New Trannie Binding Questions (Help!)

[Trevor]

Originally Posted by sperry

Are there two speed sensors? I was under the impression that there's just the one 3 wire speed sensor from the OEM tranny that gets reused after the swap. No one else w/ a 4.44 swap has had issues with binding, or with the speedo reading incorrectly if they reuse the OEM sensor.

Finally, if there really was a problem with the conversion as you suggest, then I would expect it to be at all times, not just around corners. My symptoms are right in line w/ a worn transfer clutch.

The statement from an alleged engineer shows much confusion, but I do not think the intention was to relate to the reuse of a speed sensor. That said, I agree the remainder makes no sense.

Good to see at long last, someone resisting being misled and logic prevailing.

[oab_au]

Originally Posted by sperry

Are there two speed sensors? I was under the impression that there's just the one 3 wire speed sensor from the OEM tranny that gets reused after the swap. No one else w/ a 4.44 swap has had issues with binding, or with the speedo reading incorrectly if they reuse the OEM sensor.

Finally, if there really was a problem with the conversion as you suggest, then I would expect it to be at all times, not just around corners. My symptoms are right in line w/ a worn transfer clutch.

Yes there are two speed sensors, the front one that you replaced with the SVX one, and the one in the back of the box, that reads the transfer clutch speed. The TCU compares these two readings to detect wheel spin. If they vary by less than 20% (app) It considers this as turning, and does not apply transfer pressure. If the difference is greater that 20%, it considers this to be wheel spin and sends pressure to the clutch.

With the front sensor reading front wheel speed, at the 3.5:1 rate, and the rear sensor reading rear wheel speed at a 4.44:1 rate, the difference is about 25%, up in the wheel spin area, so the TCU applies transfer pressure.

All the lower geared connersions are affected like this, just that the 4.44 has the greatest difference in speed readings.

Harvey.

[sperry]

Originally Posted by oab_au

Yes there are two speed sensors, the front one that you replaced with the SVX one, and the one in the back of the box, that reads the transfer clutch speed. The TCU compares these two readings to detect wheel spin. If they vary by less than 20% (app) It considers this as turning, and does not apply transfer pressure. If the difference is greater that 20%, it considers this to be wheel spin and sends pressure to the clutch.

With the front sensor reading front wheel speed, at the 3.5:1 rate, and the rear sensor reading rear wheel speed at a 4.44:1 rate, the difference is about 25%, up in the wheel spin area, so the TCU applies transfer pressure.

All the lower geared connersions are affected like this, just that the 4.44 has the greatest difference in speed readings.

Harvey.

Any other 4.44 owners care to comment on this? If it's true, it means every 4.44 should be binding around corners.

Since I haven't heard others mention this, I have to assume that I damaged my transfer clutch by driving around with a 4.11 rear end briefly (even though we had the FWD fuse in for the majority of the time and were at very low speeds with it out). But if other 4.44 owners can confirm the binding, you might be on to something.

One thing to note... I have a US spec Legacy tranny. No VDC (or whatever the dynamic center diff is called) like the overseas cars, which sounds like what you're describing. Are you sure the speed sensor issue even applies to the tranny in my car? I thought the center diff in the older trannys simply relied on a viscous coupler, and that the variable aspect of the diff was simply due to input from the TPS, and not electronically reactive to wheel slip.

Anyone that knows more, please comment!

[oab_au]

Originally Posted by sperry

Any other 4.44 owners care to comment on this? If it's true, it means every 4.44 should be binding around corners.

Since I haven't heard others mention this, I have to assume that I damaged my transfer clutch by driving around with a 4.11 rear end briefly (even though we had the FWD fuse in for the majority of the time and were at very low speeds with it out). But if other 4.44 owners can confirm the binding, you might be on to something.

One thing to note... I have a US spec Legacy tranny. No VDC (or whatever the dynamic center diff is called) like the overseas cars, which sounds like what you're describing. Are you sure the speed sensor issue even applies to the tranny in my car? I thought the center diff in the older trannys simply relied on a viscous coupler, and that the variable aspect of the diff was simply due to input from the TPS, and not electronically reactive to wheel slip.

Anyone that knows more, please comment!

Yes Mate, I know what model you have, and this is for the US Transfer system.

The Binding in the clutch can be from the clutch pact being set up too tight. When you build the transfer clutch up with new plates, you have to select a pressure plate to suit to thickness of the plates, too tight and it will bind, too loose and it will delay. Yours may be set up too tight, so along with the extra transfer pressure added for the difference in rotation, so it binds noticeably.

If this is the case, yours may settle down when the plates bed in and loosen up.

Harvey.

[sperry]

Originally Posted by oab_au

Yes Mate, I know what model you have, and this is for the US Transfer system.

The Binding in the clutch can be from the clutch pact being set up too tight. When you build the transfer clutch up with new plates, you have to select a pressure plate to suit to thickness of the plates, too tight and it will bind, too loose and it will delay. Yours may be set up too tight, so along with the extra transfer pressure added for the difference in rotation, so it binds noticeably.

If this is the case, yours may settle down when the plates bed in and loosen up.

Harvey.

Okay, I think we might have a bit of a disconnect about what we're talking about here.

First, I have a 4.44 legacy transmission, with the matching 4.44 rear end on the car. There shouldn't be any weird speed differentials between front and rear diffs. The tranny and rear end came from a junk yard. They were not rebuilt (aside from installing the SVX LSD carrier in the rear-end). I doubt the transfer clutch plates need to bed in... besides I did the whole figure-8 thing, and the binding did not improve.

Second, the car briefly had a 4.11 rear end paired with the 4.44 front diff. It was driven maybe 20 miles like this *with the FWD fuse installed*. With the FWD fuse out, the car had undriveable binding at under walking speeds (like 2 mph). This is what I think oab_au is talking about, and it is not the problem I'm having.

Since I replaced the 4.11 rearend with a 4.44, the car drives fine in a straight line, but binds around tight corners. The standard binding that everyone gets with a busted Sol.C or worn transfer clutch.

I added the LSD friction modifier to my ATF, and my binding has been reduced, but not eliminated.

My questions were, "how does the additive work?", and "what's the procedure/parts necessary to rebuild the transfer clutch?"

I believe I know *why* I have binding (I drove the car w/ the wrong rearend on it, and even w/ the FWD fuse installed, it wore out my transfer clutch... i.e. the same thing that happens when someone tows the car on 2 wheels).

So, can anyone point me to a parts list and how-to for rebuilding the transfer clutch? I'd hate to take it to Subaru and try to get them to do it, since I get the feeling that telling them to treat it like a '96 Legacy 4.44 4EAT won't work, and they'll be jamming the transfer clutch for an SVX 4EAT in there!