[MNBoxster]

Hi,

Last year when prepping my car for storage, I discovered that the Gasket around the ATF Pan on my Tiptronic was leaking. The issues here are two-fold; first, you have smelly fluid dirtying up the underside of the car, but more importantly, as the 5HP-19 lacks a diptick, there is no easy way to determine whether your fluid level is dangerously low. Late last year, especially on hot days, I did notice a slight degradation of the Tranny's shifting - a possible indicator of low fluid.

So, I bought the Gasket and Filter in preparation of repairing it this Spring. What I didn't do was buy the ATF Fluid to replace that which I'll drain off when removing the Pan. This is because the Fluid - ESSO LT 71141 is extremely expensive (as much as $55/Litre) and only available in 20L containers - $1,100! I decided not to shelve that much cash for the Winter.

In the interim, I have been doing much research into this Tranny and the unique fluid it employs. It turns out that this transmission - a ZF Getriebe 5HP-19 A 86.00 (A 86.05 for 2.7L and A 86.20 for 3.2L 'S'), or some very close variants, are also used by Audi, BMW and Jaguar. All these manufacturers, like Porsche, claimed that the Fluid was 'Lifetime' (the LT in ESSO LT 71141 stands for Lifetime). And that a Fluid and Filter change was not due before 90k mi. But, recently, both BMW and Jaguar have revised their Service Interval and lowered it to 40k mi., whether Porsche will follow suit remains to be seen, but I plan on adopting the revised Service Interval, because in my experience, ATF usually had a change interval of 15k mi.

The key here isn't so much a breakdown of the ATF as much as it is removing the sludge, metal shavings and clutch material (the 5HP-19 A 86.00 employs 5 internal clutches - one for each gear with 5th and Reverse sharing one as they reside on the same shaft) from the fluid supply.

Several people looked for, or were touting cheaper, more readily available, ATF alternatives to the ESSO LT 71141. Also, since the Filter/Fluid change only resulted in the loss of 7L of fluid at most, many were averse to having to buy it in 20L packaging (espec. @ $55/L). The most common alternative fluids were Pentosin ATF1 and Audi's own ATF (which is just repackaged Pentosin). This fluid could be had for around $25/L. Another alternative was Redline D4 ATF, Synthetic and about $11/L. Each of these showed it was compatible with ESSO LT 71141.

But, from the ZF Getriebe site directly, there are no approved alternatives to ESSO LT 71141. In the dizzying world of Hydraulic Actuators, Electro-Hydraulic Clutches, etc. that make up today's modern Automatic Transmissions, often a specific fluid is approved for use and using any other can cause accelerated wear, poor shifts, higher operating temps, etc.

Since I would not be draining all 15+L of fluid from the tranny (incl. the Torque Convertor), any alternative fluid would give me a mix of about 50/50 ESSO LT and something else. I did not find this alternative too attractive. I was still averse to buying 20L of the stuff for a 7L job, so I continued to research sources of supply for the ESSO LT.

It is commonly available in Canada in 1 L bottles and at significantly lower prices, but Trade Barriers prevent it's importation. Exxon-Mobil is the Parent of ESSO, so I called the local Exxon-Mobile distributor and was again told it is available only in 20L containers, but at a Will Call price of $25/L, better, but still waay too high for what amounts to only ATF - not some Magic Youth Elixer.

I started researching BMW, Audi and Jaguar aftermarket parts suppliers and found two which sell it in 1 L bottles - 1 for $18/L and another for $13/L. So, I ordered up 7L of the stuff, along with 2L of ATE Super Blue Brake Fluid. I bought the $18/L stuff because this Co. offered Free Shipping on Orders exceeding $150 (which is why I threw in the ATE - 26lbs. total shipping weight) and resulted in a lower NET purchase than the $13 stuff w/ S&H.

Anyone wanting this info., just PM me and I'll supply it. In sum, I think it's better to do the Filter Swap and Fill at 40k mi. rather than the Porsche recommended 90k mi. for increased Tiptronic health and expanded lifespan. The procedure is relatively simple and I plan to photo-document it and post it in the DIY section in the coming weeks. Hope this helps...

Happy Motoring!... Jim'99