Diagnosing 01V Reverse Gear Issue for 2000 Passat 1.8T

[Passatster]

I've been dealing with a "no reverse" issue in my 2000 Passat's 01V transmission for almost one year now, and I'm still trying to narrow down the likelihood of the possible problems; given that the car is about 12 years old with 110K miles, I would like to avoid a major rebuild it possible.

Here are the symptoms, which have been very consistent since the problem first surfaced.

• On a cold start (no driving for several hours/over night), reverse will engage for a short period of time and then disengage. The car will shudder when moving into reverse gear, will move with throttle, then disengage shortly afterwards as if it were shifted into neutral. In this state, there is a small amount of constant drive force as the car will start to move in reverse from a full stop.
• On a warm start, reverse will never engage and no drive force is present.
• All forward gears engage and stay engaged as expected.

I performed a proper ATF fluid and filter change and noticed no unnatural debris (transmission parts) in the ATF pan during the process. Furthermore, scanning the TCM with a VAG-COM yielded no stored errors. I also used the VAG-COM to observe the motion of the N88 solenoid during shifting and it appears normal, though I didn't observe the pressure-control valves N91 and N93 (the manuals states these are the three valves that operate when in reverse); the multifunction-swtich also appears to be operating correctly as it doesn't slip when selecting reverse.

I've read about the d-drum issue with the ZF 5HP19 transmission (manufacturer labeling for the 01V transmission), but I don't think that is the problem since I can engage in reverse for a short period of time.

What could be the possible cause of this problem and what can I do to further diagnose the root cause? Has anyone else had a similar problem and resolved it?

[CoolAirVw]

What could be the possible cause of this problem and what can I do to further diagnose the root cause?

Here is your next step...

remove transmission from the car. Disassemble transmission.

[blackarachnid27]

did you ever figure out what the issue was, my 00 a4 1.8t is doing the same thing

[footpounder]

I recently would shift into reverse, It would partially engague, Then POP out for 1-2 sec and reingague and all was well. After just a few instances of this It got pretty fierce so it got parked. In searching the web I found this-

http://www.searchautoparts.com/motor...w-audi-and-vw#

We pulled the valve body to reseal and check everything and found the D-clutch accumulator cap was popping out where you could see the oring with out pilling that cap! It fixed it! We also took alot of pictures so we could put it together as we found it! We took a Good Pix of the valve body plate with all the springs, check balls and orfices in place-printed the picture-put clear plastic over it and layed all the parts out on the pic exactly where they went.Even used a sharpy to write notes. but you may not need to pull apart the whole valve body if you diden't want just pull it off the case and pull the piece off in the link above.

[Revmax]

No reverse can be attributed to a worn out pressure regulator valve in the valve body. It is possible that is causing the issue.

[CoolAirVw]

No reverse can be attributed to a worn out pressure regulator valve in the valve body. It is possible that is causing the issue.

How so?

[Revmax]

How so?

Reverse utilizes both stages of the PR valve. It does this by rerouting balance oil to the balance side of the valve. Now, if the bore is severely worn the rerouted balance oil will leak past the valve and not allow full line pressure to be available. Symptoms would be delayed reverse, loss of reverse or slipping reverse.

[CoolAirVw]

Interesting.. nothing wrong with that, but I would be more likely to attribute a reverse issue to

1. broken piston
2. snap ring broken out the drum,
3. the 0-ring issue linked to above
4. a rolled drum seal

1 & 2 are common issues I've seen in my shop multiple times in the last 2 years, plus its scattered everywhere across the internet

But... certainly a worn PR valve can lead to broken piston and broken snap ring out of the drum.

Some of the ones I've done have been terribly worn, and I attribute most of the common issues like 1 & 2 above and spinning out the pump bushing to excess pressure. All my 01V rebuilds get oversized PR Valve.

#4 happened just last week but someone else had been in that unit before and I assume they rolled it when they worked on it.

[Revmax]

Yes, I agree with your comments above. Normally the reverse issues surface from the worn out PR valve. Now, it just depends where the wear is happening and what the result of the wear causes. We could have high line, low line, high cooler flow, low cooler flow or a combination of all.For customers that have the high line issue if they continue to drive the car it will eventually blow the drum / snap ring out. Great comments by the way!