[Zondac12]

Hi all, just joined to hopefully pick someone's brain. Upstate NYer (near the Mass/VT border) with a '97 F250 ECLB. I'm aware after hours of reading that there's a resident E4OD expert, hopefully he will see this.

To make a long story short, the truck has some miles...332K as of now! I bought it 6 years and 9k ago with 2nd gear barely working. I've limped it along using manual 2nd, driving with a light foot and have gotten a lot of work done frankly. It's not a toy , daily driver is an '87 Grand Marquis and the toys are hopped-up 87/88 Cougars. Finally getting around to really troubleshooting because I've never felt like I should give up on it.


Where I am now after a bunch of Sonnax parts and some other drive-testing: I rigged up a string tied to the solenoid harness plug (don't ask me why it took me 6 years to dream this up...). I took off in manual 1st, hammered down and pulled the string. I'm aware that this condition gives me 4th and 2nd, and I found that Manual 1 and Manual 2 keep you in 2nd, moving to (D) gives you 4th. I was shocked with a solid banging 2nd shift, the likes of which this truck has never been capable of, even with the EPC wire disconnected. (Note: I have installed all 3 Sonnax 1-2 fixes just recently and a TransGo HD-2 toward this effort)

So my question is, why did this happen? I haven't been able to find a recounting of a test like this, nor a description of what's going on hydrualically with no solenoid pack power. If the band is still doing the work here then clearly the clutch is indeed done for. But if only the clutch is active...then perhaps I have an SS1 or SS2/wiring/ECM driver issue?

Cheers,
Paul

 

[Mark Kovalsky]

With no power to the solenoids you always have maximum EPC (and therefore line) pressure. You also will only have second gear in 1 and 2, and fourth gear in D. The intermediate band will be applied anytime the shift lever is in 2, with or without solenoid power.

 

[Zondac12]

Hi Mark - got it, this jives with what you've said in the past. So in my test, I kept the truck in Manual 1 on the lever while causing the electrical circuit "break". The intermediate band *should* not have applied, assuming everything is in factory order?

 

[Mark Kovalsky]

The intermediate band should only be on with the shift handle in the 2 position, not the 1 position. There could be some cross leakage in the valve body or center support.

 

[Steve83]

This diagram includes the Ford charts for what the solenoids do, and the caption has more info:

 

[Mark Kovalsky]

Here is a chart that shows what friction element is applied in each condition:

 

[Zondac12]

I have seen those diagrams, though the Supermotors one had a bit about the solenoids that I had forgotten (and had backwards in my head as it turns out). I had speculated on how 2nd gear is possible with no solenoid pack power but I was wrong. Clearly there must be a redundant "bypass" circuit since the solenoids require energizing to allow fluid flow, not the opposite. It's seeming to me that whatever this fluid path is, allowed 2nd to apply firmly but more important, "instantly" in my test.


Since I've already comitted sacrilege by breaking a wire within the harness...why not mess around a little more? I'd like to isolate out the PCM and wiring by sending ground to the SS2 pin, redundantly, during the 1-2 shift. I think I'll simply pierce the 315(P/O) wire and attach an alligator lead/Scotch-Lok and wire up a temporary switch in the cabin again, in this case sending it a second battery (-) connection.
Any reason why this would be a bad idea?

 

[Zondac12]

I don't *think* I've seen this posted here before in my search...but it's on Pirate4x4. Been studying it trying to understand. The legend helps but there are certain conventions I wish I knew about the passages on the sides of the valve bores as shown. But it does look to me like applying the Int clutch only has two potential sources of pressure, and it looks like there doesn't exist a circuit that bypasses the 1-2 shift valve and Int accumulator. Which I would say validates the results of my "sudden power loss" check.
It also looks like the band depends on the 1-2, 2-3 and maybe even the Timing Valve.


Dubya-dubya-dubya DOT atraonline DOT com/]ATRA - Automatic Transmission Rebuilders Association gears/ 2005 /2005-01/ 2005_01_006.pdf (I can't post links - google "Check those checkballs")
This also gave me much more insight the second time around, looking at the chart while reading it! And according to that, this diagram...might be a newer year since it doesn't show all of the CB's he talks about.

I went ahead and did that test, no observable change. I can't see there being a lack in + current since in the higher gears, either SS1 or SS2 is operating, along with TCC and CCS (if I'm in 3rd anyway). And if I'm not mistaken I feel the TCC come on still just above 30 mph even if I hold Manual 2nd and keep it floored. I see that EPC has it's own power source but everything else runs off the red wire and it's not exactly a thick gauge. But the PCM is clearly grounding where and when it should.


Based on everything so far (and one remark Mr Madden makes about SS2) I have to suspect the solenoid pack. I ordered Sonnax's one from RockAuto. I did see a snippet of a TSB that reccomended replacing the pack if the vehicle has over 100k miles. I'm 3x that so frankly I dont mind considering it a $140 PM. I'll post back if it solves my problem. If not I'll continue doing what I've done the last 6 years until I truly become sick of helping it do its job