Hey everyone. Decided to post this mainly due to some frequent redundant posts that keep popping up, and some FYI for those who frequent the site, as well as some newcomers.
Let me preface this by saying all information I am giving is from my personal experience, and there will certainly be some of my own opinion included. I am an ASE L1 Master technician specializing in Volkswagen/Audi, Toyota/Lexus, and Honda/Acura products, I will leave it up to the individual reader to weight how much my opinion matters. I know there will be some contradiction, so again take this for whatever you think it is worth.
First off, Volkswagen's wonderful "01M" automatic transmissions have never been very durable, and as of late have really started to fail quite a bit. This transmission, as it applies to TDI-powered cars, is used in '98 through 2003 NB, and late '99 through 2003 Golf/Jetta. I have no good news for anyone cursed with this unit. Of all the 01Ms I have ever seen, I have only personally
seen FOUR make it past 200k miles. Most start giving problems between 80k and 180k miles. Usually the problems start with a delayed reverse engagement, sometimes forward, and eventually just quit altogether if you keep driving them. Rarely do they just stop out of the blue.
I have taken these apart when I worked at Volkswagen, I have seen them break numerous hard parts, and I have seen them crack cases. I have also dealt with about a half dozen people who tried rebuilding them. I have never seen one last. The only "fix" I have seen for these is to buck up and purchase a VW reman unit. They are expensive, our shop charges about $4800 'out-the-door' for the unit. However, they do come complete with all new sensors and switches, new TC, new cooler, even come full of new fluid. Just swap it, clear the TCM memory, adjust fluid level, and you're done.
Some folks think there is some "quick fix" and if there is, I have not found it. They are just a weak design, just like the 096 before them (they actually share a lot of internal parts with the uber-POS 096!). And to replace parts of the 01M is a scary proposition. Parts like the valve body are expensive...the valve body alone is about $1300! The main reverse gear clutch set inside, which is almost always shattered, is around $500. You start adding all the parts up and it gets really expensive really quick, and then you STILL have no guarantee it will work, or work for long.
I have to say that these units rarely have the typical automatic transmission failure symptoms. Most of the time a failed unit's fluid is not all that bad looking, and there are not a lot of friction material laying inside the pan like you would expect to see. More failures are related to broken internal hard parts. I've seen chunks of aluminum and steel laying in the bottom of the pan that have NOTHING to do with how dirty the fluid is or is not.
Keep in mind this: I have seen absolutely NO correlation between frequent fluid changes or no fluid changes in terms of longevity. And even most of the failed units still have reasonably 'normal' looking fluid in them, and friction linings are rarely burnt up, which is the usual condition of a failed conventional automatic transmission. I do know every one I have ever seen that had non-VW (Pentosin) ATF added or changed failed very quickly...sometimes before the next oil change.
Update: there has been some discussion about valve body failures on these. This is nothing new, and may be the root cause of many of the problems. However, when you drop the pan and find large chunks of metal busted off from the main clutch drums laying loose in the bottom of the trans, I got news for you...a new valve body is NOT gonna fix the problem! Even if it caused
the problem, the damage is already done. However if you want to try this, and you do not see any large pieces of schrapnel inside the pan, there has been some mention of some sources for 'reman' valve bodies outside Volkswagen. I have no personal experience with these, so I cannot endorse NOR condemn this course of action. If anyone does, please let us know how it goes long term.
Since I have started this thread, at least a half dozen MORE threads have been started about a dead or dying 01M transmission!!!!
Update: even more failures! I have a .gif of Freddie Mercury (thanks Growler!) that I post in these failed 01M threads now...
Next thing I have seen is some failed engine controllers on ALH cars. Some others have had the same problem as well. Causes some seemingly unrelated DTCs to keep coming up that will not clear, and the engine will be hard to start, won't hardly rev up, and will white smoke heavily. I have had 4 of these here at the shop.
ALH disptick tubes can break. The issue seems MUCH more pronounced when people chuck the engine cover. Put it back on, it is there for a reason (several actually).
Seven times now I have seen the oil pump chain break, or its tensioner crack in half. Four on ALHs, two on later 1.8t engines, once on an AEG (early A4 chassis 2.0L gas engine...same part). All except the one 1.8t were higher mileage, 250k+, and two resulted in engine failure because the owner continued to drive with the oil light blinking at them
. This would be an easy thing to change during a timing belt on higher mileage engines, all you'd need to do extra is remove the oil pan, remove the front seal retainer, and it is right there. Chains do NOT last forever, despite what so many people think. Also, there is cause for concern for BHW engines (B5 Passat TDI) as these chains also run the dual balance shaft modules, and these
chains sometimes break BEFORE 100k miles!
Been seeing some VE pump failures, both leaks and internal breakage. Got one out to DFIS right now from a B4 that sounds like it was full of marbles. Please do not try and half-ass an injection pump repair. Spend the money and have it properly rebuilt. DFIS does an EXCELLENT job. PM me if you need their information. If your pump is making a loud, sharp, metallic "clicking" sound like baseball cards in a bicycle wheel, it needs to be rebuilt. If you let it go too long and the part inside that is making the noise breaks, it can DOUBLE the cost. So don't let it go. Another way pump failures can manifest is with hard starts, timing that will not stay put, injection control deviation DTCs, loss of prime (suction pump bad), and lots of smoke and low power. Even if the pump sounds fine, if you have these above symptoms it may also require a PROFESSIONAL rebuild. FWIW, on the ALH cars the 'clicking' sounds from the pump seem to be worse on late 2001+ cars. DFIS seems to think that Bosch got a bad batch of steel or something that was not tempered properly with that era pumps and the shafts beat out really bad often before 100k miles.
Seeing quite a few ALH engines' EGR valve vent holes spewing oil all over. My fix is to just replace the EGR/anti-shudder valve assembly, but some have figured out a way to open them up and repair them. Check for oily residue around the vent hole on the EGR, towards the oil fill cap. These can leak bad enough to run down and sizzle on the exhaust manifold, which can be a fire hazard.
A/C compressor clutches are falling off. While not really a new problem, starting to see more and more. Everyone who reads this needs to take a 14mm wrench right now and check the tightness of that nut on the front of the compressor clutch. They work loose, and the clutch falls off, the belt goes flying, and can damage the surrounding area. In two cases I have seen the accessory belt wedge itself under the crank pulley and derail the timing belt...with disasterous results, as you'd expect. A dab of red Loctite on the shaft threads can help if you find the nut is very loose. Otherwise just give it a little snug.
Seeing quite a few A4 cars' radiator cooling fans failing, as well as a few fan controllers. Good news, there is an updated larger [hopefully] more durable fan motor(s) available for these cars. It would not be a bad idea to upgrade now if your car has more than about 150k miles on it. It almost always seems when the fan dies (the melt and burn!) they also tax the fan controller pretty heavily, which can cause them to fail a week later. So I always recommend a new fan controller when I replace the fans. The dealers will stock all of this usually, and many of our great vendors here also keep them is stock.
Mirror heaters are burning up because people leave them on. That little symbol in the center of the switch is sort of a universal sign for a heating element, with a little mirror shape background. If the key is on, and that switch is in the center position, the mirror heaters are on. They are not timed, they will just burn out. Keep the switch in the L or R positions, and only use the heater when you need to.
Parking brakes: USE THEM!!! This is how the rear brakes adjust, and it also keeps the caliper free and working. In addition, to those of you with automatics (yes, this includes the DSG!) set the brake BEFORE you place the transmission in park...let the weight of the car rest on the brake, not the park pawl. Modern Volkswagens use a very flimsy plastic gear selector base, and these wear out and break apart if you have to use them to yank the weight of the car off the pawl. Go price a B5 woodgrain gear selector assembly....
I have also been replacing parking brake cables about a pair a week. This is an easy job, and an easy thing to inspect during your 10k rotation. Look for a bubbled up section of the cable where it rides under the swingarm on each side in back. Moisture gets under the sheathing, and causes the cable metal innards to rust and swell and pinch the cable in place.
The whizbang "DMF" has been an issue from the beginning...years before we saw one in a TDI they were failing in 1.8t Audis, and nothing has changed. While a great idea, they are fragile, and if they come apart, you can damage the transmission. I have had two blow holes clear THROUGH the bellhousing! There is a simple fix for these, to install a conventional one-piece flywheel like earlier A3 and B4 TDIs used. Same fix for failed DMFs in Toyota 2JZ-GE and GTE engines, same fix as Ford PS engines, same fix for Duramax engines. I actually had an IS300 DMF cause the snout of the crank to break off at Lexus! I would not say the DMF in TDIs is quite an epidemic level, but it is something I feel is worth mentioning.
Update: the DMFs in the 02E autoboxes (the DSG) are starting to come apart. Loud banging sounds from the bellhouse while at idle, mainly heard from underneath, are from the DMF coming apart. Many are failing while under warranty, but as usual the dealers are clueless and say things like "that is normal" and "the DSG does not have a DMF". Well, I am telling you that not only DO they INDEED have a DMF, they are perhaps even MORE failure prone that the ones with the manual transmissions. And there is no fix for them like there is for the manuals...although there have been some newer part numbers for them.
Smashed oil pans: do yourself a favor and install a skidplate, please! And yeah, I know it won't happen to you, that is what the last 5 people said to me too.
And they protect more than just the oil pan: http://forums.tdiclub.com/showthread...34#post2159034
...yeah, that guy needs a new TRANSMISSION too.
Seeing some failed lift pumps (PD cars only) that are in the tank. They are not expensive nor that hard to install. Listen for any unusual noises during the short glow period when the lift pump primes. This can cause a no-start or a long crank.
Another thing on the PDs that can cause a long crank is a flakey Coolant Temp Sensor (CTS). They behave more like the gassers do when the CTS wigs out rather than how the VE does. The engine will rarely record a DTC, but often times the Instrument Cluster will, so always check there too.
The B5 TDI, which was only sold here for 2004 and 2005, is subject to upper link (ball joint) and outer tie rod end failures, as well as frequent outer CV boot failures. This applies to all B5s, of course. Relatively easy repairs, but they require a special alignment fixture for 'raised toe" which almost no independant will have (I do!
) and dealers sometimes do not use.
The B5's 01V transmission is sourced from ZF, it is essentially a ZF 5HP19, and is a pretty good unit. I have not seen one fail as of yet.
I have seen a few A/C inhibit relays (control units) fail on the B5. They will cause the A/C compressor to not engage. Easy to replace, top of relay block in car, about $50 IIRC. Can't remember the control number of the top of my head, but if anyone needs it I can find it for them.
All the B5's BHW engines will need sooner or later the upgraded balance shaft module. They have switched from the troublesome chain driven unit to a proper gear drive unit. These things are getting noisy and in many cases breaking and can even cause catastrophic engine damage. Do not delay, GET IT UPGRADED!!!
Some cars' alternator's clutch pulleys are coming apart. I have seen more happen on later ALH cars with the Hitachi alternators, only one on a Bosch equipped car. There are a couple special tools to get these off the alternator shaft, and they can be really tight. Keep a watch (ear) out for any strange noises especially during high-voltage load demands.
As you probably all know, if the timing belt is in any way compromised on any VAG diesel, the valves WILL contact the pistons, and the head WILL need to come off. While this is almost never an issue with normal scheduled PM, good parts, and proper procedures, sometimes these get neglected or done improperly and disaster hits and the head needs to come off.
Let me say that I have never, ever had a VAG diesel head that could not be repaired and brought back to like-new serviceable condition for a reasonable price. And while it may seem like a quick and easy way out, the aftermarket replacement heads are of very poor quality. The castings are poorer material, the machine work is not as good, and the valves, guides, springs, keepers, seals, lifters and cams are JUNK. Especially the valves and guides.
If you can, keep the original VAG casting, have it rebuilt with OE parts by a reputable person (PM me for some references if you like) and you will be back in business. I am seeing these aftermarket heads pop up on used cars people bring me, and the cars are burning oil, making funny noises, hard to start, smoking, etc. And you pull one of these off and even after only 40k miles every single valve guide is WIPED OUT!!!
Take it easy on your dealer, if you have to go to one. If you go in there with a chip on your shoulder, that attitude will most certainly be reciprocated! I have worked on both sides, and I understand just how horrible a [Volkswagen] dealer service department can be, I left one because of it! But at least give them some normal human respect...even if it is hard...just be the better person.
On OBD (On Board Diagnostics): generic "OBD2" scan tools are useless. They are barely useFUL on anything, but really bad for VAG cars. They will either give you half the story, or no story at all, or maybe not even communicate at all. A VAG-specific scan tool will not only give you the FULL picture on the engine management, it will do the same for ALL the modules in the car...and there can be quite a few. TCM, ABS, SRS, CCM, radio, steering wheel, etc.
Using a generic scan tool is sorta like standing in the middle of a room and looking through a window to the outside and trying to see how many trees there are. If you can only see one tree, it may be because the others are simply out of view, NOT because there is in fact only one tree outside!
Nothing new, but becoming more and more of a problem it seems: the plastic water pump impellers are breaking apart. This causes major overheating in a short period and can of course ruin the engine and related bits. Please use cast iron, steel, or brass impeller water pumps!!!
The 02J manual trans equipped cars, which would be all A4 platform cars, have been having the reverse light switch connector wires breaking. Usually right at the connector, and this requires a new connector shell and a double ended 'pigtail' repair spliced in. Helpful tip: the brake pad sensor wire on the left front is the same one...so save your old brake pad connectors and you can splice them in!
Some A5 bits: the upper door skin bolts (I have no other name for them) are coming loose. Usually just the front doors, and usually just the upper ones. These are black T30 bolts, and you can see them easily with the door open, towards the hinge end of the inside of the door. A whole line of them going from top to bottom.
Also on the A5, trunk latches not cooperating (there is an updated design) and a couple SRS connectors under the seats sometimes need to be cleaned or replaced.
The A5 cars' Delphi radios have been having some issues, usually battery draining. Requires a replacement radio.
If anyone has anything to add, please feel free. I may add some more stuff as I think of it.