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Re: Convertible D 86007

Posted: Wed Sep 21, 2022 4:47 pm
by Peter Silten
Ds came with either the 644 transmission or the 716 transmissions, depending upon the date of manufacture. And both were available with BBAB gearing. Jon, are you saying, for example, that the BBAB gears used in the 644 transmission are not the same as the BBAB gears used in the 716 transmission? If so, this is news to me.

Re: Convertible D 86007

Posted: Wed Sep 21, 2022 5:05 pm
by Jon Bunin
Peter Silten wrote:
Wed Sep 21, 2022 4:47 pm
Jon, are you saying, for example, that the BBAB gears used in the 644 transmission are not the same as the BBAB gears used in the 716 transmission? If so, this is news to me.
Peter, 716 transmissions had 716 gears with 716 synchromesh.

Porsche did not build 716 transmissions for Convertible D's with 644 (519) gears and 644 (519) synchromesh.
I'm sure Vic never said that occurred, as Dave implied. If he actually did, then please post a link to his comments.

As you said initially, Ds came with either the 644 transmission or the 716 transmission.

Re: Convertible D 86007

Posted: Wed Sep 21, 2022 10:26 pm
by DaveErickson
Jon, here is the thread that was the source of my information:
viewtopic.php?f=1&t=42048&hilit=716+644+D

Re: Convertible D 86007

Posted: Wed Sep 21, 2022 11:29 pm
by Jon Bunin
DaveErickson wrote:
Wed Sep 21, 2022 10:26 pm
Jon, here is the thread that was the source of my information:
viewtopic.php?f=1&t=42048&hilit=716+644+D
OK, well that was confusing, and Jerry L never followed up to confirm the transmission stampings.
Vic himself will hopefully clarify what he posted, but here's the way I'm reading it...

Vic's post #11: "The 716/2 would indicate it should have 716/741 gears in it. However, the serial number puts it in the series that still used the 644/519 gears..."

Vic's post #9: "Yep; the good old conv D trans conundrum. 23379 is a 644. You need a 644 4C. 26114 is a 716; different synchros; same as a 741."

Jerry was saying the Conv D transmission was stamped 23379 and 716/2 ... ? ... but it was a couple of hours away and he was going to check it again.
Transmission 26114, a 716/1, was in another car, a '59 coupe.

As Vic said, "23379 is a 644" ...and... "the serial number puts it in the series that still used the 644/519 gears..."
I'm sure that either Jerry mixed up or mis-read some numbers, as Larry C suggested, or that the Conv D transmission was re-stamped by someone later.

Vic's post #7: "The conv Ds that were built with BBAB gears still used the 644 gears. The ones built as real 716s used the 716/741 gears."

I'm sure Vic meant the transmissions that "still used the 644 gears" were 644 transmissions.
He didn't say Porsche built 716 transmissions with 644 BBAB gears. They would have been built with 716 BBAB gears, as he said in post #11.

Re: Convertible D 86007

Posted: Thu Sep 22, 2022 7:42 am
by Vic Skirmants
"I'm sure Vic meant the transmissions that "still used the 644 gears" were 644 transmissions.
He didn't say Porsche built 716 transmissions with 644 BBAB gears. They would have been built with 716 BBAB gears, as he said in post #11."

Thanks, Jon, for helping to clarify things.

Re: Convertible D 86007

Posted: Thu Sep 22, 2022 10:09 am
by DaveErickson
Jon, thanks for the clarification. What are the differences between 716 transmissions and 741’s? Can the internals of a late 741 be moved into a 716?

Re: Convertible D 86007

Posted: Thu Sep 22, 2022 2:36 pm
by Jon Bunin
DaveErickson wrote:
Thu Sep 22, 2022 10:09 am
What are the differences between 716 transmissions and 741’s? Can the internals of a late 741 be moved into a 716?
Dave, the first 741 transmissions were basically 716 transmissions redesigned for use in a 356B, with shift linkage that passed under the rear torsion tube, not over it.
They also had a new clutch release bearing arrangement.

The wide 1st gear of later 741 transmissions will not work in a 716 case. The internal shift rods and shift selector of any 741 will not work in a car with 356A shift linkage.
The later differential housings were also wider, but the earlier input shafts can be modified for sufficient clearance.

Re: Convertible D 86007

Posted: Thu Sep 22, 2022 6:38 pm
by DaveErickson
Thanks Jon, that clears up a lot. To summarize my understanding: to use a 741 in an A, you need the nose piece from a 644 or 716, and you need to use the 644/716 hockey stick, shift rods and shift forks. Is the intermediate plate the same for both?

Re: Convertible D 86007

Posted: Thu Sep 22, 2022 9:29 pm
by Martin Benade
The Konis will probably smooth out. I was pretty unhappy with my new Koni shocks, but after 1000 miles they were ok.

Re: Convertible D 86007

Posted: Fri Sep 23, 2022 2:38 am
by Jon Bunin
DaveErickson wrote:
Thu Sep 22, 2022 6:38 pm
Is the intermediate plate the same for both?
The intermediate plate is slightly different, but can still be used for a 741-into-356A conversion.

Re: Convertible D 86007

Posted: Fri Sep 23, 2022 5:54 am
by Harlan Halsey
My recollection is that the 644 and 716 are center shift rod transmissions while the 741 is a bottom shift rod transmission. The 716 and the 741 have a camber compensator mount. Any gear cluster with its intermediate plate will fit any case, and any nose piece will fit any intermediate plate. (See Vics correction below.) The shift rods and the hockey stick go with the nose piece.
Obviously, you can swap gears within any transmission type. Since the shafts are the same diameter and the spacing is the same and the dog rings are the same you can sometimes swap gears between transmission types. The rollers and races go with the gears. The 644 is all separate rollers, the 741 is all caged rollers, and the 716 is half and half. The gears are not all the same width between transmission types. I cannot see why anyone would want to swap gears between transmission types for street use. But for a racing box sometimes it might be desirable. To get the short forth gear I wanted for the Carrera 716 I had a 644-4th narrowed to fit. :D

Re: Convertible D 86007

Posted: Fri Sep 23, 2022 7:49 am
by Vic Skirmants
The camber compensator mount did not appear until January 1961. A 741 nose can not be used on a 644/716 intermediate plate.