95 f150 SC 4x4, 5.8l, E4OD, 3.55 8.8 rear.

Previously on E4OD Shifting Characteristics...😁

if you remember, I had 2 aftermarket VS Sensors bad outta-the-box. My Speedo was jumping at freeway speeds and the aftermarket units would not even register. ABS light on, no Speedo and tranny kinda freaked out with no VSS reading.
Re-installed old unit, and the trans was shifting very hard...but did not throw a code. Reset the 'puter and trans went back to shifting perfect...(and now that i am thinking about it, i wonder if i reset the 'puter before reading the codes....hmmm) then got a Motorcraft VSS which seemed to fix my Speedo issue. All was good.

Well........today took the truck to the Marina, about a 20 min drive half on freeway. Cruised along at 70 mph. Very happy. Untill i got off the freeway, the hard shifting returned...when I stopped, I checked and got Code 628...which is torque convertor slip.

I disconnected the battery and went about my business. A few hours later I rechecked and code cleared...drove home but took back roads. Seemed to shift perfect again, until just before I got home...hard shifting returned, as did code 628.

Looks like a TC may be in the future but before by go there, this trouble seemed to start eith the VSS thing...is it possible that a VSS or even a tone ring issue is casuing the code and shifting issue? It seems odd things were perfect till i screwed with the VSS.

The trans seems to shift perfect until this so I'm hoping it's an anomoly rather than a TC going bad, or worse, a tranny needing overhaul.
I am reading about The solenoid pack but I'm not sure where it is or what to check...
thoughts? Suggestions?

Dan

 

It's not the solenoid pack, so don't open the trans to get to it.

The slip code is set when the PCM measures that the engine RPM is higher than it should be. It only looks at this in fourth gear with the torque converter locked. It could be a bad torque converter or a bad VSS. Usually it's the torque converter.

There is a way to see if the torque converter was really slipping. Open the cover on the front of the trans. Look in the bellhousing at the front of the converter. If it has been slipping the front of the converter will show some bluing, not unlike what you'd see on a pistol.

 

Good suggestion! I'll look at that...what color would be expected?
if I'm really lucky and it's not the TC, what would be the next likely cause?

Dan

 

Isn't bluing always blue?

Otherwise, it would be called redding, or greening, or oranging, or purpling, or....

 

...that was helpful...
what I was asking is what color is a TC normally? But thanks for calling me stupid....

 

You're welcome!

The torque converter is unpainted steel from the factory. If it has been replaced over the years many aftermarket places paint them various colors.

 

There are several bluing techniques that offer different appearances. . I would imagine this is what he is talking about. More of a burnt look for lack of a better term.

Here is an article that may give you more insight as to what has been added regarding your issue. Sandy

https://www.fullsizebronco.com/threads/code-628.177150/

 

I haven't had a chance to pull the cover yet, but I cleared the code and did some driving around town with the OD off...drove perfect. If it is a TC problem, am I hurting anything by driving it?

for the record, I understand what "bluing" looks like.

 

The convert slip code is more often than not, electrical related as opposed to mechanical failure. It's possible you're having PSOM issues, rather than VSS issues and if it's bad,it will set the slip code but there's a lot of things than can set that converter slip code too. That's the one that almost goes in hand in with other issues.

 

I've been driving the truck wit OD off with no issues. TC engages and disengaged as expected, shifting is perfect. Before taking it in for a shop to diagnose, I figured I better check the fluid level. I had checked the fluid for color and smell, but with the engine off. It's a PITA to get to the dipstick with a hot, running engine.

anyway, checked fluid properly, warmed up and engine running, and it was 2 qts low. I topped it off and took it for a freeway drive using OD. I can't get it to replicate the harsh shifting or the code. Even the high speed vibration is gone....so for the knowledagble e4od guys, how sensative are these things to low (only 2 qts low) fluid level? Could that have caused the TCC to chatter or slip at high speeds, Causing the code and harsh shift?

Dan

 

Possibly. That's pretty low. You'll know after running it for a couple days if that's all it is.

 

I'd also check for leaks, 2 quarts low, should see spots/puddle in driveway

 

Only two quarts low? That's a lot low. It is enough to cause the pump to occasionally suck air, which will cause line pressure to drop. The valve body will take action when it can't maintain line pressure. The only action it can take is to cut the supply of oil to the torque converter, which will cause the converter clutch to slip. I think you've found the cause of your issue.

 

Good learning experience. I've only had the truck for about 500 miles...threw the harsh shift issue 3 times. Hopefully nothing is hurt. I should have properly checked the fluid first thing...
thanks for the responses!

 

Yeah no leaks. Onky a very small oil leak, like 2 drops a day. All the fluids are clean and topped off, so I'm wondering if it was services before I got it, and they just didn't check the trans level properly after refilling? Idunno but I'll keep a close eye on it.