2000 Eurovan - 01M valve body - Loss of reverse questions

[Michaelryanosier]

My van had exhibited typical Eurovan transmission symptoms such as intermittent hard shift from 2-3 and when shifting to reverse took progressively longer and longer to make the shift. Recently I had to begin giving it a little throttle to get it to shift to reverse. Then I was mid reverse backing up when I felt the same feeling as when shifting and the car coasted to a stop, never again to reverse with it's own power. I had been pushing it backwards and making strategic forward facing trips until the weather has now turned warmer in Michigan. I had checked the trans fluid level and it was down about 3/4 of a quart. After topping it off until coming out the overflow tube I can almost feel the van wants to reverse but just doesn't make the shift. The van also recently overheated on a road trip when the coolant pump housing cracked in frigid Minnesotan temperatures, likely may have been the last straw for the transmission...

Last weekend I pulled off the trans pan, pulled the trans filter off and opened it up. It had an unconcerning amount of material inside...some very very small metal shards but mostly black carbon chips / flakes. I'd say about a tablespoon worth of crud. The van has 216,000 miles on it.

I see 01M valve bodies with solenoids listed for rather cheap ($100-150) on ebay but they are mostly from China and listed for Golf / Jetta / Beetles. However the casing stampings match ("01M 325 283 A" as well as "9220 101 BDT") and have the aluminum slotted end plugs for the K1 actuator valve. Is there any reason why one of these cheapos wouldn't be ok to swap to see if the valve body / solenoids / valves are my culprit? From my research VW used the 01M VB for the Eurovan and all it's other vehicles, is there any reason why the Eurovan 01M would be different? I'm not opposed to purchasing a rebuilt VB or having my VB refurbished with oversized valves but don't want to pay for that expense (500-650$) if it may not even be my problem...

Or are there any other symptoms / tests / diagnosis I can look at as for my reverse problem?

Thank you!

[trunnion]

You can measure the ATF line pressure to determine if your valve body is worn out. There's a threaded measurement port right next to the ATF fill tube:

I wouldn't use a 01M valve body, as there are subtle differences in the programming between 01M and 01P. Get yours rebuilt if possible.

[Michaelryanosier]

Oh, good idea, that jogged my memory that I came across this video which explains how to check that pressure:

https://www.youtube.com/watch?v=USKeGcariLU

Sounds like the threading for the pressure port is M10x1

I'll have to obtain such a device and report back later.

I should note too that I have a scan gauge II (to monitor transmission fluid temps) which indicates I have a P0740 code which apparently could be from any number of reasons... torque converter lock up / low fluid / over heating ...all of which seem plausible to have happened.

[Snort]

If you want a rebuilt valve body this guy sells them and he has some youtube videos explaining some of the 01P/01M issues.
https://www.importperformancetrans.com/index.php?l=product_detail&p=5441

[EuroTec]

P0740 is most likely a failed N91 solenoid, no 4. Little chips of metal and stuff is clutch pack material. That transmission needs a rebuild. ...jus sayin.
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If it ain't broke, don't fix it!

[SambaBurnsRed]

[Michaelryanosier]

Below are images of what is inside the trans filter... There were no metal shards on the magnets in the pan so the filter was working well. If I were to rebuild the transmission it would likely need the valve body anyways so I might as well start there. Given the rusting on the van I'm not sure if it would be worth a trans rebuild unless I could pull it off myself. Plus I fear the van might have a blown head gasket but figured it's not worth messing with if the trans won't reverse (the motor seems to be running ok otherwise), I'm trying to start cheapest and work my way up. I did acquire an engine hoist though if it comes to that, the van is relatively worthless in it's current state so I might as well tear into it and learn.

I have a question about the difference between 01M and 01P... the casting on the valve body indicates it is an 01M. But did all the EuroVans get a valve body / transmission 01P that is different from other VW models and they just used a 01M valve body casting?

Trunnion mentioned subtle differences in programming...is the Transmission Control Module programed for a 01P which is in my van conflict with a 01M valve body? Rebuilding my current one would likely be worth it, I just want to know theoretically and also have some knowledge when I talk to a rebuilder to make sure I get the correct rebuild I need. Or if the casting indicates an 01M is that the trans I have?

And Yes, I have seen all of Import Performance Transmission's videos on youtube, great stuff and worth going with them for putting that content out there for everyone!

Image of my valve body casing with stamps "01M 325 283 A" and "9220 101 BDT"

Image of material mixed around to see what's hiding

Initial image after filter is separated

[Michaelryanosier]

I tested the pressure:

Forward Idle: 1.2 bar
Forward 2000rpm: 4

Reverse Idle: 0
Reverse 2000rpm: 0.2

So much lower in both drive and reverse. The wheels would spin if I let off the break in drive, but nothing for reverse.

I removed the valve bode to inspect. None of the valves feel loose. The ribbon tape seems to have been replaced since I was able to remove it and it didn't crack and feels pretty supple.

I'm going to take it into my work where I have an air compressor test the valves and see if they hold pressure. I came a cross a video which explained to apply the air below the check balls and see if the valves actuate well or not. Is this the correct procedure?

Can I check the solenoids with a volt meter? I'll have to research on that.

Presuming these checks pass...would that then indicate the valve body is ok and perhaps my transmission pump is worn out? ...would there be any way to confirm that other than dismantling the transmission?

[TheOneTrueQuux]

[Stripped66]

The 01m/01p energizes the same solenoid (EV3) in reverse that drive-1st and 2nd gear uses, so if solenoids were the culprit, you likely wouldn't have any pressure in drive. Similarly, if it were damaged seals on the solenoids or transfer port, I'd argue you'd still see an appreciable increase in line pressure with RPM in reverse. 0-0.2 bar indicates a huge leak.

Given how little pressure builds up in reverse at elevated RPM, I'd suspect the pistons for the B1 brake and/or K2 clutch are damaged. Manual 1st gear also engages the B1 brake, so if the line pressure in manual 1st was also 0 bar, that might narrow down the damage to B1 apply piston.
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[Michaelryanosier]

Over the weekend I borrowed a friend's air compressor and applied air to the bottom of the transmission valve case passages. It sounded like all the clutch packs were activating...I could hear a noise when the air applied and then I'm pretty sure a noise of the clutch spring returning the clutches when I stopped the air. However I couldn't tell if that was just the noise of the pressure stopping kind of like a when abruptly turning off a water valve when flow is active, (a water knock except in this case an air knock). Was this the correct testing procedure?

I checked the resistance on the solenoids of the VB and they were all in spec except Solenoid EV-7 (N94) (Used for 3rd and 4th shifts) was reading 51 - 89 ohms and jumping around (Spec is 55-65). However I had not had any major problems shifting into 3rd and 4th. (Occasionally a hard shift from 2-3rd...which could be this. 3-4 was always fine). But not my reverse or low pressure readings problem.

So I am thinking this would narrow my problem down to the transmission pump itself...but that doesn't make sense given my pressure readings of 1.2 and 4 bar in drive at idle and 2000rpm respectfully, and 0 in reverse. Though maybe it is making just enough pressure for drive to work but not reverse which runs at a higher pressure?

I'm thinking of pulling the transmission out and opening it up since that is a free check. Instead of spending $700 for a valve body rebuild which seems to have passed its diagnostic check for the (most part).

I removed the plugs and checked all of the valves / plungers in the VB. they all slid out rather easily or with the use of pliers to grab them. Should they come out rather easily or should they be a tighter fit than that? They wouldn't wiggle around once inserted back in. However if I'm seeing pressures as low as I am, I would think even a worn out valve body would have SOME pressure especially than 0 in reverse.

Unless I am missing anything to troubleshoot on the valve body...but I think I have done all I can?

I suppose I could put the VB back in and try the Manual 1st pressure readings to see if those are 0 as well.. but would that matter if reverse was 0 anyways...that would mean something in the trans isn't sealing.

[trunnion]

I'd put money on a worn pressure regulator valve bore.
The instructions for the Sonnax repair kit indicate where you can apply vacuum to the valve body to test for leakage on the pressure regulator valve. They also show the test location for the boost regulator on another page, so check that too while you're there.

[jjvincent]

Transmission needs to be taken apart. Stop wasting time in hopes that it's just the valve body. It's not. All of that garbage in the filter tells the tale. When you take it apart you'll find a clutch pack that took a dump. Hopefully you are lucky and it didn't damage the K1/K2 drum. If it did, they were NLA many moons ago and thus you need to find one from a MK4 VW.

#1 problem with the valve bodies are not the solenoids, it's that they get worn out and the reason why Sonax sells an overbore kit for them.

[Abscate]

^

Concur, unfortunately.
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[Michaelryanosier]

Thanks for the vacuum test advice. I took the VB over to a local shop/transmission factory and they vacuum and "dynamically" tested it. Valve Body is fine. So at least I have peace of mind on that. So yup...all hope is lost and it has to come out (I was in denial).

I also learned that the VB on a Eurovan 01P is indeed different than an 01M. Even though 01M is stamped on the underside of the VB, there should be an "E" on the side of the main block which indicates it is for an 01P. The passages in that block are slightly different than the 01M and thus are definitely not swappable as previously mentioned on this post.

The mechanic seemed to think that the clutch plates fried themselves especially he said from the dark/black and thin "watery" nature of the transmission fluid that was residual in the VB, confirming the opinions on this thread.

I then asked his opinion on why my pressure readings were so low in drive and 0 in reverse and if that indicated either the torque converter or pump is bad. He suggested that perhaps only a small portion of the clutch wear material made it through the transmission case into the filter, and the rest is spinning around the transmission and blocking screens protecting the passages within the trans and that could be causing the loss in pressure. He said the torque converter should be ok since the car would go forward.

I asked if when I open the transmission case if it would be apparent that if the pump or the torque converter is bad and he said that the torque converter is a sealed unit and has to be cut open in order to be rebuilt and welded back shut so there wouldn't be any evident visual indication it is bad other than the spindle (I'm forgetting exactly how he explained it) should move forward and out freely. The pump I'll be able to see but it should be good unless it really melted.

What should I be looking for when I open the transmission?

What parts would be recommended to be replaced for sure? Versus which can be inspected and possibly reused?

[Michaelryanosier]

Below are images of the K1 clutch friction pads... In my inexperienced opinion they look fine to me. At least fine enough to function in reverse. Am I correct?

Am I correct in thinking these are what would be responsible for reverse? If so: looks like I have a different problem for my loss of reverse. What else should I be looking for? I suppose I'll have to press apart the other clutches and look inside the pump to see if it is worn. Any ideas? What else should I be looking for as far as no reverse is concerned.

Thanks in advance.

[kourt]

That last picture is priceless.

In my experience, your frictions and steels look fine and do not show signs of significant wear.

kourt

[jjvincent]

Take everything apart. That metal in the filter came from somewhere. As for the clutches, even mine were not worn that much (as I measured them too). It was the one friction plate failed (it cracked) and then it went south. Contrary to what many think, the friction plates really last a long time. It's the stuff that operates them that fails and then it starts a downward trend of things wearing out at an accelerated pace.

Again, find out where al of that metal came from. In the end you'll want to take all of the packs apart. Most likely, you'll have to use 4th over again as the Sonax kit is really for a MK4 VW and 4th is a different pack.

[Stripped66]

[Michaelryanosier]

Upon further inspection, I'm pretty sure that I am looking at the reverse clutches according to this parts diagram

I thought they all looked ok because they are uniformly pretty smooth, but looking closer at the first plate it has much more material on the front side rather than the back:

And the clutch material on the thick side does show some wear (though if all the plates had clutch discs had this much material I would think it would at least function?).

The rest of the clutches are quite thin...I'd say no material at all but indications of where it once was adhered onto the surface of the disc...so perhaps they had just worn down so far that the clearance is too low and the final amount of friction material disintegrated itself when I felt the reverse fail for the final time? The others look like this:

The pump looks fine to me, I would just be looking for grooves worn into the top surface that would allow fluid to pass between the orifices instead of directing it into them? The top surface is flat and smooth.