syncro TDI = trans death?

[dkoesyncro]

The other day I got to see boxes of transaxle parts and pieces that have been beaten by tdi death blows. I was astonished, I have always been a diesel lover and have a PD waiting to go into my Syncro. This was until I took my trans over to get a look at from a respectable opinion.

I just read through the "Live Work Wander" blog. They had Four rebuilds on the trans in 2 years time. This was what killed the syncro dream for them. Jed from "campervan culture" is killing them also. What do they have in common, long trips, heavy vans, lugging or is it low RPM/high torque. LWW has a PD, 170-190 ft.trq and CC a 1.7 idi maybe 90 ft.trq. The VW diesel makes peak torque below 2000 rpm. The popular gas conversions hit peak torque between 3500-5500. Do the higher revs ward off the death punch, aka diesel pulse? The Subaru 2.5 comes close to matching the tq. numbers of the PD but with about 3000 rps between them? How many 2.5s are eating gearboxes? The 1.8T is close, it hits peak torque around 3500 rpm and can keep climbing, how many have fallen victim here. Assuming all the popular engine conversions are stock or within the recommended tune for a vanagon. All these choices make under 200 hp and 200 tq. They just hit these numbers at different places in the power band.

Please, if you have a secret to the success of mating the TDI to the syncro. I want to know? This is just an out loud rant, I'm hoping to hear from the experts as to why...

[candyman]

From my reading on the numerous syncro trans threads there seems to be one similar factor in most premature failures and thats horsepower. Specifically anything over say 140 HP. Again, no data on this other than what has been expressed in these forums. Of course there are those that get bad rebuilds, or just plain abuse their boxes. But those that pay attention and still have failures relate it to too much HP that these boxes were not designed for. I keep my syncro stock, with stock wheels, 2.1 and drive it with respect and fingers crossed. I have a mr gas rebuild with about 25k on it and all seems well. MY syncro westy is 4900# - 5300#s depending on trips, so pretty dang heavy. So others will chime in here, but HP seems to be a reoccurring theme

[syncrodoka]

Torque, diesels make lots of torque.

[Waldi]

[clift_d]

TDi engines deliver lots of torque, but they also do this in quite sharp 'pulses' that really hammer the gears.

This sharpness comes down to the burn pattern of the fuel, which in a diesel is almost instant as the fuel almost entirely combusts at the moment of injection giving a sharp kick. In a petrol engine the fuel starts burning at the ignition point and the combustion spreads out through the fuel air mixture from there, giving a slightly more gradual burn pattern, and so a less sharp input of torque.
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1988 LHD T25 1.6TD Westfalia Club Joker syncro

[Wildthings]

I would wonder is there isn't a heavier flywheel available for some applications, maybe for use on an industrial or marine engine?

[clift_d]

There has been a recent tendency for TDi conversions to use a slightly larger dual mass flywheel and clutch setup to deal with the problem:

https://www.brickwerks.co.uk/t3-parts/engine-conve...i-gti.html
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1988 LHD T25 1.6TD Westfalia Club Joker syncro

[caravelle c]

The sharp torque curve is destroying the gearboxes! The transmission in Syncros were developed for the 1.9l WBX with 78hp and 130Nm of torque. So you will not find a solution that works properly, as long as it's based on the Syncro gearbox.

[vwwestyman]

The 091 gearbox from my '78 Bay was also seemingly killed by my TDI motor!

It was rebuilt in early 2015 and died in November of last year. 4th just stripped out or something.

I'd been emailing Paul G, aka "Gears" and he basically told me the same, that the torque/pulses of the motor killed it.

It is currently sitting in the warehouse at German Transaxle in Bend, for Paul to tear down and inspect. He says he's developed stronger gears for the syncro that are designed to take the abuse from the TDI and they should also fit my 091. I believe at the moment, he is on a ski trip, so I have to wait a few more days to hear the results of the autopsy.

We've also discussed changing out the gear housing to a new one by Weddle that allows for the splash plate that is common in new-built Vanagon boxes (there was no way to add this in 2015 when mine was built) and also a different shaft (don't remember which one) which would allow better oiling.

I'm interested in a dual mass flywheel, but my bellhousing is much deeper than most (from a Mexican baywindow bus with watercooled motor) and so the flywheel has a funky "snout" that pushes it out further from the motor and into the bellhousing. Trying to think of ways to deal with that.
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Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Waldi]

[vwwestyman]

[dobryan]

[vwwestyman]

[danfromsyr]

how many TDI swaps just leave them at stock HP and don't tweak the swap with additional HP mods?



here is my analogy for a TDI swap in a vanagon..

BIG MOTOR
small mechanical connection to the road.

how long do you think the crank, chain or bearings will last..

Link

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[dobryan]

And gearing/tires for lower rpms puts more stress on the gears too.

70 mph at 3800 rpm is less stressful on the gears than at 2800 rpm, especially up hills.
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[elizer]

Multiman MV has put some miles on his fas tdi/2wd. I think he did have to swap out a diff clutch or flywheel can't remember

My fas swap should be wrapping up in a couple weeks. The transaxle was rebuilt by gta with every single product that Paul (Gears) provides and will have a weddle oil cooler on it.

When I get some real miles on it I will be sure to drop by this thread if anything positive or negative happens.

There have been a lot of discussion on decouplers. At the end of it I still can't determine if it helps or not. But on long highway stretches will decoupling with a tdi help reduce stress on the gearbox?

[?Waldo?]

[Zeitgeist 13]

If these dastardly diesel engines are so hard on trannies, it seems that the trans in other models would be prematurely dying as well. This site is literally the only place I've ever encountered this purported phenomena.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[clift_d]

[elizer]