914/6 gearbox in a 914/4?, Will it fit? Options

[larss]

I have been offered a 914/6 tailshift gearbox for my -72 tailshift 914/4, are there any issues in fiitting it in my car?


/Lars S

[rgalla9146]

You'll need the 6 linkage from the shifter back.
Gulp.

[larss]

You'll need the 6 linkage from the shifter back.
Gulp.

Thanks, you mean all the way from the shifter back to the wery end?


/Lars S

[mepstein]

You could switch the tail cone of the 6 trans to one from a four. The 4 tail cone should be very inexpensive.

If it was me, I’d sell the six trans for $$$ and buy a rebuilt side shifter with all the parts needed to convert.

[Krieger]

The only difference between the two is the linkage, 2nd and 5th gear. I'd sell the 6 and pocket the change or build a 5 speed with a limited slip.

[jtf914]

The tail cover is different and you can't use the -6 linkage if you have a -4 because of the engine mount bar.

This pic shows the -6 cover on top and the -4 cover on the bottom.

As mentioned above you can swap the covers.

[rgalla9146]

I have to correct myself.
You'd have to change all linkage from just inside the tunnel rearward to the tail cover.
Not the optimum or inexpensive way to go.
I agree with the others.
Sell the 6 trans and convert to a side shifter.
Don't forget you'll need a side shift front engine bar.

[dr914@autoatlanta.com]

no reason to install it, first of all, having to use the six linkage which is impossible to find, the linkage will not clear the heat exchangers, secondly, the six linkage is not really any tighter than the early vague shifting of the four. Thirdly you can sell the six gearbox to a real six owner for enough to purchase a late transmission and linkage with all of the other parts to make a dramatic update to your car's shifting

I have been offered a 914/6 tailshift gearbox for my -72 tailshift 914/4, are there any issues in fiitting it in my car?


/Lars S

[SirAndy]

you can sell the six gearbox to a real six owner for enough to purchase a late transmission and linkage with all of the other parts to make a dramatic update to your car's shifting

(IMG:style_emoticons/default/agree.gif)

[larss]

Thanks all for responding!

You could switch the tail cone of the 6 trans to one from a four. The 4 tail cone should be very inexpensive.
---

So iIf I switch to a tail cone from a 4 I can still use all the linkage as I have it now (tail shift 4 linkage) on the 6 gearbox.

/Lars S

[dr914@autoatlanta.com]

also the six transmission has a different ring gear and pinion to deal with the engine power curve, bad bad bad idea to thy to install it on a four, very bad

Thanks all for responding!

You could switch the tail cone of the 6 trans to one from a four. The 4 tail cone should be very inexpensive.
---

So iIf I switch to a tail cone from a 4 I can still use all the linkage as I have it now (tail shift 4 linkage) on the 6 gearbox.

/Lars S

[oldie914]

Change the nose cone to 914/4 and it will work. I have a 914/4 nose cone I would sell you or exchange for the 914/6. I live in Germany so shipping is not so expensive.
That said, you would probably be better off to find a 914/4 transmission or fix yours.

[larss]

also the six transmission has a different ring gear and pinion to deal with the engine power curve, bad bad bad idea to thy to install it on a four, very bad

Thanks again, no this is no longer likely to happen just want to know what the alternatives would mean.

I have a 2056 in my car with 2.0 D-jet, runs nice, should this engines power curve be so far from the 2.0 110hp six that the trans was geared for?


/Lars S

[dr914@autoatlanta.com]

yes

also the six transmission has a different ring gear and pinion to deal with the engine power curve, bad bad bad idea to thy to install it on a four, very bad

Thanks again, no this is no longer likely to happen just want to know what the alternatives would mean.

I have a 2056 in my car with 2.0 D-jet, runs nice, should this engines power curve be so far from the 2.0 110hp six that the trans was geared for?


/Lars S

[davep]

I believe you are mistaken there George. The 914/4& 914/6 transmissions all had 7:31 pinion and ring gears, with the exception of the Sportomatic versions with 7:27 ratio. The 7:31 was common to most 911 & 912 transmissions with only a few exceptions until about 1975 when the 8:31 began to supplant it. The 6:29 ratio for the 1969 912 was considered very weak.

[dr914@autoatlanta.com]

Dave you are certainly right, I was thinking of the gear ratios that are different for some of the gears, the sportomatic has the different ring gear and pinion ratio. Thanks for the clarification

I believe you are mistaken there George. The 914/4& 914/6 transmissions all had 7:31 pinion and ring gears, with the exception of the Sportomatic versions with 7:27 ratio. The 7:31 was common to most 911 & 912 transmissions with only a few exceptions until about 1975 when the 8:31 began to supplant it. The 6:29 ratio for the 1969 912 was considered very weak.