If you've read my other post, you know that I'm not too happy with my 915 transmission. I've heard that the 4 speed 930 transmission is an awesome shifting gearbox...but it's a 4 speed which turns me off.
Are there any other options?

I'm considering getting mine rebuilt...but from what I've read it doesn't take much to toast a syncro in the 915. I'd like to hear some other opinions!

 

You can also install a G-50 transmission adapted for use with the pre-87 911 body. One source is Patrick Motorsports <a href="http://www.patrickmotorsports.com/g50.html" target="_blank">here</a>. (no affiliation, etc)

 

Ditto to what Bill said. But it's not cheap. If you really don't like the 915, and can't live with it, your best bet is to sell the car and buy a G50 equipped car IMHO.

 

When you say "adapted", what exactly do you mean?

I don't think selling the car and getting something else is an option...it's not THAT bad and the rest of the car is SO cherry.

I'm thinking about replacing the syncros myself, but I still havn't decided what I want to do. It looks like the G50 can be had for less than 2k, which isn't all that bad...I'm thinking I might be able to get 1K for my 915...Just depends on what's involved in adapting the G50 as mentioned above.

 

A G-50 conversion isn't exactly a bolt-in process. Besides having to get the G-50 modified by shortening the housing, you have to plumb the hydraulic clutch assembly, new pedal cluster, and all kinds of fun and expensive parts. The process is described as a PITA.

Typically, it's $5k for parts. Then you have labor. Not too cost effective. Better to get the 915 rebuilt by a reputable source. A 915 properly set up will be fine to drive..

rjp

 

I've gotta agree w/ Randy on this one. The G50s are best suited for very high torque turbo motors. The 915 is considerably lighter than a G50 and shifts fine as long as it's properly set up. It will never be a drag race transmission as hurried shifts are a no no. Reliability is there also. I had a stock mg. case 915 that never gave a whimper in 7 yrs in front of my 964 engine. It was retired only because an '84 lsd trans was found at a reasonable price. The later 84-86 915s are the beefiest of the series, and lsd versions also have better metalurgy.

The G50 while a fine trans is heavy, and not an easy fit in an 86 or earlier chassis. If I were going to all the touble to fit one I would give serious consideration to a G50 6spd. Which while even more work also gives you more gears.

 

ok, the G50 is out of the question then.
I guess first I'm going to try Swepco transmission fluid...right now I'm running redline, but everybody suggests swepco.
If that doesn't help, I will probably put syncros in. I just want to be able to shift from 1st to 2nd at something higher than 2500 RPMs. The rest of the gears change fine, its just the 1st -&gt; 2nd that irks me.

How are syncros toasted in the 915? Is it caused just by gradual abuse [poor shifting habbits]? Or can you ruin one with just one or two mistakes?

 

Best solution seems to be easy shifting - no power shifting or skipping gears, never force a shift, and don't shift from 2nd to 1st at speeds higher than 10 MPH. Keep fresh lube in it at all times. They're not like watercooled VW transaxles, someone told me to treat it like an aircooled VW transaxle. Seems to work for me.

PS: stick with standard gear lubes, stay away from synthetics in that thing. Works better that way.

rjp

 

[quote]Originally posted by Fahrvergnuugen:
<strong>ok, the G50 is out of the question then.
I guess first I'm going to try Swepco transmission fluid...right now I'm running redline, but everybody suggests swepco.
If that doesn't help, I will probably put syncros in. I just want to be able to shift from 1st to 2nd at something higher than 2500 RPMs. The rest of the gears change fine, its just the 1st -&gt; 2nd that irks me.

How are syncros toasted in the 915? Is it caused just by gradual abuse [poor shifting habbits]? Or can you ruin one with just one or two mistakes?</strong><hr></blockquote>

Hi Paul:

First,...(standing on soapbox) Never, ever run a synthetic in any Porsche transmission aside from the G-50 and later series........its way too slippery to work and all you'll suffer is sticky, baulky, shifting and much higher rates of wear inside that thing. Use Swepco # 201 and that will really help.

Syncro's get toasted by someone making fast, hard shifts in these things. Porsche transmissions with baulk-ring syncromesh (901-915-930) do not like to be hurried, and will last almost forever when rebuilt properly and shifted with a firm, patient hand,...

These are VERY durable when treated properly but do not suffer ham-handed operation. Those techniques will put substantial dents in your pocketbook.

 

I have a 1983 911SC that I recently purchased that has a rebuilt 915 tranny in it,I know the shop that did the rebuild,they are local and are Porsche experts with a long history of sevicing Porsches.The transmission shifts great for a 915,still a little balky,but thats the way these are.I do not speed shift,you can feel when the synchro is saying O.K. time to go into gear,and it will go into gear,no problem.I do not know what brand of oil is currently in the tranny but I am going to change it to Swepco here shortly.I believe that a 915 when rebuilt properly and used with good oil and SHIFTED properly will last a long time!! My 2 cents. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

[quote]Originally posted by rfuerst:
<strong>you can feel when the synchro is saying O.K. </strong><hr></blockquote>

Thats a great way to phrase it!

w/o Swepco the feel is gone

 

Thanks, you guys have been a great help.
I just got this car about a week and a half ago...it came with redline in it, but I will be changing it out ASAP. To make matters worse, it is very cold out here in the NE and redline turns into molasses in these conditions.
The car is now hibernating for the winter, but come May, I will be able to make a more educated descision about what to do.

I'm hoping it's not quite toast yet...we'll see how it shifts when its warm with swepco.