4R70W - HARD shifts when driving uphill

[Twisted1]

Hey guys. Today I took a 2 hour trip which ended with steep inclines to my destination (mountain area). My trans started to shift HARD when I reached the uphill roads. So hard that I thought I had gotten rear ended. The truck kept slamming into gears while driving.. The trans was rebuilt a few years ago by a very reputable local trans shop and they changed nearly everything internally.

Billet forward and direct drum, TransGo shift kit, etc.. Cold weather and in-town driving was fine. It’s just when I had to go up steep inclines that it began to shift super hard into gears. Fluid level was correct, and my Autel MaxiCheck Pro didn’t find any codes pending or active.. I don’t know what could’ve caused this condition..

2002 F150 4.6 2wd

 

[ripcord]

Which gears? Upshifts only or downshifts, too? Any blinking or check engine lights?

 

[Twisted1]

Which gears? Upshifts only or downshifts, too? Any blinking or check engine lights?

2-3 3-4 shifts were hitting the hardest. Zero blinking lights and no codes stored or pending

 

[clinebarger]

Stock tuning ECM wise?

 

[Twisted1]

Stock tuning ECM wise?

Yes stock ECM as well

 

[dogememe]

Call me crazy but bad MAF? Are fuel trims correct?

 

[Twisted1]

Call me crazy but bad MAF? Are fuel trims correct?

I did not log the fuel trims but I will do that… I know a bad MAF can cause those issues too

 

[ripcord]

Throttle position sensor?

 

[Twisted1]

Throttle position sensor?

I’ll have to check that too. But no codes for anything as of yet

 

[totegoat]

I'd manually shift it in the hills, good idea anyway.

 

[Lubener]

Engine performance can have a big affect on the shift quality.

I can say recently solved an issue affecting my Grand Marquis with 4R70W with slip-harsh bump type shifting when warmed up, cold was fine. . No codes set. Engine would have a hestitation and fuel trims were edging up the negative side. The give away was the ECT sensor was giving the wrong coolant temperature to the computer Even though coolant temp. was normal.. All has been well after changing the sensor and my mileage has gone up between 2-3 MPG.

 

[Twisted1]

Engine performance can have a big affect on the shift quality.

I can say recently solved an issue affecting my Grand Marquis with 4R70W with slip-harsh bump type shifting when warmed up, cold was fine. . No codes set. Engine would have a hestitation and fuel trims were edging up the negative side. The give away was the ECT sensor was giving the wrong coolant temperature to the computer Even though coolant temp. was normal.. All has been well after changing the sensor and my mileage has gone up between 2-3 MPG.

Great find! How were you able to pinpoint the ECT being at fault through the fuel trim readings?I would assume it would be a post EGR issue

 

[Lubener]

Great find! How were you able to pinpoint the ECT being at fault through the fuel trim readings?I would assume it would be a post EGR issue

I looked at the actual engine temperature information on my scan tool as the computer saw it.

 

[Invisible]

Shift it manually uphill under light throttle condition, medium, and hard (not full throttle or anything like that, but under power). If it consistently shifts hard, then you might have one or more bad solenoids in your valve body, though my money would be on the torque converter solenoid.