TheSamba.com :: View topic - Building a better Vanagon automatic transaxle

Sat Jul 16, 2022 6:47 am

You have pressure from the pump since you still have reverse. Reverse requires the most pressure anyway, so you should be okay..
With the valve body removed, there are ports now exposed that can be used with compressed air, like a rubber tipped blow gun, to see how each clutch pack is moving, or not if that’s the case for testing/function.
There are probably pictures of them in this thread, if not, then elsewhere here on Samba. 3 ports I think.
Sorry for your troubles, it IS frustrating. :cry:

Sat Jul 16, 2022 7:20 am

jlrftype7 wrote: You have pressure from the pump since you still have reverse. Reverse requires the most pressure anyway, so you should be okay..
With the valve body removed, there are ports now exposed that can be used with compressed air, like a rubber tipped blow gun, to see how each clutch pack is moving, or not if that’s the case for testing/function.
There are probably pictures of them in this thread, if not, then elsewhere here on Samba. 3 ports I think.
Sorry for your troubles, it IS frustrating. :cry:

Thank you for the response. I am encouraged that pump is working! I did activate the first reverse brake, I believe that what they are called (large steels and frictions that you can see with the valve body removed) and they seemed to engage properly. I also was able to get the 2nd gear brake band to engage, although it was before the final adjustment I made per the Bently. I did not complete the test in figure 4 on page 38.18 (shame on me!)

Sat Jul 16, 2022 7:44 am

Howdy,

Let's get the tests on Bentley page 38.11 (and also documented here) done and let us know what happens.

kourt

Sat Jul 16, 2022 8:27 am

kourt wrote: Howdy,

Let's get the tests on Bentley page 38.11 (and also documented here) done and let us know what happens.

kourt

Thank you Kourt. Hopefully I can get to them tomorrow. I will video tape them so you all can see/hear what is happening.

Sun Jul 17, 2022 5:29 pm

Ok dropped the pan and this is what I found. Small amount of debris which appears to be fibrous (see picture pictures) I was careful to use old wicking t shirts that were lint free, but who knows. Maybe friction material? it does not feel too gritty.

The link below will take you to the videos of my air test for 1st/reverse, 1st clutch, 3rd gear, second gear brake servo and a video of the linkage moving.

From my observation, 1st/Reverse seems to be acting like it should. 1st gear clutch, I hear a quiet clunk and air escaping. Not sure what that means as I am not following AtlasShrugged's description as to if escaping air is good or bad? 3rd gear, I don't hear a clunk, just escaping air. 2nd gear brake servo is activating although I don't see the band moving. Perhaps it is adjusted too tight? I set it to the torque spec but it did seem tight. If it turns out it is in fact too tight, next time I will test before putting the valve body back on. Take a look at the link to watch the videos and let me know what you think. I certainly appreciate your help and advice! If you need me to re-shoot something, just let me know.

https://drive.google.com/drive/folders/1OGvgfoRSVp_uZtgqf29oJmObiEjHutaf?usp=sharing

Mon Jul 18, 2022 10:58 am

From my experience, if the 2nd brake band is too tight or hung up, you get stuck in a weird situation. Forward movement possible, no reverse possible, and you can't roll the vehicle backward even if you put it into neutral.
At least that's what happened to me with a 2nd trans I bought that had the brake band hung up until I adjusted it correctly after installing it. :roll: :roll:

Mon Jul 18, 2022 2:51 pm

Looking at your videos, all of the compressed air tests seem to be failing. I would plan to remove and reassemble this transmission. I think you can get this fixed--but it's going to take another reassembly. I think you said you replaced all the pistons, correct?

kourt

Mon Jul 18, 2022 4:01 pm

kourt wrote: Looking at your videos, all of the compressed air tests seem to be failing. I would plan to remove and reassemble this transmission. I think you can get this fixed--but it's going to take another reassembly. I think you said you replaced all the pistons, correct?

kourt

Yes I replaced all three pistons.

I added the original video of the first/reverse which I sent to you last week when we were discussing the number of frictions. Can you let me know what you are seeing/hearing different in that video and the one I took yesterday?

Ok I will drop it out again and document with lots of video and pictures.

Tue Jul 19, 2022 4:00 am

From memory, 2nd gear brake band is torqued twice and backed off 2 1/2 turns after final torque. Pg 38.12 Fig 15 some folks have missed that.

A rebuilt trans should be clean for quite a while. That you have shifting problems is not a good sign. It’s possible to mix up the fiber plates between the forward clutch and D R clutch. Subtle differences. Kits used to include extras since the kits covered many versions. You need to measure your assembled clutch packs per the book. Good luck.

Tue Jul 19, 2022 6:05 am

MarkWard wrote: From memory, 2nd gear brake band is torqued twice and backed off 2 1/2 turns after final torque. Pg 38.12 Fig 15 some folks have missed that.

A rebuilt trans should be clean for quite a while. That you have shifting problems is not a good sign. It’s possible to mix up the fiber plates between the forward clutch and D R clutch. Subtle differences. Kits used to include extras since the kits covered many versions. You need to measure your assembled clutch packs per the book. Good luck.

Thank you for the response Mark! Confident I set the brake band to what you state above. With that said, I will double check my Torque wrench is adjusted/tuned correctly, as something seems amiss! I will document what frictions I put in each pack as I disassemble and double check measurements to decide if I did that correctly.

I will post my results, thanks again!

Tue Jul 19, 2022 7:38 am

To clarify, It's inch pounds not foot pounds. Inch pound torque wrench is not very common to have on hand for a lot of folks.

Tue Jul 19, 2022 10:37 pm

Ok so the inner seal of the the forward clutch piston is torn (brand new from Witt) so I assume that is the source of the problem (see pictures below). So I can understand, any ideas how this happens? It seems that the shaft it slips over is pretty smooth. Faulty part, to much pressure some how? The old one does not look too
bad but I will order a new one.
Looks like I probably tightened the 2nd gear brake band to tight. do the indents in the picture mean I should replace the band?

I posted a couple more video of the the different clutch packs engaging now that I have it torn down if anyone want to look and see if the are operating properly.

Also I took a a couple of pictures of the friction and steels, frictions might have some uneven wear. Please give me your thought on if I should replace them?

End play seems to be in spec for forward clutch pack at about .6MM and Direct/reverse clutch is at 1.99 .06mm shy of the 2.05 lower limit, I will double check tomorrow. One of the cir clips is not quite flat, is this a concern?

Wed Jul 20, 2022 5:00 am

Yep..that forward seal is pouched...I cannot tell from the pictures and be sure that seal is installed correctly and not upside down..that seal moves against the spring and if it is upside down then that inside lip will move too far and get cut on the drum. OR, it may be just a bad seal.

You can check you clutch pack on the bench with air pressure. Find the small port (hole) and see how the clutch pack works when the port is pressurized.
If it is moving too far you will see it.

Use Vaseline generously on all the rubber seals and rings when assembled.

Brake bands are not too expensive, or they didn't used to be. If in doubt..replace it.

That bent C clip should not be a problem. One C clip is pretty malleable AIRC

There is a spec for the thickness of the frictions. If they are warped, burnt or thin.. replace them. Remember there are two types with a pattern for location. They are different thicknesses.

Wed Jul 20, 2022 5:52 am

AtlasShrugged wrote: Yep..that forward seal is pouched...I cannot tell from the pictures and be sure that seal is installed correctly and not upside down..that seal moves against the spring and if it is upside down then that inside lip will move too far and get cut on the drum. OR, it may be just a bad seal.

You can check you clutch pack on the bench with air pressure. Find the small port (hole) and see how the clutch pack works when the port is pressurized.
If it is moving too far you will see it.

Use Vaseline generously on all the rubber seals and rings when assembled.

Brake bands are not too expensive, or they didn't used to be. If in doubt..replace it.

That bent C clip should not be a problem. One C clip is pretty malleable AIRC

There is a spec for the thickness of the frictions. If they are warped, burnt or thin.. replace them. Remember there are two types with a pattern for location. They are different thicknesses.

Here are pictures of the seal from different sides. One side is covered in rubber and it was toward the pump. The gold side was up

Wed Jul 20, 2022 6:29 am

You really need to soak everything in ATF prior to assembly. I’m sure there is a special paste for the rubber seals, but we’d use Vaseline to coat the surfaces.

I recall testing the assembled drums with compressed air to manually apply and release them prior to install.

Wed Jul 20, 2022 9:11 am

MarkWard wrote: You really need to soak everything in ATF prior to assembly. I’m sure there is a special paste for the rubber seals, but we’d use Vaseline to coat the surfaces.

I recall testing the assembled drums with compressed air to manually apply and release them prior to install.

Won't make that mistake again! I will definitely be testing everything this time around and making sure everything is lubed.

Can anyone comment on how many frictions to use? Bentley shows 4 for the forward and four for the direct/ reverse and the catalogs show 5 each. I assume go with the Bentley? The first/reverse brake is also confusing in the Bentley as it appears to have two different size steels/frictions. When I originally opened it up it had four steels and four frictions and no wavy washer, again catalogs shows 5 frictions. Maybe 5 for different transmission? Assuming end play is key??
Just don't want to mess this up again!

Wed Jul 20, 2022 10:11 am

Part of assembly is measuring assembled heights. So, if you are stacked too full or to light, it should show up when measuring. There were a lot of versions of that automatic in different applications, so they included extras in some cases. Without knowing, I'd be inclined to follow the manual till you prove it wrong.

Wed Jul 20, 2022 11:26 am

I agree with Mark on this. You want to address each friction stack installation with knowledge of endplay and tolerances. These are usually marked in Bentley.

Be sure you are putting the correct thickness frictions into the correct stacks. You've probably already noticed the frictions are different styles and thicknesses.

kourt

Mon Aug 08, 2022 6:42 pm

Ok update on my transmission. Had it all back together a couple of weeks ago but went on a fire assignment so I am back at it today. Double and triple checked all my backlash and I am in spec. Did the air checks and all seems right with each test. Getting the trans and final drive together was more of a challenge this time but finally got it. So now onto the torque converter bell housing clearance. I am only getting about 2mm Bentley say it should be 10mm . After reading this thread https://www.thesamba.com/vw/forum/viewtopic.php?t=722746 I feel like Mark, Dave and Skills have answered my question about the Bentley maybe just Being wrong or just the fact that others have smaller than 10mm clearances and it is ok. Anyone want to chime in with an opinion? My issues/measurements are exactly as the ones in the thread I referenced.

Mon Aug 08, 2022 9:25 pm

i have yet to build a A/T for myself but I can comment on the TC clearance

if you're measurements are about what i posted in the thread you linked you should be ok

every AT i have ever done would have the TC rub on the bellhousing when it was fully seated. as i recall, this trans did not do that

i would gingerly set the trans to the engine and seat the mounting surface by hand (meaning have the engine and trans kiss each other)

if you can spin the TC you should be fine, in fact you should have a tiny gap as posted in my photo that will disappear when you tighten the TC bolts

basically make sure the TC doesn't bind or you'll break the pump, so don't go all crazy and "send it" by dogging the bellhousing nuts/bolts home until you confirm the TC spins when the engine and trans are mated and flush with each other