Pentosin ATF alternatives
 

This is just a callback to this topic. Gabor has done a couple of transmission rebuilds for me recently and he indicated that the Mobil 1 and Valvoline synthetics (with the Audi approval) are reasonable substitutes for the OEM Pentosin that's so expensive and hard to source.

He is the final say as far as I'm concerned as the last several rebuilt gearboxes are running non-Pentosin with no ill effects.

tom

Ravenol would be another choice and certainly meets the VAG published spec.

The spec (from 20 years ago) was a semi-synth so I think the modern synthetics surpass it easily. Even Walmart's Dexron 6 / Mervon LV / Multi-vehicle ATF hits that spec.

170K miles since I bought my car (it had 114K when I purchased it) and used Mobil 1 Fully Syn ATF at 40K mile intervals. My slushbox is showing it's age, but the fluid hasn't caused any problems for me. At this point in my car's life, I think the transmission will continue to limp along until ALL the clutch fibers are worn to paper thickness.

Sounds good. I drained and refilled my A8's trans pan maybe around 100K miles (bought with 80K on it) and I added Red Lubeguard at the time. I used a semi-synth that hit the OEM spec, I do not recall the brand. at 165K I did the TransGo Valve update, at that point I was thinking the trans was in trouble, some rough downshifts and other oddness. When I did that job a refilled with Valvoline Maxlife ATF and more Red Lubeguard. The valve cured the oddness and the trans is still working now at 185K.

I had my S8 as well at that point, bought to replace the A8 but the A8 never stopped going. I put a TransGo valve into the S8 as well, and I was surprised that at 108K the S8 had a more worn valve body than my 165K mile A8, but maybe it sat in traffic a lot, plus the A8 is almost never used for short trips. Or maybe the LubeGuard helps reduce the steel-on-aluminum wear in those valve bores. I added lubeguard to the S8 trans as well when I did the TransGo valve in it. Also running Valvoline Maxlife ATF.

ATF
 

I've had a Allison Spec ATF in my A8 for years with no issue (other than the $'s, which is ridiculous..) pc

Schaeffer is in mine
 

July of 2016 at 162k Gabor did my transmission and used Schaeffer. Zero issues since then.