Anyone ever checked TC_Slip using Torque Ap in a Windstar

Has anyone ever used the Torque Ap to monitor torque converter slip (TC_Slip)? (or AE or Snap On)

Been battling a P0741 code with flashing overdrive light (torque converter not locking when commanded to), so far have swapped the oil pump drive shaft for the Sonnax one with fresh seals, and swapped the valve body+solenoids out (8 out of 14 reasons why the torque converter might not lock up lie there).

Just tried Lubegard Red and it seems like the TC Slip RPMs are reduced (went from mid hundreds to low hundreds) but have not had it to highway speeds yet. The Ford diesel truck folks note TC slip values in the low tens (< 40), but their converters have multiple clutch discs I think. Need to know what might be typical for a properly functioning Windstar, particularly a 1998, 1999, 2000 one.

I've never used the type of SCAN tool that could monitor torque slip. Of course the PCM has the ability to calculate it from the engine RPM and the TSS.

This may be obvious, but I think the torque converter clutch has only a two things that can cause it to slip: (1) bad clutch (2) low pressure on the clutch piston. If the cause is (2) then there are several possible causes: (1) pump pressure is low (2) a bad TCC PCM (3) a leak in the hydraulic supply line. I can remember reading how the TCC works and found it to be a bit more complex than a simple control valve supplying hydraulic pressure to the clutch, and that the system has a fairly complex way of controlling the differential pressure on the clutch hydraulic piston.

FYI, my experience on the AX0D/AX4S has been that wear of the internal clutch friction disks has been minimal (e.g. <0.005"), even after 100,000 mi of transmission use, but other surfaces, especially transmission bushings have much more significant wear.

Tom, appreciate the insight. I was wrong above, there are 18 things that need to be correct for the converter to lock up, see:

http://www.atraonline.com/gears/2007/2007-11/2007_11_4.pdf

Since I know this 150 K mile Ford authorized reman has the correct sprockets, etc., the fixes I've applied so far (the reman valve body includes a new pump and solenoids) it looks like 14 out of 18 possibilities should be covered.

Just so the casual Torque user for Ford is aware, the calculation provided in the software's torque converter slip calculation isn't correct, see Tugley's post on ford-trucks.com:

http://www.ford-trucks.com/forums/1322163-updated-torque-pids-3.html#post14593947




Torque Converter Slip
Short Name: Slip
PID: 2211b8
Units: RPM
Max/Min: Max 1000.0/0.0 **
Equation: ((A*256)+B)/4
ver on Ford-trucks.com
I haven't applied this fix, the numbers I get are like 3x too high.

Did you check pressure levels in the transmission levels before & after pump/valve body replacement? Did you see a change? Even if you didn't measure pressure before, have you checked is since and is it in spec? Is the clutch engaging at all (e.g. do you see engine RPM's drop when the clutch tries to engage?)

There are a few causes associated with seals internal to the unit:
9. Turbine Shaft Seals Damaged or Missing (not sure all these can be accessed w/o removing the transmission)
14. Damaged or Worn Stator Support
15. Worn Torque Converter Hub Bushing
16. Torque Converter Clutch Worn or Damaged

Also the TCC PCM solenoid signal can be monitored, to verify the PCM is sending the right electrical signal to the transmission. It should "pulse" during the application of the clutch, then go steady 12(?) volts to lock the clutch.

Did you check pressure levels in the transmission levels before & after pump/valve body replacement? Did you see a change? Even if you didn't measure pressure before, have you checked is since and is it in spec? Is the clutch engaging at all (e.g. do you see engine RPM's drop when the clutch tries to engage?)

So far my diagnostics/history looks like this:
1.) At 160 K had to swap the engine for a 2003 30 K mile (Carfax verified) used engine (leaking lower intake gasket led to hydrolock). During the swap I r&r'ed the input shaft converter seal somewhat inexpertly, it was hard to remove and at one or two points may have pried against the bushing or whatever that is beneath the seal (see below). Did not replace the converter and without a fresh sealing surface the seal weeps a bit but no active leak. Did change out 10 quarts tranny fluid for some full synthetic Valvoline Mercon V I had squirreled away. Trans operated fine.

2.) November at 182 K or so got the flashing OD light, R&Red the range selector and light went away, but then again it was a cold winter.

3). March/April flashing OD light comes back, took to trans place, scanned for codes before and during drive, P0741, shop owner said all engine conditions were right to call for lock up, ECM calling for lock up and not getting it.

I can feel/sense when the converter locks in as rpms drop about 300 or so.

4.) Decided to install reman valve body per above, included new Ford pressure control solenoid and known good TCC and other solenoids,rebuilt oil pump, plus sonnax oil pump shaft and new Ford seals. Dropped pan for first time since engine swap, magnet pretty clean no metal shavings seen, changed fluid for fresh semi synthetic Ford Mercon V. I had one hard code that was TCC related (picked up on standard OBD2 reader, can't recall if it was sensor or solenoid related)), cleared and did not come back. Have NOT checked pressures, doesn't look like Autozone has one in their loaner tools. and I am not sure where the tap is on an AX4S.

5.) Converter will lock in 3rd at 37-40 mph. Will not hold lock on highway in 4th (blinking light) Drove the backroads to work for a couple weeks this way with no light.

6.) Added Lubeguard red, "drove in" for about 30 miles so far on back roads in third. Still will not hold lock in fourth on highway, iffy at 45 on secondary roads in fourth. The Lubegard folks said in can take up to 150 miles to take full affect.

There are a few causes associated with seals internal to the unit:
9. Turbine Shaft Seals Damaged or Missing (not sure all these can be accessed w/o removing the transmission)


One of these turbine seals is accessible on the larger of the two splined shafts that extends into the converter (w/converter removed). I did not change during engine r&r. My impression is to get to the other one or two on this turbine shaft the valve body, chain cover, sprockets/chain all need to come out. There are springs below the chain cover that need to be replaced just right for this reason, can't be done with trans in the car .


14. Damaged or Worn Stator Support
think this is the "largest diameter+shortest" of the shafts extending into the converter. I do not recall any damage and did not damage it during input shaft seal r&r


15. Worn Torque Converter Hub Bushing
not sure what this is, possibly below the input shaft seal. Or is it inside the converter? See comments above.


16. Torque Converter Clutch Worn or Damaged
Beginning to consider converter R&R because I need the van to haul around a bunch of body parts for a car I want to restore this summer,


Also the TCC PCM solenoid signal can be monitored, to verify the PCM is sending the right electrical signal to the transmission. It should "pulse" during the application of the clutch, then go steady 12(?) volts to lock the clutch.


Can I do this with hat pins and a DVOM, would think a Snap On scanner would be required. Or maybe the Equus 3160 ?

Not sure how to proceed, if the van didn't have some rust issues I would consider replacing the trans as I've found a couple options less than 1 K. Engine only has 57 K on it. New Ford back axle. Fresh brakes/rotors/caliper brackets. Just rebuilt the alternator w/new regulator was supplying far to high a voltage).

Tom, I appreciate any advice you or others might provide.

The stator is part of the torque converter. There are three parts, impeller, turbine, and stator. The stator sits between the other two. It responsible for making the torque vs delta-RPM curve more abrupt (e.g. low torque at low RPM, but extremely high torque above stall speed). The stator support is screwed to the transmission, and protrudes into the torque converter. Google "AX4S stator support" and you'll see images that hopefully will help jog your memory. I think the "converter hub bushing" may be inside the converter as well based on a comment in Transtar's product manual for the AX0DE/AX4S/AX4N FM71 torque converters.

I monitored the voltage at my TCC solenoid using a standalone oscilloscope. Put a straight pin through the wire and clipped the scope probe to the pin. I road tested it, by getting another person to drive, but you probably can do the same thing with the vehicle on jack stands.

Thanks Tom. Will investigate a little further per above, but need to decide whether to replace the trans, or try replacing the converter alone.

A call to Sonnax indicated that their stator support ($75 on rockauto) needs to be fitting by taking the whole valve body/chain cover/chain apart.

Trying to find out if the turbine shaft (input shaft?) can be r&r'ed from the converter side.

If I could do both plus the converter it would seem every base has been covered.

I agree that replacement of the stator support requires removal of the transmission guts (e.g. valve body/pump/chain cover/chain, etc. down to the housing)

http://www.shinseiauto.com/japanese/transtar/usfordax4s04.pdf

The turbine shaft (673) is shown on the second page of the PDF file (pg 249). Notice that it goes inside the drive sprocket which drives the chain. There's a c-clip that retains the turbine shaft on the drive sprocket, so I don't think you can reasonably remove the turbine shaft through the stator support (even if the shaft could move through the support in that direction).

Unfortunately you'll need to break it down and much of this assembly was never intended to be performed with the unit in the vehicle, so you'll be severely challenged by leaving it in the vehicle.