TozoM8

So I bought my 05 with the usual hard 5th to 4th downshift. Research tells me I need a rebuild valve body. I found a new one on ebay for 1/2 price of the rebuilt. Unfortunately it is the one without the pressure sensors. Mine has two on the bottom.
http://audipages.com/tozo/tn_IMG_9224.JPG
It has two threaded ports for the sensors.
http://audipages.com/tozo/tn_IMG_9229.JPG
The new has just the spot for it.
http://audipages.com/tozo/tn_IMG_9230.JPG
I took both valve body apart and found a couple more differences so I ended up putting back my old one. The fluid was new in it so someone tried to "fix" it already. I ended up throwing that fluid out and used the fluid I use on all Audi trans rebuild Schaeffer's synthetic transmission fluid. Buttoned it up thinking I am back to square one. Driving it home I couldn't believe how nice it shifted. I've tried everything to get it to shift hard, but it is "fixed". At this point I am thinking that the accumulator (apply pressure line has a T and a piston with spring behind it to soften the apply) for K1 clutch (on in 4th, but off in 5th) was stuck and re-applying K1 when downshifts from 5th made it "kick". So for now the rebuild VB is off the priority list. Back to install the Parrot BT and the Audiovox AUX input.

bigbuzuki

Good to hear your fix, however using synthetic transmission fluid in the Aisin transmission is not recommended if I recall correctly.

TozoM8

You mean it will void my warranty

bigbuzuki

Definitely void the warranty.

Is there any advantage of the synthetic fluid you have used over the approved fluid?

TozoM8

I was joking. It has 100K miles, so no warranty. Synthetic trans fluid is the best invention after the microwave oven. I rebuild ZF transmissions and I never use the recommended lifetime mineral fluid (the one that has 3 year self life). Very few transmission requires special fluid, the Aisin is not one of them.

bigbuzuki

My 2003 is still under factory extended warranty.

I had the transmission valve body replaced recently by the dealer as it was playing up @ 80,000 miles, which is half life as per the oil change schedule. All done under warranty.

I like the idea of using the synthetic oil if it is proven to be better than the original recommended oil.

Orantes

So the fix is the fluid? I like the idea of an easy fix...

bigbuzuki

Don't get your hopes up on the fluid change to fix your shifting problems.

Search the forums as there are alot of punters who have changed the fluid and problems persisted.

The valve body solenoids wear etc and need to be replaced.

Having said that, if the tranny oil was replaced earlier than the recommended 240,000 km interval, one would assume that the valve body would last longer.

I'd like to know if using the synthetic oil from the start would actually increase longevity, or is it your typical "which oil is better" argument?

johnarusso

Two thoughts. aisin makes a T-IV ATF fluid that is approved for this tranny and can be found (it's hard) for less than the Porsche branded stuff. Also, the Mobil 3309 is approved.

AS for the VB, you are on the right track. the solenoid modulator valves (A and B) are known to wear and Sonnax part 25741-18K will address this. They also make a kit for the K1 clutch control valve. Good luck.