auto tranny filter change / other?

[alsehendo]

Any good info that might tell me how to service my 412 automatic. It works OK but I am sure autos must need something patriotically besides basic oil every xx,xxx.

I know The "old fashioned" way to change ATF is to drop the pan, drain the transmission, replace the filter, reinstall the pan and refill with fresh ATF. Though better than nothing, this approach can leave up to two-thirds of the ATF trapped inside the torque converter (unless the converter has a drain plug, which few do--DOSE MY 412 ?).

What normally also should be done and how often on my 412?

[raygreenwood]

The only other thing I have ever seen other than what you just described as a normal filter/oil change.....is a full flush. Some shops you to offer this at a semi-exhorbitant price. In a relatively high milage tanny it may well be worth it. The object is to change fluid. Leave the filter in if its not dead clogged. Drive it until wramed up. Drain fluid again. Drive till warmed up...drain fluid and change filter then fluid. The object here is to get the fluid you can't get out.....heavily diluted with fresh fluid. You can see the price and labor issues at work here.

If you chance to have your tranny out of the car....ther are several things it MUST have every 7 years or 70K miles...or you are playing Russian roulette. It needs new gaskets and o-rings at the case joint between the gear ection and the diff. If not....when they fail (not if...they ALWAYS fail 100% of the time)....it will destroy your tranny in about a mile...irreperably.

If you are not taking it out...and even if you do, after re-installing, get the Bentley brown tyoe 3 manual...and a suitable set of gauges and do the main pressure adjustment via the modulator valve. Ray

[JimFarb]

Don't forget to check the level of the gear oil in the differential. And if you take out the top plug and oil comes out you probably have a leak between the trans and the differential. That happened on my 412 and KOed my differential before I could figure out why the oil level was high.
Jim

[raygreenwood]

Yes...this is caused exactly by the main shaft seal between the differential housing and the transfer case....that I emntioned in my other post. It was a problem not only on the aircooled VW automatics...but on all VW, Audi and most other Borg warner type boxes of theday. It was not a design failre (as its no different than any front wheel drive tranny)...but more of an issue with the available seal material of the day. They just did not have a material in those days that was excellent for both Dexron 2 type fluid and hypoid gear oil. These days, it may even be the fluid formulations that let seals live longer.
The recommended interval is 7 years or 70K miles. Whichever comes first. As Jimfarb noted...it WILL detroy the differential. Ray

[alsehendo]

7 years or 70K miles...or you are playing Russian roulette. It needs new gaskets and o-rings at the case joint between the gear ection and the diff.

Ray are you saying you need to remove the trany every 7 years or 70k miles?

Can AAMCO do a good job @ doing a filter change and oil on these?
Do they have a better way to remove more old oil?
Dose the torque converter have a drain plug on it if not would AAMCO have a way to get it out?

Spring is here and time to drive it again but I think I should do this or get it done!

[raygreenwood]

Yes. This was a major problem with all VW and Audi...and many others...that have both hypoid gear oil and transmission fluid in the same case. At least in the 70's and early 80's...there was not a common seal material taht was good for both oil types. So, they put in the best material they had and just planned to do a seal job at an appropriate interval.
There were lots of cars that had no problem...and even some of the German ones. But...this was by design. You will see some trannys that have two seperate seals between the differential section and the transfer case...both of different materials.
Yes, new seal materials may make this not have to be done on our old trannys...but how do you know what material to get. This issues gets exacerbated in hot humid climates. Thats also why some people can look at you and say...but I ran my 412 with automatic 100K with no issues on one set of seals. They got lucky, or didn't drive much...or lived in cooler climate etc. When the seal fails between the two case halves.....you can last a few hundred miles...or kill it in 10 miles...depends on how bad the seal failure was and how fast the fluid mixes. I destroyed one in roughly 10 miles this way. I could feel the odd shifting when I started off and didn't know what to look for. The tranny downshifted from third to 1st by itself at 65 mph when teh valve body failed. It shredded the differential because the hypoid oil was contaminated. Ray