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kourt Samba Member
Joined: August 13, 2013 Posts: 1937 Location: Austin, TX
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Posted: Sun Jan 11, 2015 11:36 am Post subject: Building a better Vanagon automatic transaxle |
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Greetings Vanagon enthusiasts.
In my time as a Vanagon owner and Samba participant I note the great number of threads detailing manual transaxle builds but relatively fewer threads dealing with the Vanagon automatic transaxle.
I should note that my use of the word "transaxle" is deliberate, in that my interest is in both the transmission and differential. This scope does not include CV joints or axles--just the transaxle, torque converter, related fluids, and mounts.
I would like to document my approach to learning about this transaxle and improving it to make it even more reliable than it already is.
That last sentence echoes my current understanding of the automatic transaxle through Samba searches and posts--that the Vanagon 090 transmission is reputed to be very reliable and very maintainable by an amateur mechanic such as I am.
I have a great deal of interest and enthusiasm for this transaxle. Aside from a slight efficiency tax (and driving preferences aside), I think the automatic transaxle is underrated in terms of its performance, maintainability, and adaptability.
My 1991 Westfalia camper has a Bostig engine and a previously rebuilt transmission. I live in Texas and the summers are incredibly hot. It carries my heavy van largely without complaint, but I hope to apply the following improvements over the next few months, and document them in this thread:
1. transmission fluid filtration, cooling, and temperature measurement;
2. Audi 5000 turbo internals upgrade (planetary gears, clutches, bushings);
3. 3.27 ring & pinion;
4. Peloquins LSD;
5. shaved governor and/or throttle cable adjustments to influence shift points;
6. improved transmission mount bushing material;
7. scrutiny of ATF and gear oil choices.
I invite everyone to contribute what they can and add references to this thread, as I feel the Samba's Vanagon community would greatly benefit from an improved reference for the care, feeding, and improvement of the Vanagon automatic transaxle.
I will say up front that I am by no means a transmission expert--rather, I am learning as I go in this process. Please do not interpret my decisions as professional advice or expert opinion.
Stay tuned.
kourt
Last edited by kourt on Sun Jan 11, 2015 12:14 pm; edited 1 time in total |
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IdahoDoug Samba Member
Joined: June 12, 2010 Posts: 10248 Location: N. Idaho
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Posted: Sun Jan 11, 2015 11:48 am Post subject: |
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Subscribed. I bought a used auto trans with the intention of doing exactly as you describe. There are a lot of very smart folks here regarding the objective you seek on the auto and I have read some great threads on it here already. I urge you to also read them if you have not already.
I hope to do mine on the bench over the next year or so at my leisure, then just pop it into the Van with zero downtime. Thanks in advance to you and the other experienced auto trans guys. Whenever I've asked auto questions, I've gotten some really, really great PMs from people telling me what to do.
Cool, now I can sit back and do other things to my van while you do the heavy lifting on consolidating all the smart people's auto knowledge!!! Heh.. _________________ 1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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kourt Samba Member
Joined: August 13, 2013 Posts: 1937 Location: Austin, TX
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Posted: Sun Jan 11, 2015 12:04 pm Post subject: |
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Let's begin with step 1: transmission fluid filtration, cooling, and temperature measurement.
My transaxle presently has a GoWesty cooler:
http://www.gowesty.com/ec_view_details.php?id=4481&category_id=&category_parent_id=
This cooler is a good product in its design, function, and use of space under the van. The oblong shaped cooler occupies an otherwise unused space in the central undercarriage just forward of the rear floorpan bulkheads. The kit comes with a Derale thermostat that opens fully at 180 degrees F and sufficient tubing to make the install easy.
Others have used the FAS cooler:
http://www.foreignautosupply.com/parts-accessories/1-automatic-transmission-heat-sink/#.VLLKG8ZmKYQ
And still others have used the Smallcar cooler:
http://www.smallcar.com/index.php?dispatch=products.view&product_id=29877
During a recent trip to Big Bend National Park in far west Texas over Labor Day weekend, during 100 degree days, we gained a great deal of elevation in the van in a short distance. The GW cooler failed to keep the transmission fluid cool enough for efficient torque converter function--the measured temperature on the transmission case was around 250 degrees F, and there was slippage in the torque converter.
This, and the future desire for a 3.27 R&P (which encourages more heat generation and the need to reject that heat) means I need to find a more robust solution for cooling the Vanagon transaxle.
My present approach is to use a combination of Derale fan driven cooler and remote ATF filter with temperature sender port:
http://derale.com/products/fluid-coolers/universal...pan-detail
http://derale.com/products/filtration/transmission...ead-detail
I'm coupling these with the existing Derale thermostat from the GW cooler (which can be bought separately as liked below):
http://derale.com/products/fluid-coolers/thermosta...kit-detail
Plus an inline fluid thermostat and fan wiring relay to control the fan:
http://derale.com/products/fluid-coolers/thermosta...fan-detail
http://derale.com/products/electric-fans/universal...ler-detail
Summit Racing provides the rest... fittings to convert the thermostat to AN-6 and all the AN-6 fittings and hose:
http://www.summitracing.com/parts/SUM-220648N
http://www.summitracing.com/parts/SUM-230606
http://www.summitracing.com/parts/SUM-220687N
http://www.summitracing.com/parts/AER-FBM3484
Also, I'm vain and like VDO gauges and senders (though the Derale filter kit comes with good ones, I'm going with VDO):
http://www.summitracing.com/parts/VDO-310-111
http://www.summitracing.com/parts/VDO-323905
I should note that the VDO sender is a direct fit in the Derale ATF filter housing.
If you haven't converted the ATF cooler outputs on your transmission to AN-6, you'll need to do that with fittings--but I am not sure what size is coming out of the transmission, so I'll leave that information to others (I'm using the fittings supplied with the GW cooler).
Here's some photos of the goods and where I proposed to install them:
The fan and filter will be installed on the passenger side underfloor, behind the forward jack point. The filter will fit nicely in the narrowed space near the jack point, and the fan will fit farther aft. I have a Propex heater in that space as well, so this fills up the rest of that area.
I show the fan and how far it hangs down below the rocker panel channel--not too bad. The Derale fans are designed to mount to a solid and flat surface, and included a stout aluminum housing that is bushed to reduce transmission of fan vibration.
This is just the fitting stage. When the weather clears up later this week I will repost with the installation phase, including AN hose fabrication. Summit has some great videos online showing how to build AN hoses:
https://www.youtube.com/watch?v=PeeflgGlenY
Stay tuned for more,
kourt |
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kourt Samba Member
Joined: August 13, 2013 Posts: 1937 Location: Austin, TX
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Posted: Sun Jan 11, 2015 12:53 pm Post subject: |
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Have you ever wondered what ATF and coolant intermixing looks like? Most describe it as a strawberry milkshake, or strawberry milk.
For reference, here are some shots of intermixed ATF and coolant. One shows the milkshake pooling at the bottom of a black plastic bag. The other shows intermix on the housing of a transmission following separation from the differential.
kourt |
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kourt Samba Member
Joined: August 13, 2013 Posts: 1937 Location: Austin, TX
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Posted: Sun Jan 11, 2015 12:56 pm Post subject: |
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Here's a preview of coming attractions: a standard Vanagon automatic transaxle on the left, plus an early Audi 5000 turbo transmission on the right, plus a spare Vanagon oil pan and dipstick. The Audi transmission internals will be rebuilt and moved to the Vanagon transmission housing.
kourt |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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tristessa Samba Member
Joined: April 07, 2004 Posts: 3992 Location: Portland, OR
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Posted: Sun Jan 11, 2015 1:34 pm Post subject: |
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djkeev wrote: |
Curious, what is the draw to the Audi Transaxle?
More robust?
If so how? |
Four planetary gears vs. three in the Vanagon, and IIRC more plates in the clutch packs. |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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ThankYouJerry Samba Member
Joined: September 01, 2012 Posts: 2271 Location: Shakedown Street
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Posted: Sun Jan 11, 2015 1:40 pm Post subject: |
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tristessa wrote: |
djkeev wrote: |
Curious, what is the draw to the Audi Transaxle?
More robust?
If so how? |
Four planetary gears vs. three in the Vanagon, and IIRC more plates in the clutch packs. |
Plus bronze bushings instead of plastic. _________________ 1990 Multivan - "Ohana"
1.8T, Auto w/3.27 R&P + Peloquin TBD |
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TequilaSunSet Samba Member
Joined: May 30, 2012 Posts: 2109 Location: Philippines
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Posted: Sun Jan 11, 2015 1:44 pm Post subject: |
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Well fudgy puck... throwing down crack in front of an addict just isn't right...
*I must resist*I must resist*I must resist*I must resist _________________ Don't harsh my mellow...
1985 Hightower Vanagon 1.8T- Gone
1972 Panel Bus- Gone
1967 Bug- Gone
1964 Euro Sunroof Bug- Gone
1969/72/63 Sunroof Bug- Gone
1975 Brazilian Bug in the Philippines 🇵🇭- New to me |
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Jake de Villiers Samba Member
Joined: October 24, 2007 Posts: 5911 Location: Tsawwassen, BC
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Posted: Sun Jan 11, 2015 2:16 pm Post subject: |
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djkeev wrote: |
A Vanagon Weekender is said to weigh 5160 lbs. |
Whoever said that is wrong. My Vanagon Weekender weighs ~4000 lbs. Its usually around 4500-4800 lbs all loaded for a weekend at a bluegrass festival - instruments, food & drink... _________________ '84 Vanagon GL 1.9 WBX
'86 Westy Weekender Poptop/2.5 Subaru/5 Speed Posi/Audi Front Brakes/16 x 7 Mercedes Wheels - answers to 'Dixie'
@jakedevilliersmusic1
http://sites.google.com/site/subyjake/mydixiedarlin%27
www.crescentbeachguitar.com
www.thebassspa.com |
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HoustonPhotog Samba Member
Joined: February 20, 2013 Posts: 1514 Location: Houston, TX
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IdahoDoug Samba Member
Joined: June 12, 2010 Posts: 10248 Location: N. Idaho
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Posted: Sun Jan 11, 2015 2:48 pm Post subject: |
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Agree with Jake. An Audi 5000 Turbo Wagon using this trans weighs 3500lbs empty. It holds 7 passengers I think, so its max GVWR would be close to the Vanagon's 7 passenger GVWR as well though certainly less than the full boat Westy. With a ton more power, its auto trans internals would be expected to be beefier. _________________ 1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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IdahoDoug Samba Member
Joined: June 12, 2010 Posts: 10248 Location: N. Idaho
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Posted: Sun Jan 11, 2015 3:04 pm Post subject: |
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You probably know this, but that's a max allowed weight for that model of Vanagon, not the weight it is hauling around daily. Lop about 1500lbs off that figure for what is known as the curb weight - the empty weight. Though some of the weights people post on their daily driver vans are pretty close!! Heh.
So the Audi 5000 and Vanagon are much closer in weight. _________________ 1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Sun Jan 11, 2015 3:21 pm Post subject: |
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I usually think about it in terms of input torque that the tranny is designed to handle (but that is for a manual trans. on sports cars).....
Does "Four planetary gears" vs. 3 mean you have an additional forward speed? |
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hdenter Samba Member
Joined: October 14, 2008 Posts: 2753 Location: San Luis Obispo, CA
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Posted: Sun Jan 11, 2015 3:25 pm Post subject: |
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You can bicker all you want about which weighs more, but at the end of the day the Audi trans is better made.
Those of us who hate auto transmissions would conceed that the auto trans is reliable. What would get me a little more excited is someone finding a swap with a 4spd auto. Maybe there is a subbie auto that could be fitted with one of the new reversed ring gears.
Good luck though, sounds like you are on the right path.
Hans _________________ '79 triple white convertible bug
'84 sunroof vanagon
'85 weekender |
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boof1306 Samba Member
Joined: July 10, 2010 Posts: 304 Location: MELBOURNE AUSTRALIA
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Posted: Sun Jan 11, 2015 3:32 pm Post subject: |
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Its all about gear contact area, more contact area more strength. ie 4 gears are stronger than 3. |
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tristessa Samba Member
Joined: April 07, 2004 Posts: 3992 Location: Portland, OR
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Posted: Sun Jan 11, 2015 3:32 pm Post subject: |
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More planetary gears == stronger transmission. Yes, the Audi 5K weighs less than a fully loaded Vanagon, but the 5K turbos ranged from 140-220HP (vs the WBX 80-90HP) so the transmissions were stronger from the factory to handle the "extra" power. |
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