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Hi folks...need a little help here please. My vehicle is at Audi right now...but this one is making them think. 2002 Audi S8, 240,000miles, Transmission oil and filter was replaced with full AMSOIL synthetic around 135,000miles. Run great till now. Right now it acts like it is low on trans fluid... but its not. Reverse is fine and has power. Forward it wont start to engage until you bring up the RPM then it will slowly engage. I was driving the vehicle and everything was perfect. Got to a destination and put it back in gear to drive away and it started to do this slipping thing. On the hwy when I gently got it up to speed it wasn't reving any higher, I just really didn't have much power. Any Ideas? I was thinking torque converter, but they say probably not because reverse is fine with power.
Thanks...
Most likely? Internal seals that hold pressure to the clutch packs. It's pretty common on these 5HP ZF gearboxes that were used in the 97-03 A8s and S8s. But, it means an expensive rebuild or a replacement. I wish there was a better answer for it... but...
And, it's very common between 110K and 150K miles, so you are in the sweet spot for the failure. I'm in the same boat. I have a gorgeous Ming Blue A8L (2001) that runs great in reverse, but can hardly pull itself forward on level ground. So I'm off to Chicago next week to get it rebuilt.
Did you make small cutouts in the bottom of the transmission oil filter pickup tube? I wish I had an acutual picture of my filter handy, but when you install the pan, the bottom of the pick up tube is very close to the pan bottom if not touching it. The pump could be starving for fluid. Every time I have changed my tranny fluid I make these relief cuts using a Dremel and a 1/2" sanding drum. I make THREE relief cuts about 3/8" tall spaced equally around the circumference of the pickup tube. As of this morning, I have 273K miles now on my daily driver.
It's a cheap thing to look into compared to a tranny rebuild. I know that AMSOIL is supposed to be superior to other oils, but if you only change your fluid every 100k, you are probably are looking at a broken internal seal or O-ring. It just takes one to break to make the entire transmission malfunction. I have changed my tranny fluid every 35k on average since I have owned the car. I only use Mobil 1 Fully Syn ATF. I'm always amazed at how much stuff comes out after each oil change. Currently, my transmission is strong, but my torque converter clutch is definitely at the end of it's service life. At 70 mph, my TCC will cycle between locked and unlocked when I drive on rolling hills. I only know this because I can feel the distinct slippage. If one of my other clutches was bad, it would slip during acceleration or not even engage.
BTW, I've been on a road trip all the way up to Banff and drove through Calgary. Beautiful country you have up there.
Last edited by spitanddirt; 08-30-2018 at 06:34 AM.
It's my understanding that cutting off some length from the pickup tube is often necessary because of a filter/pan mismatch. On my 97, it was an obvious mismatch because the pan would hit the tube before it would touch the gasket. I simply sawed off about 3/4 inch. Your practice seems aimed at a less obvious mismatch. Thanks. Does the trans make a whining noise? Somewhere I read that a restricted inlet would cause the trans to whine, due to the pump cavitating. A plugged filter was suggested as a common cause. A pickup very close to the pan would cause the whine as well.
It's my understanding that cutting off some length from the pickup tube is often necessary because of a filter/pan mismatch. On my 97, it was an obvious mismatch because the pan would hit the tube before it would touch the gasket. I simply sawed off about 3/4 inch. Your practice seems aimed at a less obvious mismatch. Thanks. Does the trans make a whining noise? Somewhere I read that a restricted inlet would cause the trans to whine, due to the pump cavitating. A plugged filter was suggested as a common cause. A pickup very close to the pan would cause the whine as well.
I believe my transmission may have been removed and set on it's pan which caused it to deform upward. My transmission did whine a little when I first bought the car. I only noticed the deformation because the pan was hitting the oil filter and causing installation of the pan to be a little weird.
Did you make small cutouts in the bottom of the transmission oil filter pickup tube? I wish I had an acutual picture of my filter handy, but when you install the pan, the bottom of the pick up tube is very close to the pan bottom if not touching it. The pump could be starving for fluid. Every time I have changed my tranny fluid I make these relief cuts using a Dremel and a 1/2" sanding drum. I make THREE relief cuts about 3/8" tall spaced equally around the circumference of the pickup tube. As of this morning, I have 273K miles now on my daily driver.
It's a cheap thing to look into compared to a tranny rebuild. I know that AMSOIL is supposed to be superior to other oils, but if you only change your fluid every 100k, you are probably are looking at a broken internal seal or O-ring. It just takes one to break to make the entire transmission malfunction. I have changed my tranny fluid every 35k on average since I have owned the car. I only use Mobil 1 Fully Syn ATF. I'm always amazed at how much stuff comes out after each oil change. Currently, my transmission is strong, but my torque converter clutch is definitely at the end of it's service life. At 70 mph, my TCC will cycle between locked and unlocked when I drive on rolling hills. I only know this because I can feel the distinct slippage. If one of my other clutches was bad, it would slip during acceleration or not even engage.
BTW, I've been on a road trip all the way up to Banff and drove through Calgary. Beautiful country you have up there.
Thanks very much for your help... and Yes Banff area is very spectacular!
08-29-2018, 01:25 PM
Transmission issue
