Audi A6 quattro 95 AT.

Hi,
My A6 quatro '96 (V6) started Automatic transmission misbehavior. The car has about 240Kmiles and until recently the AT was rather smooth. Lately when shifting from second to third gear the RPM goes up to
about 3500+ and then the 3rd gear engages somewhat rapidly causing the car to jerk. I brought the car to a "German Car mechanic" to have the fluid checked and to have the filter replaced. There is more dipstic on the newer models and I didn't want to do it by myself. I was concerned that the fluid level might be low. The mechanic changed the AT filter and to my surprise told me that the fluid level was too high. He refilled the fluid to proper level after the filter replacement. I thought that initialy the car behaved a bit better but after one or two more days I see that the problem hasn't really gone away. It's not too bad yet but I am concerned that it's the beginning of a more serious problem. I'd appreciate any comments about your experiances with Automatic transmissions on these Audi models.
Thank you,
Andre
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The 2.8L engine with 4-speed front wheel drive? That's the ZF 4HP18 transmission. I would say lucky for you to get a premium ZF transmission in there. Now there are cheap Aisin transmissions in Audis. But the cheaper VW are even getting Jatco transmissions!
If the transmission needs to last the ATF and filter needs to be changed periodically, even if the manufacturer doesn't recommend it. Most places, however, can't seem to do this correctly -- as far as fluid type and level. Sounds like whoever serviced it last did a poor job. Tell us who!
Even if the fluid is regularly changed, the clutch pack material will eventually wear as in brake pads. Sounds like this may be the case as you are slipping going into 3rd. The pressure rise may be marginal now to engage the clutch pack/brake bands for that gear.
So I think another ATF change or two in close intervals may help flush out the transmission. Perhaps consider a "High Mileage"ATF suitable for that transmission. A machine power flush is not recommended because it can send debris into valve bodies and other close-tolerance areas. Improved shift is probably all you can get now.
For example, *if* the transmission uses Dexron II/III, then consider Valvoline or Castrol High Mileage ATF: http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9018758&contentId=7033928 http://www.valvoline.com/pages/products/product_detail.asp?product=6
If high milage ATF doesn't work, then maybe sell it or drive it until it permanently slips?
On Apr 13, 11:19am, snipped-for-privacy@hotmail.com wrote:

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That said, if you really want to keep the car, consider dropping in a ZF SecondLife rebuilt transmission. Not just a cheap rebuilt from the lowest bidder.
You can locate such a original factory (ZF) rebuild from www.transtarindustries.com, an authorized parts dealer with international locations. And if in the US, find a shop belonging to the Automatic Transmission Rebuilders Association, www.atra.com. If you're across the pond, then I'm sure there are similar shops.
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John, Thank you for taking the time to provide me with a lot of helpful information. I live in Connecticut. I would like to keep the car on the road for a while, it is a great car despite some dissapointing problems. For now the slip only occurs during gear shift and it only affects 3rd gear. It's a shame the procedure for filling up the ATF is not quite doable without a lift ie the ability to lift the car and keep it horizontal. But I have a local mechanic whom I trust with my cars even though he is not the "German Car Mechanic". I have bought the car used about 3 years ago and the overfilling happened before my ownership so I don't know who the guilty party is. Your comment has referred to a front wheel drive car, my car as I've indicated before is a quarto.
This same car also has an annoying oil leak problem which drips over the exhaust causing a bad smell for a few minutes each time after the car has been stopped. The German Car mechanic who changed the ATF and discovered the incorrect ATF level, has also confirmed a prevoius diagnosis by a dealer that the oil leak is a head gasket problem. Which is very unfortunate.
Thank you again for your help. Andre
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Right -- the list I have must be out of date, didn't show AWD. Sounds like the previous owner could have taken better care -- tranmission slips and head gasket problem.
However, the C4 chassis still lists only one automatic transmission, so I can only guess it's still the ZF 4HP18. And if so, ZF lists Dexron III as the proper lubricant. In that case, I'd use High Mileage ATF mentioned to see how it may improve the situation. These fluids have more friction modifiers, detergents, and other ingredients for older transmissions.
ZF oil reference guide (the ZF.com one takes a long time): http://www.unofficialbmw.com/images/ZF_Oil_Reference_Guide.pdf
http://www.zf.com/na/content/media/import/zf_na/startseite/sso/passenger_car___light_truck/car_driveline/lubrication_and_oil_requirements_/Oil_Reference_Guide_PC_102307.pdf
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Thank you John. I crawled under the car the other day and confirmed that the transmission type is ZF 4HP18. I wanted to look underneath the car to see If I can spot any reason why I hear a rattling sound when the car is first warming up. Didn't see anything of concern. Unfortunately the noise seemed to be coming from engine/AT body. The noise goes away when engine warms up a bit. I did notice however that the last two (out of 4) plastic "quick lock nuts" on the noise shield plastic cover under the engine have been broken off. A technician in the "German Car Specialist" shop should know how to take the cover off an Audi without braking off any of the mounting clips. I get frustrated with this kind of stuff. Are there any mechanics left, who can take things apart and put them back together without leaving anything off or braking anything off. Maybe I am just too "fussy" for the times we live in...
I have been driving the car to work lately and I've observed that the problem with the transmission can be described this way. In case of all the gears except the 4th (highest) gear the clucth seems to release prematurely at RPM = ~1500. RPM rises quickly and the gear up- shifts. But now the higher gear is engaged prematurely at about 1000RPM and the car has very difficult time accelerating. Once in 4th gear, the car runs great, engine has a lot of power.
Thanks, Andre
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I'd prefer the ZF over the Aisin VW is putting into the Audis these days. Anyway, a good mechanic is always hard to find, even at the dealer.
As far as the cold-start noise goes, it's hard to tell what it is without listening to it. But typically lube or parts clearance related issues. More likely in the engine than transmission. If a thicker oil (for example, High Mileage oils) in the approved viscosity range then you know where it's located.
It's a surprise that the high ATF level you mentioned, because slippage is usually caused by low ATF level, among other things:
1. Low ATF level. Especially in the new 6HP series LePelletier designs, most mechanics can't get this right and tend to leave ATF fluid level too low. 2. Low or sluggish line pressure rise. Worn tranmission valve body/oil seals. (-> governor seal) 3. Plugged filter. 4. Improper transmission linkage adjustment
Just my 2 cents.
The following are from Alfa groups using 4HP18 series:
If the $4 Accumulator A spring for 4HP18 series mentioned in the Alfa club is of relevance: http://www.alfafaq.com/id16.html Who knows, maybe Nat Wentworth at Erickson Industries, if still there, may be able to help? ;)
Another one: From: Bill Jones Date: Sun, 15 Feb 1998 05:27:46 +1030 Subject: Model 164 ZF auto transmission woes - simple fix!
Symptom
Changes up early and haphazardly Sometimes changes down again almost immediately Sometimes a delay to go into reverse Some slight surging when driving in 3rd gear NOTE:- drives perfectly in manual mode!
Solution
After discussing the problem with a good auto transmission company, it appeared likely that either the valve control assembly OR the governor assembly would be the likely cause. They decided to look at the governor first and on disassembly (which can be done easily without removing the transmission from the car), found a broken sealing ring. These rings (two of them) are a split cast iron ring, very similar to a piston ring. New parts were ordered from ZF in Sydney and the box reassembled and tested. The car now drives PERFECTLY and is a pleasure to drive once again. It seems that insufficient oil pressure caused by the broken sealing ring caused the symptoms described above.
ZF part numbers are:-
Gear cover gasket ZF 0750-112-156 Ring sealing ZF 0501-306-310 Screw - 4HP14 ZF 1036-309-269
Total cost for this job was A$356.70 so for those 164 owners out there who are having similar problems, don't fall for the trap of having a change-over transmission fitted for somewhere around $5,000.
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