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Sodo Samba Member
Joined: July 06, 2007 Posts: 9616 Location: Western WA
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Posted: Mon Feb 04, 2019 9:57 pm Post subject: Syncro transaxle shifts "slower" than 2WD transaxle |
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Here's some info that I got from talking with SyncroShop (Tom Lengyel).
No doubt other people know it as well,
but I made up a SAMBA diagram hoping its easier to understand the reasons.
Syncro and 2WD have basically the SAME external shift rods, but this discussion relates to the transaxle INTERNAL differences.
Hope this helps to understand the Syncro. There are more gears than what's shown in the "Syncro trans side-view cutaway". They are red in the "isometric" of the low gear housing.
SyncroShop says "shift with two fingers".
Which will be "a little slower" than shifting a 2WD.
You need to allow a little more time for the undersized synchronizers to match revs with the added gear weight.
Shifting from 3rd to 4th for example, just imagine how fast the granny idler set is spinning! being a 6:1 it's spinning about than 6x the speed of top gear. _________________
'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
Last edited by Sodo on Mon Mar 04, 2019 10:26 am; edited 6 times in total |
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IdahoDoug Samba Member
Joined: June 12, 2010 Posts: 10251 Location: N. Idaho
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Posted: Mon Feb 04, 2019 10:50 pm Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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I like the SyncroShop's shifting advice. Over the years, I've driven a lot of valuable manual transmission cars and a lot of old manual transmission cars. That two finger rule will ensure you are gentle on the hardware and its my own mantra for those situations as well.
On the opposite end of the spectrum, I find it distracting to the point of wanting to say something when I'm in a manual car where the driver jams gears into place so firmly you'd swear the shifter is flexing.... _________________ 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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levi Samba Member
Joined: February 11, 2005 Posts: 5522 Location: Las Vegas
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Posted: Tue Feb 05, 2019 1:00 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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That doesn't mean I'm going to be shifting like this guy.
No.
https://youtu.be/CM76f7nChSU _________________ One of these days I'm gonna settle down,
but till I do I won't be hangin round.
Going down that long lonesome highway,
gonna see life my way
https://youtu.be/cSrL0BXsO40 |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17155 Location: Retired South Florida
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Posted: Tue Feb 05, 2019 5:13 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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When you say 1st gear on the syncro to be clear you are referring to the "granny" gear? _________________ ☮️ |
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tjet Samba Member
Joined: June 10, 2014 Posts: 3533 Location: CA & NM
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Posted: Tue Feb 05, 2019 6:34 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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I don't think he's referring to the "low" granny gear. I attempted to shift from the granny gear to 1st while moving = bad idea. I usually make a complete stop, then move it into 1st. |
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Pcforno Samba Member
Joined: October 14, 2014 Posts: 575 Location: Santa Fe, nm
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Posted: Tue Feb 05, 2019 7:19 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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When my trans is cold, I double clutch and rev match until it’s warmed up |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9616 Location: Western WA
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Posted: Tue Feb 05, 2019 9:06 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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MarkWard wrote: |
When you say 1st gear on the syncro to be clear you are referring to the "granny" gear? |
oops... they call granny 1st because on the 5 speed (which a Syncro is) it's 1st gear. I hope that's the only "error" and I edited the image. Changed "First" to "Low" and re-posted.
There HAS to be more errors.
I suspect that the 5 speed 2WD having a little more gear cluster rotational inertia (than the 4speed 2WD) would be a little harder to shift than a 4 speed. _________________
'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
Last edited by Sodo on Tue Feb 05, 2019 10:02 am; edited 3 times in total |
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?Waldo? Samba Member
Joined: February 22, 2006 Posts: 9752 Location: Where?
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Posted: Tue Feb 05, 2019 9:11 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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I have owned/operated both 4 and 5-speed 2WD transaxles and have not noticed the 5-speed to be any harder to shift. |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9616 Location: Western WA
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Posted: Tue Feb 05, 2019 9:18 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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It could be subtle. And may not show up unless you are the type to "shift hard & fast". The single gear pair of the 5 speed may be within the capability of the 2WD synchros. Just a guess. I've never even seen a 5 speed 2WD.
And 4WD has a lot more gears than the 5 speed 2WD. There's the double-reduction to get to 6:1 for granny. And they are big & heavy too, and add bearings and shafts. _________________
'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
Last edited by Sodo on Tue Feb 05, 2019 9:23 am; edited 1 time in total |
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gears Samba Member
Joined: October 28, 2002 Posts: 4391 Location: Tamarack, Bend, Kailua
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Posted: Tue Feb 05, 2019 9:23 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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When we ran out of OE Syncro reverse gears, I had a lighter version made
.. I've also lightened G and "cluster" gears to see if that helps.
I've got one more trick up my sleeve to help eliminate baulky 2nd gear shifting .. _________________ aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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?Waldo? Samba Member
Joined: February 22, 2006 Posts: 9752 Location: Where?
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Posted: Tue Feb 05, 2019 9:27 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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Sodo wrote: |
It could be subtle. And may not show up unless you are the type to "shift hard & fast"... |
I'm definitely not a 'shift hard & fast' type, lol. I'm a 'hold gentle pressure and wait for it to plunk into place' type. |
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outcaststudios Samba Member
Joined: February 09, 2015 Posts: 1732 Location: Maine
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Posted: Tue Feb 05, 2019 10:06 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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?Waldo? wrote: |
I have owned/operated both 4 and 5-speed 2WD transaxles and have not noticed the 5-speed to be any harder to shift. |
so if i follow this then the 5 spd tranny with the granny gear ( ive heard it referred to as a 6 speed) for 2wd is similar to the syncro trans? i have a transmission from europe with a granny gear and then four above plus reverse so a total of 6 gears.2wd. _________________ '88Doka JX td
'69 westy
(rip)couple bugs
(rip)three type III"s
(rip) '81 vanagon
a bunch of french stuff,and 9 motorcycles.
https://www.thesamba.com/vw/classifieds/detail.php?id=2573791 |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9616 Location: Western WA
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Posted: Tue Feb 05, 2019 10:06 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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The "5 speed tranny" is similar to the Syncro, because they added another forward gear pair outside of the main transmission housing. But the 5-speed does not have the compound reduction (no granny). First gear in the 5 speed is a typical 4:1 first gear as limited by the shaft spacing.
Generally you just count the forward speeds.
gears wrote: |
When we ran out of OE Syncro reverse gears, I had a lighter version made
.. I've also lightened G and "cluster" gears to see if that helps. |
Would be interesting to see a pic of the "lightened gears" next to the originals. _________________
'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 |
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?Waldo? Samba Member
Joined: February 22, 2006 Posts: 9752 Location: Where?
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Posted: Tue Feb 05, 2019 10:39 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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The 2WD 5-speed does not have a 'granny gear'. It has 5 forward speeds all of which are used in normal driving. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17155 Location: Retired South Florida
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Posted: Tue Feb 05, 2019 11:13 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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Like shifting into reverse, I would expect to be at a dead stop to select "low, 1st, or granny gear in a syncro. I recall the ratios are similar between reverse and low in a syncro gear box. While both are synchronized, I think its ambitious to think you could select either low or reverse with forward momentum winding down in the gear train.
My owners manual specifically states "Shift into reverse only when the vehicle is not moving. There is not a warning for shifting into Low gear. Once I get my syncro on the road, I will expect most of the time, I will be using the other 4 forward speeds and will be selecting low as I would reverse from a stop, unless I manage at some point to put myself into a hairy spot some day.
I do like the pictures of the lightened gears above. My racing transmission has lightened gears. Nothing wrong with lightening rotating mass if strength is not impacted. _________________ ☮️ |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9616 Location: Western WA
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Posted: Tue Feb 05, 2019 11:37 am Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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Pcforno wrote: |
When my trans is cold, I double clutch and rev match until it’s warmed up |
Same here.
Anytime you hear or feel "crunch" ; the slider hub colliding with your idler gear has just let loose a little bit of steel trash into your "wet stuff". If you shift such that all shifts are smooth & easy, your fluid will remain a proper lubricant for longer. PC your filtering no doubt helps this situation.
Syncroshop thinks this is one of the main reasons that Syncro trans don't last as long as 2WD transaxles. Because drivers shift them too fast, they pollute the lubricant. Couple that problem with THIS page (no lube changes):
...with these two assaults (and one of them compounding), it seems plausible that the Syncro gearbox would NOT last as long as a 2WD. And all this gets worse with a big engine, high speeds, thinned out oil.
The good news is, there's a SIMPLE solution that almost anyone can DO.
Shift slowly, quietly
---AND---
Keep your lubricant clean
---AND---
big engine crowd----Don't drive fast
OK.... that last one..... "almost anyone can do" is not so likely.
But some can. Our illustrious member "gears" drives his SVX van 62mph. _________________
'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 |
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flomulgator Samba Member
Joined: March 07, 2013 Posts: 951 Location: Leavenworth, WA
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Posted: Tue Feb 05, 2019 12:06 pm Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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Thank you Sodo for showing the issue and thank you Gears for trying to address it! _________________ She's built like a steakhouse, but she handles like a bistro! |
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tjet Samba Member
Joined: June 10, 2014 Posts: 3533 Location: CA & NM
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Posted: Tue Feb 05, 2019 5:45 pm Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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MarkWard wrote: |
...
My owners manual specifically states "Shift into reverse only when the vehicle is not moving. There is not a warning for shifting into Low gear. ... |
That's how I do it, for both reverse or granny. It also helps if you have the ability to let it roll slightly when shifting. That's how I needed to shift my stock '59 Chevy pickup into 1st (& reverse) with the original 3 speed & 6 cyl...
Last edited by tjet on Wed Feb 06, 2019 12:53 am; edited 1 time in total |
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outcaststudios Samba Member
Joined: February 09, 2015 Posts: 1732 Location: Maine
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Posted: Tue Feb 05, 2019 8:32 pm Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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Sodo wrote: |
The "5 speed tranny" is similar to the Syncro, because they added another forward gear pair outside of the main transmission housing. But the 5-speed does not have the compound reduction (no granny). First gear in the 5 speed is a typical 4:1 first gear as limited by the shaft spacing.
Generally you just count the forward speeds.
gears wrote: |
When we ran out of OE Syncro reverse gears, I had a lighter version made
.. I've also lightened G and "cluster" gears to see if that helps. |
Would be interesting to see a pic of the "lightened gears" next to the originals. |
hmm, i see. i always assumed my doka had that 5 speed tranny for pulling weight. i can only use that first gear from a dead stop really, and it feels like i have to shift after only moving maybe 10-12 feet...good to know. _________________ '88Doka JX td
'69 westy
(rip)couple bugs
(rip)three type III"s
(rip) '81 vanagon
a bunch of french stuff,and 9 motorcycles.
https://www.thesamba.com/vw/classifieds/detail.php?id=2573791 |
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Reventlos Samba Member
Joined: May 24, 2009 Posts: 103 Location: Costa Mesa, CA
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Posted: Tue Feb 05, 2019 9:09 pm Post subject: Re: Why the Syncro is more difficult to shift than 2WD |
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Random observations: I've owned four Syncros over the years. I had two rebuilt with different R&P and an aftermarket Weddle 1.14 3rd gear. Both of these boxes crunch(ed) shifting into 3rd. They are otherwise fine, but do seem stiff compared to a 2WD. My doka (around 135K km) has never been apart, and shifts like a dream. FWIW, I have Swepco 202 in the doka (stock motor), and Swepco 210 in the 1.8T equipped tintop. I change the fluid yearly, and so far it has been very clean, and the 1.8T box has held up great with 200+HP.
Any other anecdotal data on these aftermarket gears being noisier/balkier? |
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