xflyer
Samba Member
Joined: June 15, 2006
Posts: 314
Location: SOCAL
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 Posted: Sun Jun 17, 2018 9:19 am Post subject: Re: Auto Tranny - intermittent 2nd to 3rd upshift - Rebuild |
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I know this is an old thread. (there should be an icon or abbreviation for that).
I'll put in my 2 cents from more than 25 years of work done on VW auto transaxles.
First about the shifting problem, 2nd to 3rd, or any other full auto Vanagon shift problem, such as a lag time before a gear will engage when shifted out of P or N often worse when cold. Make sure all adjustments are correct. The shift cable from the lever to the trans has to work correctly. Make sure none of the parts, cable, lever (the one you move when driving), and cable housing are not damaged, bent, etc. The cable/rod is adjustable at the front, page 37.3 in Bentley. If that is a little off the shifter may look like it's in D, but it's a little bit towards 2.
Check the accelerator/throttle rod from the trans lever to the throttle body. Usually this only involves getting full throttle on the engine and the downshift/kickdown on the trans. However I've seen plenty of vans, Bay window and Vanagon, where this is off a little and causes all sorts of weird shifting problems. Yes I know, most of the Bay window automatics don't have the rod so check the vacuum modulator.
Most common though is that the trans is just worn out. The photos on this thread and a good read of the Bentley will show that there are many seals, O-rings and clutches in the auto trans. These should all be replaced along with all the bushings, and thrust washers whether they are metal or plastic.
You can get rebuild kits from suppliers with all this stuff for under $200. Also get some TransGel or similar auto trans assembly lube. This will help hold those thrust washers in place and make getting lip seals and O-rings in without damage.
Those seals and O-rings will get hard over time and wear a little. A tiny amount of leakage makes the trans shift wrong or not at all.
Similar with the clutches. The repair books give wear limits to check on these. Don't waste your time. If the trans is 10 years old or has more than 80-100K miles, replace all the friction and steel plates with new. All the parts might be within spec, but still not work correctly.
And a few words of caution to those contemplating working on a full auto trans for the first time.
Make sure that you have the time and space to do this. Recheck your moves with the Bentley at each step. Cleanliness is very important. A tiny piece of shop towel or dirt in the wrong place will mean you will have to take it back out and start over. You need an area to spread out all the parts as was done in this thread without getting in anybody's way. I have seen a tech clean and lay out a whole collection of parts for assembly only to have someone walk by and without looking grab a shop towel out from under them to wipe their hands, scattering the parts everywhere. Also unless there is a lot of junk/wear particles/debris inside I would suggest to leave the valve body assembled. There are many small parts, springs, plungers, etc inside. Even though they may look the same they are usually different in some way. If they get switched around the trans may have worse shifting than when you started. Clean it off from the outside and bolt it back on. If you have to you can remove it without taking the trans out. These transmissions are all mechanical/hydraulic pressure shifted. I have seen weird shifting problems cured by switching the valve body from another trans of the same type. That was when there was no detectable wear or broken parts in the valve body.
Not trying to throw anyone off here. This same basic trans, with different final drive units, was used in many different VW, Audi, and other vehicles from 1968 through the 1990s.
Thousands of them get rebuilt every year and most of those actually work!
So if you have some good mechanical skills, time and a lot of patience you can do it too.
And don't get into a big tizzy over the fluids. I was at the FLAPS recently and after reading some questions about that on threads here, I looked at a bottle of the latest ATF Dexron/Mercon VI. It had in the description that it was good for anything that needed Dexron V, IV, III, II, and a bunch of other specs and part numbers. Similar with the final drive (diff/ring and pinion) lube, most any 90 GL-5/MIL2105B gear oil will be fine. Also 75W-90, 80W-90, 80W-85-90 will also be fine. The "W" means a "winter" grade, which means it will not thicken as much when temps get below 25F (-5C). Obviously this is better in areas that get those temps.
And don't get me started on the "The GL-5 gear oil will ruin your synchronizers". Never saw that happen in over 30 years of overhauling and repairing VW and Porsche manual shift transaxles.
If I read that again I'll have to wrap my head in aluminum foil and dance under the full moon to ward off the evil synchronizer destroyers.
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1989 Campmobile, 1984 7 passenger beater Vanagon
Both with cool A/C |
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autotech_ken
Samba Member
Joined: March 31, 2011
Posts: 5
Location: North Carolina
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| Posted: Mon Jul 28, 2025 12:55 pm Post subject: Auto Tranny engagement 3 was okay now not |
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This is an old post but we are experiencing a no 3rd gear engagement on our 86 auto trans in the Vanagon. The PO rebuilt the trans using a std rebuild kit the old basket clutch plates were in a box and were totally worn . He seemed pretty sharp but in same breath we had problems with the trans slipping in 2-3rd . We have had the valve body down twice now it all looks good however pressures were off we questioned if the two similar pressure adjusters may have been swapped and he confirmed maybe so . Swapping them cleaned up the slipping, and were able to get 3rd.
1st initial test drive all seemed good at highway speeds - however to get 3rd required a pedal off to engage 3rd and there is no kick down however the motor side adjuster is set correct for kick-down. The Front side adjustment confirms the spring loaded detent engages in the detent positions properly.
After the 15 minute highway test we pulled over and stopped and let it sit a few minutes as started smelling trans fluid but no dripping maybe a small leak at tans cooler hose connection. On the drive home no 3rd gear, we had to nurse it on back roads running only in 2nd. We pulled valve body again all looked clean put it back in. backed off 2nd gear brake band still no 3rd . maybe brake band needed to be turned in? Post in this thread suggested turn it out 2 turns.
At this point we may end up taking the trans out and going through the whole thing. One interesting point was the valve body didn't quite match the Bentley it maps to an 090 trans but the "housing apply valve 1st -Rev" was considerably smaller than shown in the Bentley for the 090 010 trans images.? Any thoughts before we pull the trans? Thanks Ken in NC |
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