TheSamba.com :: View topic - Building a better Vanagon automatic transaxle

Sun Jan 11, 2015 11:36 am

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

Sun Jan 11, 2015 11:48 am

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..

Sun Jan 11, 2015 12:04 pm

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

Sun Jan 11, 2015 12:53 pm

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

Sun Jan 11, 2015 12:56 pm

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

Sun Jan 11, 2015 1:21 pm

Curious, what is the draw to the Audi Transmission?
More robust?
If so how?
A Vanagon Weekender is said to weigh 5160 lbs.
An 86 Audi 5000 3350lbs.

Or better parts availability?

Anyway.........

This thread will have way Too much thinking for me but I'm watching with interest.

:popcorn:

Dave

Sun Jan 11, 2015 1:34 pm

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.

Sun Jan 11, 2015 1:40 pm

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.

So in Plain English?

These parts wear less?
Last longer?
In my brain and in my experience more moving parts often equal less reliability and greater chance for a breakdown.
I of course am thinking manual vs electric windows, mirrors, manual steering, etc.
Transmissions are not my Forte.

Mercedes currently priduces some of the most frequently repaired vehicles on the market today. Not for mechanical reasons but due to the complexity of modern creature comforts and monitoring systems.

Dave

Sun Jan 11, 2015 1:40 pm

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.

Sun Jan 11, 2015 1:44 pm

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

Sun Jan 11, 2015 2:16 pm

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...

Sun Jan 11, 2015 2:17 pm

I too have the gowesty cooler but have yet to install it. These Derale products look awesome.. I may go this route as I like the fact that it has a fan incorporated...

Sun Jan 11, 2015 2:48 pm

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.

Sun Jan 11, 2015 2:56 pm

Jake de Villiers wrote: 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...

Hmmmmmm I get my weight ratings from Volkwagen AG West Germany........... You get yours from?

Granted this is Maximum...... But you need to plan for this loaded weight.

Dave

Sun Jan 11, 2015 3:04 pm

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.

Sun Jan 11, 2015 3:13 pm

IdahoDoug wrote: 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.

Well.......... Except the Audi 5000's weight posted is also maximum loaded...... No?
In essence this Audi trans is designed to move a maximum 3500 lbs, an empty Camper easily STARTS at this 3500 lb weight and goes up from there.

Just thinking out loud, as I mentioned, I'm no expert at Transmissions.

Dave

Sun Jan 11, 2015 3:21 pm

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?

Sun Jan 11, 2015 3:25 pm

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

Sun Jan 11, 2015 3:32 pm

Its all about gear contact area, more contact area more strength. ie 4 gears are stronger than 3.

Sun Jan 11, 2015 3:32 pm

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.