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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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 Posted: Sun Jul 20, 2025 5:54 pm Post subject: Removing 091 gear housing |
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I'm finding it hard to find info on this so I figured I'd ask all of you. Is it possible to remove the 091 aircooled 4 speed's intermediate/gear housing without pulling the differential and axle flanges on the other end of the trans?
I'm trying to diagnose my failed 4th gear, but this is my first time inside the Vanagon's trans (I've torn down many other vintage 4 speeds, just not this one!)
The gear shift housing came off easy enough but the gear housing seems to have something still holding it in that I can't seem to find. It'll move a little but not come off. |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 18823
Location: Retired South Florida
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| Posted: Sun Jul 20, 2025 6:44 pm Post subject: Re: Removing 091 gear housing |
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| I’m afraid if you want to access the gear cluster, you will need to disassemble the transaxle. Do you have the factory manual? Wish I had better news. |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Sun Jul 20, 2025 6:47 pm Post subject: Re: Removing 091 gear housing |
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| MarkWard wrote: |
| I’m afraid if you want to access the gear cluster, you will need to disassemble the transaxle. Do you have the factory manual? Wish I had better news. |
Dang, thats what I was hoping to avoid. Thanks Mark! |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 18823
Location: Retired South Florida
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| Posted: Sun Jul 20, 2025 7:12 pm Post subject: Re: Removing 091 gear housing |
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| I haven’t seen it, but I had heard someone had a video. Might be worth searching. |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Sun Jul 20, 2025 7:14 pm Post subject: Re: Removing 091 gear housing |
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| MarkWard wrote: |
| I haven’t seen it, but I had heard someone had a video. Might be worth searching. |
I'll see if I can find that, its been surprisingly hard to find videos on the side shifter 091. I've found for the watterboxer 4 speed, and the bay window nose shifter 091 but nobody tearing down this one. |
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Mile High Puma
Samba Member
Joined: November 11, 2009
Posts: 244
Location: Salida, Colorado
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| Posted: Sun Jul 20, 2025 8:13 pm Post subject: Re: Removing 091 gear housing |
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Should be the same for a water boxer 4 speed. There are some things you need to read up on before disassembly. You will need to remove the diff to get access to the pinion retaining nut. You should mark the bearing adjusters before removing them which takes a special tool. You should also heat the case around the pinion before removing it which also takes a special tool.
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1990 Westfalia Syncro |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Sun Jul 20, 2025 8:24 pm Post subject: Re: Removing 091 gear housing |
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| Mile High Puma wrote: |
| Should be the same for a water boxer 4 speed. There are some things you need to read up on before disassembly. You will need to remove the diff to get access to the pinion retaining nut. You should mark the bearing adjusters before removing them which takes a special tool. You should also heat the case around the pinion before removing it which also takes a special tool. |
I saw that the waterboxer 4 speed had an internal shifter shaft that had to be pulled that mine clearly does not so I was questioning how close the rest of the process was. I know they're very similar for the most part, but I've never seen inside either of them...
I'm used to rebuilding 4 speeds for vintage V8 cars. Ones with proper tailshafts on them  |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 52432
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| Posted: Sun Jul 20, 2025 9:48 pm Post subject: Re: Removing 091 gear housing |
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| GoEverywhere wrote: |
| Mile High Puma wrote: |
| Should be the same for a water boxer 4 speed. There are some things you need to read up on before disassembly. You will need to remove the diff to get access to the pinion retaining nut. You should mark the bearing adjusters before removing them which takes a special tool. You should also heat the case around the pinion before removing it which also takes a special tool. |
I saw that the waterboxer 4 speed had an internal shifter shaft that had to be pulled that mine clearly does not so I was questioning how close the rest of the process was. I know they're very similar for the most part, but I've never seen inside either of them...
I'm used to rebuilding 4 speeds for vintage V8 cars. Ones with proper tailshafts on them |
The nose cone of the Vanagon 091 removes the same as the bay window 091 if I am not mistaken. |
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67rustavenger
Samba Member
Joined: February 24, 2015
Posts: 11207
Location: Oregon
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| Posted: Sun Jul 20, 2025 11:42 pm Post subject: Re: Removing 091 gear housing |
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| GoEverywhere wrote: |
| Mile High Puma wrote: |
| Should be the same for a water boxer 4 speed. There are some things you need to read up on before disassembly. You will need to remove the diff to get access to the pinion retaining nut. You should mark the bearing adjusters before removing them which takes a special tool. You should also heat the case around the pinion before removing it which also takes a special tool. |
I saw that the waterboxer 4 speed had an internal shifter shaft that had to be pulled that mine clearly does not so I was questioning how close the rest of the process was. I know they're very similar for the most part, but I've never seen inside either of them...
I'm used to rebuilding 4 speeds for vintage V8 cars. Ones with proper tailshafts on them |
Bro, There's no real comparison between a inline four speed trans and a VW transaxle.
I too used to rebuild Saginaw 3-4 speeds, simple work. A transaxle, not in my bellhouse.
If you throw in the towel, Hit up myself or Xevin for a shop in Damascus that does high quality transaxle work.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!
2003 Astrovan? GFYS again, Xevin! 
Don't let your bad ideas remain, ideas! |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 18823
Location: Retired South Florida
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| Posted: Mon Jul 21, 2025 6:13 am Post subject: Re: Removing 091 gear housing |
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If you are familiar with manual transmissions and differentials, there is no reason not to attempt this. The hold up is a couple special tools you really must have. The socket for undoing the large pinion nut a must. Available for purchase is the side ring tool that support the differential bearings. Some have fabricated this.
Ideally you’d have a spare transaxle on hand. For the cost of shipping cross country twice, you can purchase the tools you will need. I use Weddle and GT for tools and hard parts. If the goal is to only address 4th gear, you can bypass quite a few tasks.
I’m speaking from experience. Because I didn’t have the special tools, I paid one of the reputable builders to build mine. It lasted about 60k. Now that I have the tools, even if it wears out again, I can build it myself. Good luck with your decision. |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Mon Jul 21, 2025 8:16 am Post subject: Re: Removing 091 gear housing |
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| 67rustavenger wrote: |
| GoEverywhere wrote: |
| Mile High Puma wrote: |
| Should be the same for a water boxer 4 speed. There are some things you need to read up on before disassembly. You will need to remove the diff to get access to the pinion retaining nut. You should mark the bearing adjusters before removing them which takes a special tool. You should also heat the case around the pinion before removing it which also takes a special tool. |
I saw that the waterboxer 4 speed had an internal shifter shaft that had to be pulled that mine clearly does not so I was questioning how close the rest of the process was. I know they're very similar for the most part, but I've never seen inside either of them...
I'm used to rebuilding 4 speeds for vintage V8 cars. Ones with proper tailshafts on them |
Bro, There's no real comparison between a inline four speed trans and a VW transaxle.
I too used to rebuild Saginaw 3-4 speeds, simple work. A transaxle, not in my bellhouse.
If you throw in the towel, Hit up myself or Xevin for a shop in Damascus that does high quality transaxle work. |
Yeah, I'm starting to realize that. Not that I don't think I could do it, but they're a fair bit more complicated than your usual standard 4 speed!
I'm actually not likely going to rebuild the trans, I've got a reversed Subaru trans that's going in. I'd just like to know what I broke. I was going to pull the intermediate housing off to see how bad it was... After all its not every day you get to see what happens when you pair a 67HP VW transmission with a 500+ HP turbo Subie |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Mon Jul 21, 2025 8:17 am Post subject: Re: Removing 091 gear housing |
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| MarkWard wrote: |
If you are familiar with manual transmissions and differentials, there is no reason not to attempt this. The hold up is a couple special tools you really must have. The socket for undoing the large pinion nut a must. Available for purchase is the side ring tool that support the differential bearings. Some have fabricated this.
Ideally you’d have a spare transaxle on hand. For the cost of shipping cross country twice, you can purchase the tools you will need. I use Weddle and GT for tools and hard parts. If the goal is to only address 4th gear, you can bypass quite a few tasks.
I’m speaking from experience. Because I didn’t have the special tools, I paid one of the reputable builders to build mine. It lasted about 60k. Now that I have the tools, even if it wears out again, I can build it myself. Good luck with your decision. |
If its going to take ordering specialized tools I may not bother... I don't actually NEED this trans, I just wanted to know what I broke. Though given how it was acting I'm reasonably certain I stripped the teeth from 4th.
It would have been nice to fix it and move it on to someone else who needs a lower performance transmission than I do, but I'm guessing I'll likely just move it on as a core and let someone else rebuild it before I go buying specialized tools. |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 18823
Location: Retired South Florida
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| Posted: Mon Jul 21, 2025 8:25 am Post subject: Re: Removing 091 gear housing |
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| You might be able to see 4th gear through the fill port with a scope. If you’re going to do the Subaru transaxle, might as well sell the VW one on. Someone could use it. 500 hp plus? Good luck keeping a Subaru reverse transaxle together. I don’t think you need to autopsy the VW one if 4th was seeing that type of load. Weight and aero drag are your enemy. A better solution might be a G50 Porsche transaxle. |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Mon Jul 21, 2025 8:28 am Post subject: Re: Removing 091 gear housing |
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| MarkWard wrote: |
| You might be able to see 4th gear through the fill port with a scope. If you’re going to do the Subaru transaxle, might as well sell the VW one on. Someone could use it. 500 hp plus? Good luck keeping a Subaru reverse transaxle together. I don’t think you need to autopsy the VW one if 4th was seeing that type of load. Weight and aero drag are your enemy. A better solution might be a G50 Porsche transaxle. |
Thats a very good idea, I do have a scope I could put down there. Easier than tearing it down for sure.
The trans I have is built for power, its a Japanese market STi trans that was setup to run behind a very similar motor in a friend's Subie powered Porsche 912. It AUGHT to be ok. Probably
I actually looked at the G50's but couldn't find one that was actually functional for anything less than about 12k. Those things have SKYROCKETED in price since I first started to pay attention to them. |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 18823
Location: Retired South Florida
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| Posted: Mon Jul 21, 2025 8:39 am Post subject: Re: Removing 091 gear housing |
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| A 912 is quite a bit lighter and aero than your bread box. 500 boosted hp and torque would be a lot for any gearing. Weddle makes some racing transaxles that could likely handle the abuse being handed out. I really don’t know. If you look in my photos are pictures of my worn 4th and syncro ring. The loads of my messily 1.9 TDI were forcing the dog clips up onto the sides of the brass ring and I operate like I have an egg under my foot. You’ll probably have multiple opportunities to try different transaxles. No free ride I’m aware of. |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Mon Jul 21, 2025 8:45 am Post subject: Re: Removing 091 gear housing |
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| MarkWard wrote: |
| A 912 is quite a bit lighter and aero than your bread box. 500 boosted hp and torque would be a lot for any gearing. Weddle makes some racing transaxles that could likely handle the abuse being handed out. I really don’t know. If you look in my photos are pictures of my worn 4th and syncro ring. The loads of my messily 1.9 TDI were forcing the dog clips up onto the sides of the brass ring and I operate like I have an egg under my foot. You’ll probably have multiple opportunities to try different transaxles. No free ride I’m aware of. |
Thats fair, I'm putting a lot of power into a heavy un-aerodynamic brick. I'm asking a lot from any trans. I guess only time will tell if this solution is the one that does it or if I break another one later and have to go some other route...
I DO know that people are building 1000HP WRXs with variants of this same transmission without doing too much to them so I'm hopeful. If not I'll probably end up talking to Weddle/Mendeola. But MAN those boxes are some cash!
I suppose at the end of the day I could just turn the boost down and try and enjoy it at a lower power level... I'm just really not very good at that. |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 18823
Location: Retired South Florida
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| Posted: Mon Jul 21, 2025 8:53 am Post subject: Re: Removing 091 gear housing |
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Build a Racecar. That’s what I did. Our van needs reliability for me to relax when traveling. I have reasonable torque and hp but rarely use them and when I do, I’m aware.
Plus, it’s always the weakest link. I’m surprised your clutch is able to handle that power. Next the CVs and then the splines in the rear hubs. It’s probably a hoot to drive yours. I had the opportunity to drive a Vanagon camper with a Porsche 911 3.0 with a 915 5 speed. That was a hoot. It was a bmw sedan slayer. A wolf in sheep’s clothing. |
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Xevin 
Samba Member
Joined: January 08, 2014
Posts: 8707
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| Posted: Mon Jul 21, 2025 8:56 am Post subject: Re: Removing 091 gear housing |
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| GoEverywhere wrote: |
| I suppose at the end of the day I could just turn the boost down and try and enjoy it at a lower power level... I'm just really not very good at that. |
 
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Keep on Busin'
| 67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
| Clatter wrote: |
| Damn that Xevin... |
| skills@eurocarsplus wrote: |
| I respect Xevin and he's a turd |
| SGKent wrote: |
My God! Xevin and I 100% agree  |
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GoEverywhere
Samba Member
Joined: December 13, 2020
Posts: 927
Location: Portland, OR
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| Posted: Mon Jul 21, 2025 9:40 am Post subject: Re: Removing 091 gear housing |
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| MarkWard wrote: |
Build a Racecar. That’s what I did. Our van needs reliability for me to relax when traveling. I have reasonable torque and hp but rarely use them and when I do, I’m aware.
Plus, it’s always the weakest link. I’m surprised your clutch is able to handle that power. Next the CVs and then the splines in the rear hubs. It’s probably a hoot to drive yours. I had the opportunity to drive a Vanagon camper with a Porsche 911 3.0 with a 915 5 speed. That was a hoot. It was a bmw sedan slayer. A wolf in sheep’s clothing. |
Ohh I've got a racecar too. I've got a 1200HP twin turbo 426ci 1966 Plymouth Satellite Clearly I have a problem.
I've got a Kennedy Stage 3 clutch in mine currently. The stock clutch would never hold. I've broken 2 930 CVs already, and twisted one axle.
Its an absolute BLAST to drive. I call it my sleeper sleeper... Because its a camper and all I outrun most anything in a straight line. The looks on Corvette owners faces when they loose at the light to a Vanagon is worth every single part I've broken
And it does ok-ish in corners too. I've got a lot of suspension work done to it, but at the end of the day its a big heavy brick. Only so much I can do handling wise. |
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67rustavenger
Samba Member
Joined: February 24, 2015
Posts: 11207
Location: Oregon
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| Posted: Mon Jul 21, 2025 10:14 am Post subject: Re: Removing 091 gear housing |
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Ya know, if your subi-gears box takes a dirt nap. You can always contact Marks Sand Trans in Forest Groove for a stout transaxle build.
Mark does LS Swapped transaxles for fun and $$$$$$.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!
2003 Astrovan? GFYS again, Xevin!
Don't let your bad ideas remain, ideas! |
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