Hello folks,

I was test driving the 56 today and started to experience an issue with the 1-2 shift. Right when you expect the trans to shift into 2nd, it feels like it hits neutral instead. Revs climb, I back out of the throttle and after a second or two it jerks into second and then everything seems ok from there. Until the next time I stop. This started gradually and became worse, to where it was going it every single time I stopped at a stop sign.

I tried putting the shift lever in 2nd gear, and then the 1-2 shift seemed ok, strangely. Could be an anomaly though.

The transmission is a new rebuild from TCI with maybe 20 miles on it. Torque converter is new. Filter is new. Trans cooler is new. Using a PCS transmission controller which has not thrown any error codes.

Oddly, when I first drove the truck while bedding in the brake pads it did not exhibit this behavior. It started the second time I took of for a spin and was worse today.

I've been researching the issue online, and it 'seems' like maybe it's common and could be related to the 1-2 accumulator (AODE/4R70W Erratic/Prolonged 1-2 Shift). That appears to be related to wear, and this is supposedly a rebuilt transmission. But who knows if they checked the 1-2 accumulator.

Before I pull the pan and then the accumulator to check it's condition, I thought I might ask here to see if anyone has any opinions or experience a similar issue?

Thanks - Gustave

 

Sounds like shift linkage. My 01 F250 (4R100) did that, the column shifter bracket on the steering column was loose, tightened it up, no more problem...until about 5 years later. I can't get the bracket any tighter, so I have to make sure that it is actually shifted fully into gear.

 

Thank you.

Yes, the linkage is the first thing I checked. I wanted to ensure that when the shifter was in "Drive" that the transmission selector arm was also in "Drive". I did adjust the cable length just a tad. But that does not seem to have been the heart of the problem.

Gustave

 

In my case it was not the cable adjustment, but the shifter itself not setting fully in the detent position.

 

Based on my limited knowledge of transmissions, the first place I would look is for contamination in the fluid. My trans builder gives me an inline filter with every trans he builds for me...he says if I don't use it for the first week then don't come back cryin' about shift issues. Crap in the fluid can come from within the trans, the convertor, the cooler, or the cooling lines themselves. Sometimes new fluid will dislodge something that laid in a line for years and it now becomes a problem.

 

Have you gotten a chance to play with the controller yet? What is it saying when the 1-2 shuffle happens? Manual 1-2 shift? Line pressure? I'd be tempted to find which solenoids are open/closed for 2nd gear and check the voltage

 

I think I would first try to determine if it was an electronic error or hard part issue. I don't know much about your controller you have, but I think they all have a TPS connection of some sort and probably require calibration. The TPS is like the TV cable on a non electric transmission and would play a role in controlling transmission pressures. If that is out of adjustment I would think it could cause a host of issues. I'd double check all that stuff.

 

Thanks guys for the input.

Recall that every single part of the system is brand new. New trans, converter, cooler, cooler lines and ATF. With a new B&M extra capacity pan.

I've got less than 20 miles on it.

The controller is generic, but specifically programmed for an AODE by the manufacturer. All of the adjustment ***** are set for the baseline recommended by the manufacturer. The controller has about 90 different possible error codes, but I am not seeing any of them. If it were a wiring problem the controller would probably catch it.

Notwithstanding the forgoing, something is wrong with either the trans, the controller or the wiring.

I am fairly sure I have the fluid level correct. I've added 4 gallons at this point (16 quarts). The trans and converter hole about 12 quarts from what I've read. The large pan adds an extra 3-4 quarts and there is the cooler and AN-8 lines which are fairly long, leading to the back fender.

I'm going to start by dropping the pan and checking what I can, including the 1-2 accumulator, which seems to be a common culprit. I'll call TCI and PCS to ask them for opinions, but this is a bad time of year to be calling companies as many are closed for Christmas break.

Gustave

 

So you did calibrate the tps voltage? Closed throttle and wide open throttle? I'm not familiar with the pcs Controller so maybe you don't even need to

 

Ah, each time the PCS is un-powered, then upon power up (i.e. reconnecting the battery), with ignition on, before startup, you have to slowly depress the throttle to full open and then release. That 'teaches' the controller the TPS limits. Does that make sense?

 

Update:

I dropped the pan to check things out.

No metal shavings found. Fluid was bright red and clear with no burnt smell at all. There was a fair amount of black 'dust' in the fluid. The TCI instructions state that this is to be expected when changing the fluid at 500 miles after break in. Not sure if it is normal after only 20 miles.

I popped out the 1-2 accumulator. The springs that came out looked very odd to me at first. The upper ones were Red (dual concentric springs) and the lower one was Black, very short and very stiff. Neither matches the available factory spring colors of Pink, Purple, Violet, White etc. After some research I have concluded that these springs are most likely part of a shift kit offered by Fairbanks TransAction. I do not know if this kit was installed by TCI or previously.

Here are some photos of the springs:





The 1-2 accumulator piston looks pretty new. It is the updated molder rubber type as opposed to the early style aluminum with O-rings type. The top side of the accumulator had what looked to be an alarming amount of debris inside it:



However, when I scraped out the stuff with a screw driver it turned out to be mostly grease of some type, maybe assembly lube or Vaseline. I am hypothesizing that this stuff, along with some debris might have compromise the function of the upper piston seal. I will replace the piston and cover and install factory springs, reload with fluid and take a test drive.

If this is not the issue then I will have to pull the transmission and decide on next steps.

 

Why can't you tell if the fluid is at the correct level? Overfilling will cause aeration, which could cause the symptoms you describe. That would be a pretty deep pan to hold an extra gallon.

Could your long lines be draining back while sitting?

 

Thanks Ross. Well, the B&M pan is pretty deep. It holds 3-4 extra quarts depending on which literature you read.



The lines run lower than the transmission. But a portion of the cooler is higher than the transmission. I don't think there is enough fluid volume to drain back that it would be an issue.

But I will admit that I find that checking the fluid level on an automatic transmission to be not so straight forward. When checking engine oil I have become well accustomed to the difference in oil level between when the engine is running vs when it has been sitting for a while.

But with an automatic transmission that difference seems to be huge. I'll check the level cold and it's way above the full mark on the dipstick. Then I check it running and the dipstick is bone dry. I am aware that the fluid level that matters is with engine running and trans in Neutral, so that is what I go by.

Gustave

 

Well, I seem to have resolved my issue. Though not as a result of any serious effort. I pulled the pan, popped out the 1-2 accumulator piston, slipped in a new one with the same springs. Sealed everything back up, poured in new fluid and voila. Perfect 1-2 shifts (so far).

I did add an inline filter ahead of the cooler.

Now I have to track down a TCC solenoid issue since my controller is giving me an error code related to that. I'll probably have to pull the pan to check that out. 16 quarts of new transmission fluid for a 10 mile drive. Ah well.

Gustave

 

You're not going to pitch the fluid, are you??