91 Syncro - Stuck in 3rd - Tranny still works other gears

[SyncroScout]

*note I have read the other post here on Samba on the subject.

After a gear oil change (Royal Purple 75w-90), it took 3,5 quarts. -

I recently went cross country with my newly purchased 1991 Syncro with approx 135k miles

I thought the Transmissions after 1990 had the updated 3rd - 4th gear???

As well as hardened nitrided gears??

Came home and she was driving like a champ.

All of the sudden I found the transmission completely stuck in 3rd gear!

It had done a couple of weird things beforehand, it would clunk going into 1st with the clutch 100% fully depressed.

Also it felt like the gear shifter was stuck a couple of times getting out of reverse out of the "lower plane"

Any truth to the later 19990-1992 trannies being immune to the 3/4 slider issue?

Is there anything else that could cause the stuck in 3rd scenario?

The van had fresh shift kit up from , bushings and GO Westy billet shift linkage

Im both bummed and happy that its getting a rebuild at Rancho, the rear locker has been seized since I bought it so I gotta try and look at the brightside.

[SyncroScout]

oh ya, tranny has not been pulled out yet....

So there's still time to investigate other possible causes.

[SyncroScout]

Also its not the clutch slave cylinder, 1st-2nd and Reverse work fine.

[Sodo]

It was about 1989.5 that VW changed to the “nitrided slider “ with the slightly rounded failure corners.

They still break. Failure is not as “certain” as with the sharp corners slider. That’s the hard part about engineering a “lifetime limiter” part. The square corners design is certain to fail, the question is “when”? Certainly sooner if the van is driven by a lugger.

Rounding the corners increases the fatigue life substantially. Then VW gives it a mumbo-jumbo name like “nitrided” hoping you like their science-word (nitrided) which hides the intent and makes it look like they improved quality, adding an emerging a surface-treatment technology that was previously unavailable.
Constantly improving!!

But mainly its to obscure the fully intentional “square-corners failure point”. Square corners is not a gearbox design “oopsy”.
A tool was specified on the drawing - to cut that square corner.

Possibly your van had a “lugging driver”, where your parts accumulated many more lugs (cyclical/fatigue loading, pounding) during its relatively young lifetime.
And your mainshaft bearing would be well-pounded as well. Once it gets “loose” it causes all kinds of trouble. And the 4th gear idler needle getting loose is bad too.
Don’t lug.

A big hairdo on the magnet is dust coming from the races of your bearings. And eventually “gravel” from the substrate of your bearing races (longer particles that look stringy on the magnet). Those are like the gravel that you see on the road near a chuckhole. Some get caught by the magnet for you to look at (if you look). The other 99% are swirling around with your lubricant.

When you see the longer stringy hairdo, start saving $$$. Theres not many miles left. Of course its best to stop driving it because you’re grinding up many other parts, significantly reducing the runtime of your next rebuild.

Its ideal the get that stuff out of your lubricant early & often.

A commod advice given is to wait for chunks. Thats poor advice.

And its likely that your van still had the original oil at 135,000. Lots of people change oil after they “hear sounds”. Which of course is too late.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[SyncroScout]

After this rebuild at Rancho, the tranny will get babied 100%

I've read your other threads Sodo - thatks for sharing those hard experiences.

[16CVs]

Mike at Rancho is a great guy. He did 2 Syncro transaxles for me last year. Those guys know lots of tricks. Ask him about bearing updates and some little extras they do.
One nice thing about them is that they do not use a lot of Weddle parts which I've heard mixed reviews from.
Pull the transaxle and pull the bell housing off and let it drain over night in a pan. Stuff some rags into the housing and put the bell housing back on and strap it to a half pallet. Buy some cheap cargo straps. Once mounted Rancho can do a freight pickup from their shipper and just add it to your bill.
Get ready to spend 5K, you can hope for less but it rarely is.

Stacy
_________________
1987 Syncro Westfalia Triple knob (bastard)
1989 Syncro Tristar Triple knob "Swedish"
2013 Jetta Hybrid a true "Zwitter"
Samba member # 14980
Call anytime number 650 722 4914 .
Keep Your van running and upkept tastefully for the love of the hobby.
Don't let your van end up in an "abortions" thread.

[Syncro Jael]

I am sorry to hear this, spend the money to put the best parts available in there while a rebuilder has it.

It is expensive but I did "Paul's" billet gear carrier, new gun drilled mainshaft, new ring and pinion, all 4 new gear sets, new low range gear, and "Sodo's" kit to oil the mainshaft. I already have the bearing retainer plate, and oiling plates. This transaxle is now sitting on the shelf in the shop hopefully for a few years.

From experience adding a cooling and filtering system really makes a huge difference. Well worth the cost for parts and installation.

My latest rebuild now has over 8K miles on it and is perfectly quiet, shifting smoothly, and I checked the filters and magnets last night. Minimal swarf.

Cheers,
Ron

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1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[MarkWard]

Mine shifted fine in all the gears. Was inside for an unrelated issue and found this.

This was out of an 87 syncro tin top with a possible 170K miles on it.
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☮️

[SyncroScout]

OK!

Tranny was rebuilt by Mike at Rancho.

I am very happy with the quality of the rebuild!

Only comment is that the oil they gave me LPT 85w-110 convetional gear oil caused VERY hard shifting and a loss of at least 3-4 MPG.

I ran it for about 1000 miles then dumped it and replaced with Royal Purple 75w-90 and got butter smooth shifting and all my mileage back.

[Sodo]

[SyncroScout]

Thanks for that info Sodo

When I changed the fluid there was almost zero swarf and just some clumps of Moly from that thick molasses like oil.

I seriously lost the mpg!

...and then gained it back

RP is one of the best gear oils out there.

[tencentlife]