Silver90Quattro

No problems, other than earlier this week PRND lit up in instrument cluster and it through a code:

18243

P1835 Pressure Contr.Solenoid 5 Short to B+

Cleared codes on Monday, seems to be ok so far (almost one week later). No further issues with PRND, no shifting issues, etc. I THINK it MAY have been just moisture as it rained earlier this week, and the drains are probably clogged from the fall leaves, letting water into TCM/ECU area. Car is currently owned by a very good friend, and I am pretty sure I am going to purchase it from him.

We have no record of the trans fluid and filter being changed, but I really want to change it if purchased.

At 180,500 miles, is this a good idea or bad idea (if I follow audipages.com and Bentley procedure).

With no driveability issues, and regular (from here on out) service, are these transmissions reliable, or do I have a ticking timebomb?

I've been reading the forums, and it seems like the trans is the weak link in these cars. Do they give any signs of failure before they let go?

Opinions/advice appreciated, as I am more familar with 1995 and older Audis! This A8L is a step up for me!

Thank you,

-Brian

silverd2

Different opinions on this...If it has never been serviced, the atf filter would be my main concern. Would NOT do a full flush..very chancy on an old trans, without a known service history.

An atf change (like Audipages procedure) would at least get a new filter in there and assure proper atf level.

Some advocate (and this has some merit) only changing the filter and replacing the same old fluid, IF a high mileage trans has NEVER had an oil change. MANY disagree with this (many don't)...but the theory here is that much of the friction work in the trans "may" be by built-up "sediment" on clutches that can be washed away by new detergent present in new atf.
A filter change alone allows full flow again and takes the stress off the pump...assuring full pressure through the valves that shift gears and engage the TC clutch.

Opinions vary widely.

As I understand, the trans's in later D2's (02-03) are statistically more dependable than earlier models...esp, before 2000.

Plus, I would look in the E-box to check for moisture (past or present) or corrosion...I would NOT assume (but possible) that caused the code. If it wasn't the TCM or external wiring connection on trans, that solenoid/valve/wiring harness is accessible without removing the trans...it's in the valve body behind the atf pan, where the filter attaches.

Silver90Quattro

SilverD2,

Thank you for your response. I have read a lot of your posts, all very informative and helpful. Thank you. A few questions:

"Different opinions on this...If it has never been serviced, the atf filter would be my main concern. Would NOT do a full flush..very chancy on an old trans, without a known service history."

What do you mean by NOT do a full flush? What is your definition of a full flush?

"An atf change (like Audipages procedure) would at least get a new filter in there and assure proper atf level.

So, do a filter and fluid change per audipages?

"Some advocate (and this has some merit) only changing the filter and replacing the same old fluid, IF a high mileage trans has NEVER had an oil change. MANY disagree with this (many don't)...but the theory here is that much of the friction work in the trans "may" be by built-up "sediment" on clutches that can be washed away by new detergent present in new atf.
A filter change alone allows full flow again and takes the stress off the pump...assuring full pressure through the valves that shift gears and engage the TC clutch."

So, change the filter and fill with the OLD fluid, as per audipages.com/Bentley? I can see the thinking behind this. The cleaning action of the new ATF could possibly do more harm than good...

What would you do? New fluid or old fluid?

Thank you for the clarification.

silverd2

First remember: Opinions vary widely...I am no auto trans expert...the only part of any car that I've never repaired. On my car, at about 100K miles, I did a simple atf and filter change...half out of curiosity and had a small issue (occasional hard shifts from 2nd to 1st, not there before). I found my filter restricted, but fluid not burnt, shifting was smoother in general afterwards. I considered putting the old fluid back, but already had purchased a kit with atf...decided to use it. I did not drain overnight (gets more out)...didn't feel the need, so mine drained and refilled with 7 liters (9.8 liters is factory fill)..some stays in the trans, trans cooler, but most that doesn't drain stays in torque converter.

"What do you mean by NOT do a full flush? What is your definition of a full flush?"

A flush can be done different ways: anywhere from forced backwards through the trans with a machine, to machines that let the trans run all old fluid out under it's own power (engine running) while pumping new back in until clean and new (often taking near twice the trans's capacity of atf to do the job) or a "home" flush, by changing atf twice in a row, getting most of the old out...taking lots of fluid and accomplishing little more than a simple drain/filter change. Flushes are generally done with atf only, unlike a chemical flush done on coolant/radiator.

Most agree that too thorough a flush on an old trans with burnt atf is bad idea, asking for quick failure...a filter change is always a good idea.

NEVER just drain pan fluid and leaving old filter...more harm than good...will just further clog an old filter when new fluid starts cleaning the trans internally.

As for other questions...In a really high mile trans, if I found really burnt fluid, I might be more likely to put the old fluid back in with a new filter and pray for few more miles. Burnt fluid indicates internal problems already.
My fluid was in good shape at 100K miles, looked OK, smelled OK and felt OK...with no real sludge (a little "slime") on the bottom of pan and only a little fine sediment on the pan magnets...so I felt good about my trans and had no fear of replacing the 7 liters that drained with new atf.

Hope this helps, but still just my opinion...formed mostly from all I've read and talked about with other home and pro mechanics.

tozoM8

If it shifts fine, I would just leave it alone.

silverd2

BEST advice from the one who knows the most here.

pocketchange

Is (VERY) good when it comes to (ALL) fluids.

Keep in mind Audi and Co., are in sales (service be damned) and would
love for you NEVER to service your transmission or whatever else.

No agenda.. says who?

Many (aftermarket) fluids have improved performance because they are not
produced under budget concerns. Chemical technology moves forward daily.

Remember the 70s when DuPont WOULD NOT qualify teflon as
an additive. NOW you have to order & wait (i know for a fact).

By all means, enjoy your Audi and NEVER service anything as long as it is working.
Audi & Company will be very happy to sell you another.

silverd2

Nice editorial there, but all old news...No one here said NOT to ever service anything.

The point was that when dealing an A8 with 180K miles on the trans, no records and no trans issues, why mess with it...at that mileage in these cars, you're lucky it's still shifting and probably on unavoidable borrowed time...an oil change is unlike to change anything...maybe just open a can of worms.

It ain't no spring chicken...and 90 yr old men DON'T get prostate surgery...they just enjoy the time left, without painful (complication causing) surgery