transmission 3 4 hub: check feel at tranny shifter?

[Vanagon Nut]

Hi all.

For an '88 transaxle 3/4 slider hub.

If the 3/4 slider hub is cracking or broken, with shift linkage disconnected from selector at tranny, when working selector, would I feel a difference shifting into 1 vs 3 ? i.e. more effort required to shift into 3 ? or same for 1 vs 4 ?

Tranny shifts ok in colder weather, gets better when warmed up, has had no shift issues. Clutch is near new, linkage looks ok. 2nd gear "catchs" slightly sometimes. ("normal").

Symptoms:

- Lately, it takes a little more effort to shift into 3 from 2 and between 3 and 4. That "effort" has almost a vague or not so positive feel. Especially for 3. Hard to describe. I also feel a random bit of gear catch shifting into 3. Those symptoms didn't suddenly appear but were noticeable of late so could be "sudden" changes.

- heard squeak in linkage shifting into 3. Lubing linkage made overall shifting much easier, might've slightly improved the above symptoms but they seem to remain

Do these symptoms sound like a failing 3/4 hub?

Neil.
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1981 Westy DIY 15º ABA

1988 West DIY 50º ABA

VE7TBN

[MarkWard]

Generally the 3/4 shift is the easiest to select by hand at the transaxle. The other gears require you to move shift assembly in to then select 1/2 or reverse. The same is true when shifting from the seat.

Forgetting the shift from second to third. How smooth is the shift between 3 and 4? Or 4/3? If you check my photos, there is a picture from my Syncro with a broken 3/4 hub. All the parts were retained in place and no indication the hub was broken. I found it doing something unrelated in the transaxle.

Once it starts flinging the working parts, I would expect it harder to move between 3 and 4 and if the catches have fallen out, grinding on shift would be expected. Nothing to retain and operate the synchronizer rings.
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[Sodo]

Interesting discussion for slider hub diagnostics.

Shifting from 2nd to 3rd involves moving the 3rd gear slider from Neutral to rearward, so it does involve the 3-4 slider moving rearward.

It seems higher ground speeds can throw broken hub parts outward, making it harder to slide?

Does ground speed make a difference in shifting effort?
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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

[Vanagon Nut]

[Vanagon Nut]

[MarkWard]

I don’t have a photo uploaded, but another problem is the mainshaft bearing. It can come loose in the case. The input shaft can move so much 3rd gear idler will grind into the shift shaft.

So you could pull the shift shaft fairly easily, inspect it and look at the slider assembly, but as mentioned in the thread you linked, you won’t see much.

Neil, your a DIY guy. Rather than ship my transmission back and forth across the country, I bought the 3 main tools and did it myself.

You can go to Weddles website and get most of what you need. You can also see a picture of the assembled shift sleeve assemblies. The new 3/4 outer ring is still not available. I used the 1/2 outer ring on a hub I purchased from Gears.

The 091/1 is fairly straightforward to disassemble and reassemble. I made all the other tools I needed. We have a good supply of different OD tubing which helps. You’ll need a press. I used a piece of wood to drive the pinion shaft out. I used the shop bbq to heat the case to install the pinion.
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[Vanagon Nut]

[Ahwahnee]

[Vanagon Nut]

[MarkWard]

You should not have to push the shift lever to the side to select 3/4 on a 4 speed. In neutral at rest, pushing the shift rod straight forward selects 3rd. Pulling straight back selects 4th. If it requires side movement, something is out of adjustment or the internal shift mech is sticking.

I’d rather build transmissions than engines. You can do quite a bit of maintenance on a vanagon transaxle if you are not swapping out the ring and pinion with regular tools.
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[goskiracer]

Miles on transaxle and power plant?

175K was about the mean milage for when the factory "square notched" 3-4 slider would give out, YMMV. And this is not rigorous MTTF analysis, just some numbers I recall reading here on thesamba.

I have only personally opened up three boxes to look at the 3-4 slider, all three were either cracked or completely separated.
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86' Syncro 2.2 Vanistan, WBXhaust, ski-pole shifter for +11hp

[atomatom]

i share your fear of opening the box. i recently confronted it to fix a poorly sealed cover - the only negative thing on my gta rebuild (which leaked since i got it). i was convinced it was going to burst into pieces with springs/etc going everywhere.

i hope your gears are ok.

with a cheap usb borescope, you might be able to take a peek without opening it up.

my 3/4 gave up just after my engine rebuild. i wanted to go camping so i didn't explore the DIY rebuild. when it failed it was making a lot of noise and then it simply refused to move when in 3/4 gears. i limped home (2 km) in second. but to be honest - i never confirmed the failure.

i am just about to put my engine back in the van after a clutch job and i'm not looking forward to getting the shifter linkage together perfectly. so many places to go wrong. i replaced the boot on the shift selector/ball socket thing, and so i unbolted the arm with the ball from the transaxle - now wondering if it is back on the right groove, or if i've screwed it up.
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84 Vanagon Westy, 1.9L, California raised but defected to Canada.

[MarkWard]

I’ve posted this before. I never worry about the spline position. Once you understand how it works, the adjustment is so straightforward and easy, it takes no time to reset it.

With an assistant sitting in the van, have them select the gears while you watch the shift box from below. What you are adjusting is the gap between 3/4 and the reverse lock out plate that locates the 1/2 shift. The manual lists a specific measurement and in the end it’s not that critical.

Once you figure it out, you’ll be thinking it’s so simple
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[atomatom]

[Vanagon Nut]

[Vanagon Nut]

[Vanagon Nut]