about 40MPH. I use Mobile 1 in it. I can tolerate the shifting, however I would like to know if there is any thing I should do before I take this trip. All help is appreciated.

I just took it out and drove it again and it shifted rough at 40 MPH and if I pushed it hard it shifted smooth through 40MPH. When not pushing it hard the RPM dropped from about 2000 to about 1200. It shifted hard with the overdrive on or off.

 

[uloadit]

what gear is it shifting in to,is it going from 2 to 3 or is it going into torque converter lockup

 

[RGL38]

I don't know. It happens when pulling out from a stop and really not gunning it and when pulling hard also.

 

[uloadit]

let me know what gear it is shifting in to ( 1 to 2 ) (2 to 3 ) ( 3 to 4 ) or lock up is at 43 to 50 )

 

[RGL38]

If the torque converter locks up above 40 then it must be the shift from 3rd to 4th as it has shifted hard below 40. I just pulled the speed sensor and it is clean.
Could the torque converter be locking early?

 

[DaveBen]

A bad speed sensor will cause the speedo to jump around or not read all the way down to Zero MPH.

Dave

 

[JRJ04]

that sounds pretty normal to me...mine jerks me pretty good when it shifts to 40 because thats around the speed when it goes into lockup. Did they guy put any heavier duty parts in the transmission? If he did...that should be pretty normal. Do you have a chip in it or anything like that?

 

[uloadit]

he could have put in an on/ off lock up valve, and did away with the P.W.M.lock lock up.(Pulse width modulation)

 

[RGL38]

No chip. He put all heavy duty parts in it. I now have about 130 miles on it and I have to say it is better. If I ease off at about 35 but still accellerating it shifts soft. If I am going like trying to catch traffif on the super slab it is soft. It is just that inbetween thing accererating somewhat quickly and the jerk that worried me.The big test is when I am hooked to the trailer and pulling onto the super slab here. It is a up hill pull to get up to speed.

 

[WD40]

I would drive by the tranny guys shop and let him drive it.
Doug