does '70 bus have syncro?

[justgimmecoffee]

this has probably been answered but I can't find it after searching here and Google.

Does the '70 bus have syncromesh for first gear? Or do I have to be at a dead stop before the transmission will go into first gear?

My dad's 63 bug was that way.

-Barry

1970 Bus with ASI camper conversion
1600 engine

[vwlover77]

From the Bentley '68-'79 manual: "The four-speed manual transmission is standard equipment on all Type 2 vehicles and is fully synchronized in all forward gears."

[Bookwus]

Hiya Barry,

It's been my experience that first gear is snchronized as long as you are not going any faster than 10 or 11 mph. I dunno if that makes any mechanical sense, but it sure has run true with my Bus.

[vwlover77]

It makes sense. The transmission has an input shaft that connects to the engine through the clutch, and an output shaft that drives the wheels through the differential gears. The purpose of the synchronizers is to match up the speeds of the gears on the input and output shafts so the gears mesh smoothly when you shift. When you try to downshift to first gear, the synchronizers are trying hard to spin the input shaft up to whatever the engine rpm would be at that road speed in first gear. You can imagine how fast that would be at anything over 10-15 mph, and it's hard for the synchronizers to do that.

[Amskeptic]

You can imagine how fast that would be at anything over 10-15 mph, and it's hard for the synchronizers to do that.

Yes let's imagine. . . . early bus to '74.
At 10 mph, the wheels are travelling at approximately 133 rpm. So is the ring gear in the differential. Multiply that by the rear axle ratio (5.375) and you now have the output shaft rpm of 716 rpm. Before you select 1st gear at 10 mph, you can assume that the engine and clutch and input shaft are around idle speed, particularly if you are dawdling. Now multiply the 716 rpm of the output shaft by the 1st gear's ratio of 3.80. and in order to engage 1st gear to the output shaft, the synchro has to spin up the input shaft and the clutch disk from idle (800 ish?) to 2730 rpm. How utterly barbaric and cruel of you.
But if you are enlightened, you will rev the engine with your foot off the clutch gearshift in neutral to 3,000 rpm, dip the clutch and perform a magnificently smooth shift into 1st with nary a jerk.
Colin

[vwlover77]

But if you are enlightened, you will rev the engine with your foot off the clutch gearshift in neutral to 3,000 rpm, dip the clutch and perform a magnificently smooth shift into 1st with nary a jerk.

Colin is enlightened as he was able to demonstrate this to me in my own Bus numerous times when we met last June.

I have not yet reached his state of enlightenment, but continue to practice... ohhhhhhhmmmmmmmmmm.......