Shifting problem

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Here's the haps...

Highway speeds. (Any speed really. Just most noticeable on the highway.)

Climbing a hill.

Goes slower and slower and slower. Nothing changes as far ar RPMs, or shifting. Just goes slower and slower.

Until I reach the point of frustration, and put my foot into it, to make it downshift.

Then... I am climbing on the tail of the vehicle in front of me.


There has to be a compromise where I simply keep up with traffic...


Checked the FIPL this morning. Surprisingly, it is adjusted correctly.


What else could be the problem?
 

ifrythings

Full Access Member
Joined
Dec 17, 2011
Posts
734
Reaction score
485
Location
BC
Almost sounds like your torque converter clutch is slipping but that doesn’t completely explain it happening at all speeds.
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Brand new TC.

And they were very proud of that "full lockup" ! lol
 

Black dawg

Registered User
Joined
Jan 9, 2006
Posts
3,995
Reaction score
703
Location
sw mt
probably upshifts pretty quickly to? I would give it a little more tps and see how you like it.

what is it set at now? at what Idle speed?

when you check the tps, run the throttle slowly to wide open and make sure voltage follows like it should
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Actually, it SEEMS like it takes a long time and winds out, before it shifts. It just feels and sounds like the trans is being worked harder than it should in the lower gears.

How do you give it more TPS??? Either it's got it or it don't. LOL Do you mean make the voltage higher?

I checked the FIPL correctly. The voltage was at 1.2 at idle. And 3.8 at WOT. The transition was smooth. :D
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Trying to get back to the really pertinent question...

When in highway traffic... When going uphill... Doing the normal stuff trying to keep up with traffic. You know, kind of pushing the pedal a little more, that sort of stuff. The stuff that normally keeps you moving with the flow....

Yet you go slower and slower and slower... Until you get so far behind the vehicle ahead, people behind you are getting pissed at how slow you are going.

So, you really step on the gas to get it to downshift.... And now before you know it, you are climbing up the tailpipe of the vehicle in front of you.

What else besides the FIPL could be causing this?

Even my OLD truck with just a C6 would at least keep up with highway traffic on hills without having to stomp on the go pedal.
 

Black dawg

Registered User
Joined
Jan 9, 2006
Posts
3,995
Reaction score
703
Location
sw mt
On my truck, the tps was usually set to about 1.35

It really depends on where the idle screw is at though. I would adjust the voltage up in increments....it doesn't take much......see if you like it better
 

dgr

Full Access Member
Joined
Aug 5, 2012
Posts
915
Reaction score
238
Location
sac town
I think that he's saying he doesn't want to downshift. Just go faster with more pedal. Turbo is the proper answer. Then intercooler and bigger pump.

Might advance the pump timing a bit. Mine was a dog with the pump retarded. It's pretty rattly when cold now but has more pep. I should dig out my ferret and see what it's at.
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Thank you. I hadn't even considered that it might be a fuel delivery problem.

All the more encouragement to get the dual feed fuel system done.
 

snicklas

6.0 and Loving It!!
Staff member
Joined
Aug 7, 2006
Posts
6,164
Reaction score
2,342
Location
Greenfield, Indiana
Another thought, that you mentioned in your troubleshooting....

Maybe it has to do with the falling apart throttle cable..... if you are pushing just a little, and all you are doing is streching the cable, and not actually moving the throttle lever until you really move the pedal.

What made me thing of it was, I've noticed on my 11 F-150 that's a "fly by wire" throttle, depending on how I have my foot placed on the pedal effects how the throttle responds. If I have my foot toward the bottom of the pedal, it takes more movement of my foot, than if I am pressing more toward the top of the pedal. The geometry is different in the movement, and the actual pedal has to move on it's pivot before the arm actually moves. If it's at the top, the pedal itself doesn't move as much before the throttle responds. If you have something similar because of overcoming a manual "catch" (you mentioned the FIPL/TPS voltage was smooth except when the throttle "popped" because of the failing plastic). If the cable is stuck, any "slop" will move before the actual throttle lever moves.......
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Another great suggestion!
 

chillman88

Supporting Member
Supporting Member
Joined
Feb 22, 2017
Posts
6,022
Reaction score
6,152
Location
Central NY
You are kind of noticing the reason so many of us have a manual transmission lol. It is somewhat tunable though. I have my C6 truck set up high and tight. No electronics involved though....

Yep. Diego is a good truck, but I miss the manual transmission in Tank. This road salt needs to go away and take the cold with it!
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
An update:

It's not the throttle cable.

I removed the RABS control module. The electronic part, behind the glove box.

Shifts are smoother. Problem is no longer there, most of the time.

There is still one big hill, on the way home where I am either constantly losing speed, with normal pedal operation... Or gaining speed, because I had to put my foot in it.


As I said, I'll replace the throttle cable when I have the chance.

I'm going to replace the FIPL, even though it is reading correctly.

And I am going to replace the speed sensor on the rear diff, when I have the chance.

May even replace the tach sensor on the front of the engine just for kicks and grins.

But yeah. Truck is at least a bit more driveable now.
 
Top