[CNY_Dave]

Unless I really need to take off the exhaust and driveshaft for some other reason, I'm not pulling the trans apart, I don't have the time to devote to it.

But, if the spool valve is in the valve body, the other necessary changes probably are as well. If they changed the plumbing to the transfer solenoid, that could be a difference in the body of the trans, though.

Besides, the thought of trying to get the trans pan off in one piece after using the ultra-gray doesn't thrill me.

 

[plain OM]

I obviously misunderstood when/how the change to the later version of the 4EAT was implemented.

It now appears that there were (at least) two changes related to the AWD control.

The earlier change would have been the relationship between the throttle position, duty cycle, and clutch pressure, which is the topic of discussion here. This seems to have been introduced into the 4EAT Phase II for MY2004, and could be the change noted in the referenced TSB (see below, tnx Peaty). But the solenoid/transfer valve remained in the original location in the extension case.

Subsequently, the location of the AWD solenoid was apparently moved from the extension case to the valve body, at least that's according to Subaru documentation. This occurred at the same time the use of "accumulators" was eliminated. The accumulators were used to smooth shifting; the newer system makes use of more precise control of the shift solenoids. Subaru refers to the newer approach as "direct control". This might have been coincident with MY2005 Outback/Legacy production, and would have been reflected in the different valve body and tail section exterior.

I had previously thought the two changes were at the same time.

Nevertheless, it's interesting that according to my 03 FSM, the MPT 4EAT had the inverse relationship, that is, the higher the throttle, the lower the duty cycle, and the higher the pressure. (See below). However, in 03, the VTD 4EAT already had the proportional relationship, that is, the higher the throttle, the higher the duty cycle and the higher the pressure, which is what ntippet clearly has on the 2004 MPT 4EAT.

In regard to swapping the valve bodies, I don't think this will work because I believe the AWD solenoid/transfer valve might still be the tail section area.

 

[CNY_Dave]

My '04 trans definitely has the transfer solenoid in the tail housing, just like my '03.

 

[ntippet]

I was referring to the small valve assembly that accompanies the transfer solenoid, not the entire transmission valve body.

 

[plain OM]

I was referring to the small valve assembly that accompanies the transfer solenoid, not the entire transmission valve body.

My misunderstanding. You're right. Take the AWD solenoid/valve from the tail section of old tranny and put it in the new tranny. That way, if the rest of the piping is the same, the valving will respond to the old (2003) TCU's duty cycle signal (inverse throttle/duty cycle), and it should work properly. But that does mean taking down the tail section, which there's some reluctance to do at this time.

Okay, back on track.

 

[ntippet]

At least taking off the extension housing isn't too hard, the only components in the way are the exhaust and driveshaft.
Tranny does not have to go anywhere, although it sounds like CNY might leave that project for another day.

 

[CNY_Dave]

"Only". Heh. have you lifted the front exhaust section on an H6?

Actually it wasn't too bad after I strung a sling (tie-down) across the front of the exhaust and the rear and used that to hold it up, I was able to lift and pull the strap without too much effort.

Just removing the tailhousing wouldn't be so bad, I just don't want to do it for awhile.

 

[ntippet]

Yes and Yes.
Typically will drop the entire exhaust in 1 piece, from the headers to the muffler.
Never have to bother any of the flanges this way.

 

[Glennda5id]

You guys are crazy, I just found this thread on this topic. That being said, this is all very interesting.

Anyways, regarding the revised transfer clutch solenoid. The '04 Part, 31942AA130, is marked as the superseded part for the 03 transmission. So this is not where the changes are occurring.

http://opposedforces.com/parts/lega...ion/at_transfer_and_extension/illustration_3/

Also, regarding the VDC or not VDC. The trans id of the transmission that Dave has is definitly an '04 Non VDC. Unless they swapped the sticker, it is not VDC. I believe the VDC trans start with TVXXXXX vs TZXXXXXX

 

[CNY_Dave]

You guys are crazy, I just found this thread on this topic. That being said, this is all very interesting.

Anyways, regarding the revised transfer clutch solenoid. The '04 Part, 31942AA130, is marked as the superseded part for the 03 transmission. So this is not where the changes are occurring.

http://opposedforces.com/parts/lega...ion/at_transfer_and_extension/illustration_3/

Also, regarding the VDC or not VDC. The trans id of the transmission that Dave has is definitly an '04 Non VDC. Unless they swapped the sticker, it is not VDC. I believe the VDC trans start with TVXXXXX vs TZXXXXXX

I'm trying not to get any crazier on this than necessary, I have a trans that works with a clutch-pack and transfer solenoid that work, I don't want to play junkyard roulette again, to get the proper trans only to find out it doesn't work right in some other way.

A buddy even found a MOS inverter chip that will work 0-18V, all I need to do is run it through a pair of power transistors to drive the solenoid (that's assuming there isn't just a 2-transistor inverting solution out there using just 2 power transistors). I haven't really looked yet.

 

[cardoc]

"Only". Heh. have you lifted the front exhaust section on an H6?

Actually it wasn't too bad after I strung a sling (tie-down) across the front of the exhaust and the rear and used that to hold it up, I was able to lift and pull the strap without too much effort.

Just removing the tailhousing wouldn't be so bad, I just don't want to do it for awhile.

I do believe Dave is tired of lifting heavy parts while laying on the ground.

Maybe you should invest in a lift.

 

[CNY_Dave]

Heh, I broke my wallet spending $100 and change on the trans jack... $168 at horrid freight, on sale for 130, 20%-off coupon.

I would live to snag a lift, even one of those that just hoist by the wheels.

What especially sucks is even with the occasional raise, some which didn't suck, figuring in cost-of-living, fuel and heating oil (not in the cost-of-living index) and raised taxes, I am making less now than when I moved to the area 7 years ago.

A lift was on my list, I have a 9 or 10 foot ceiling so it was a natural thought. By now I was not supposed to be still grubbing around on the floor...

 

[CNY_Dave]

I'm going to attempt this on the output side first, I found an inverting driver that will take the output of the TCU and drive the solenoid directly.

http://ww1.microchip.com/downloads/en/DeviceDoc/25006a.pdf

And ohcrap, just realized while I was ordering stuff from Digikey I forgot a power resistor to terminate the TCU output...