monkeytronic

I'm in the midst of planning a complete change of every fluid in the '02 A6 4.2 as it's now at 80k miles and I'm wondering if there are any issues to be had with installing an aftermarket oil-to-air ATF in series after the factory oil-to-water ATF cooler in the radiator so that both coolers will be plumbed in series.

On all the other cars I've done this on, notably older Fords and newer Volvos (the latter sporting GM-sourced transmissions) that use either Dexron-III or Dexron-VI ATF, I'd just install the aftermarket ATF cooler and be done with it but with the A6's ZF-sourced 5HP24 (code FUL) automatic I'm wondering if there'd be problems considering that the transmission uses the VW/Audi ATF spec is G 052 162 A2 AFAIK and the transmission is filled and the ATF level checked from under the ATF pan at a specific temperature which IIRC is 30C (86F).

Basically I'm worried if overcooling the ATF will be an issue. FWIW I'd plan on installing a stacked-plate ATF cooler similar to the usual B&M Racing or Derale unit featuring an internal fluid bypass and no external thermostat unit of any kind. So far I've gotten at least 176k miles out of a single transmission with the added ATF cooler and regular ATF changes so I'm hoping for the same kind of success with this A6.

Audi42LV8

I don't think that over-cooling could happen. I mean, thats an upgrade. A transmission oil cooler is beneficial. Heat is like 75% cause of transmission failure. Thats from a my transmission mechanic, personal shop mechanic, and Audi dealer mechanic. Heat is hell for a transmission, so for me here in AZ It would do great deal of help.

I am going to install a ATF Cooler and Engine Oil Cooler. Both would be a great benefit to the car. I am also installing this on a 01' A6 4.2L, after a rebuilt transmission. After this rebuild, I wont worry about anymore issues cause I had the updated parts from ZF & Audi installed which makes it more reliable than it was in 2001 when it was new. Plus, I got a new torque converter and all seals in and on tranny are replaced. Plus, new clutch packs and watever else is in there got rebuilt. But an tran-cooler would be good.

4Driver4

Why bother? Factory cooler is more than sufficient.

Kris Hansen

I agree, except in cold climates, it could keep the oil from warming up enough, which could be worse than too much heat.

Euconect

If you add and extra cooler to the one you have right now you will see drop in pressure of your fluid and that can effect the way transmission works

Audi42LV8

Alright. Ef the tran-ATF cooler.. Can I add a engine oil cooler without anything bad happening?

4Driver4

Why bother? Comes from the factory with one already. More than adequate. Just drive and enjoy.

Audi42LV8

Makes sense.. Will do with a rebuilt tranny :P