915 Transmission - Adjust your Shift Coupling!

[jcsjcs]

All -

Just reaching out to those of you with 915 Transmissions and reminding you to adjust that shift coupling if you are having any shifting problems. It may just solve problems that you believe are a lot more serious.

I purchased my car about 1.5 years ago ('84 Targa) and now have it well sorted out. The most concerning issue has been shifting - and I have found that adjusting the shift coupling has made an amazing difference for the second time this weekend.

This time I was starting to have some grinding issues going into 2nd gear. While the car has always required some patience when shifting into 2nd (generally requires a pause until the shift is easy) - matters seemed to be getting worse.

I spent about 5 minutes adjusting my shift coupling this weekend - ensuring that my shift knob was not too far forward in first and not too far back in second - and it is shifting well again.

The first time I adjusted the car was popping out of 1st gear on startup. Turned out that I was not able to fully engage 1st as the shift lever was hitting the front of the shift gate (not sure of the correct term for this area.)

I have completed some other work and expect to replace the clutch and transmission as some point in the future - but so far the minor stuff has solved any immediate problems.

Work completed so far (in order of positive impact) :
1) Adjusted Shift Coupling (twice)
2) Installed Seine Systems Shift Gate AND removed Shift Boot (cause it looks cool). This really increased my confidence for picking the right gear when driving hard.
3) Replaced fluid with Swepco 201

4) PLANNED for this weekend: replacing shift cable & clutch pedal helper spring. My clutch pedal requires a lot of effort to engage. I live in Brooklyn, New York City - so I shift A LOT.

Hope this helps any of you with shifting issues on the 915.

Jonathan

[wnsgc]

Greetings,

I've had my 85 for 3 years now and have learned that shifting a 915 transmission is an art, not to be taken for granted. I too had the popping issue out of 1st and the need to pause before shifting into 2nd. Recently I replaced the engine and tranmission mounts with Club/Sport mounts (they are used in the cabriolet). It made a huge difference in shifting immediately.

When I first bought my car, people told me about using Swepco 201, so I draining the fluid and replaced it with Swepco. I was also considering a short-shift kit. When I told my mechanic about the Swepco and the short-shift kit, he smiled and said "great, I love guys like you..."

I asked him what he meant, his response was very clear "most of the transmission rebuilds I do are on units with a short-shift kit with Swepco inside". According to him, the short shifter puts too much stress on the inner workings and the Swepco is a bit too sticky. I will agree with the later comment as I when I was putting in the Swepco, I couldn't believe how thick and sticky it actually was. My mechanic recommended Mobile1 gear oil, which I put in, based upon his recommendation and it has made shifting much easier.

As an FYI, my mechanic has been working on Porsches for over 30 years and is recognized in the NJ area as an authority on 911's. So I trust his opinion and guidance. I'm just telling you this, because I for one and still learning about these 911's with the 3.2 and 915.

Good luck!

[redranger]

I'm no expert, but I think your mechanic has it wrong. Everything I've read and been told by experienced p-car mechanics is that synthetic is not supposed to be used in the 915 gear boxes. Swepco is the brand to use for 915s. Synthetic gear oil is reserved strictly for the g-50 boxes.

I've got a short shift in my 911 and I use swepco, no issues 102k miles...knock on wood

[dlague]

Interesting. I have Swepco in my trans and a factory short shift kit. A wevo coupler and Wevo shift gate and a sweet shifting trans which I have driven for 100K.

I think you should get a new mechanic.

[wnsgc]

I knew my comments would cause a stir and I even hesitated as I typed them into the reply box. That being said, "to each his own". I'll stick with my mechanic as I trust him, as do the hundreds if not more that follow him where ever he is.

Regardless of the fluid issue, I have read (on this forum) about the stress on the 915 caused by short shirt kits.

[sc_rufctr]

When new the 915 was often described as a good gearbox.
However poor maintenance, time and mileage have all had an effect on how these gearboxes shift today.

I agree with you that a shorter shifter would only make the problems of this gearbox more noticeable.
I run a Rennshift in my car but I have it adjusted to 20% reduction rather than the 33% reduction and using SWEPCO oil.

My recently refreshed (not rebuilt) gearbox shifts superbly.

The ability to choose the amount of reduction was a major factor in choosing the Rennshift over the WEVO and others.

Another thing to think about...
The legendary 2.7 RS has a 915 gearbox and these cars are praised for the way the drive and handle.

[Kemo]

This goes back to the original post... You can use 914 shift coupler bushings which are perfectly round instead of oval like the 911. Mine were toast and probably a little more oval than they should have been. this made a big difference in my shifting.

btw: I use Swepco with Rennshift at 20% throw and sport mounts. I thought about a wevo coupler but went with the 914 bushings due to cost.

[KCTarga3.2]

Jonathan,
Nice post. I purchased my 84 Targa about 1.5 years ago as well. +1 on the shift coupling. I installed a wevo coupler and I thought it was a night and day difference. Although it could be that I am just in denial that I need to drop a few thousand for the 2nd gear synchro rebuild.

[snbush67]

Any time you put replace 50K gear oil it is going to feel great whether it is swepco or generic. I agree with the mechanic but I like the short shifter.

[jcsjcs]

I definitely believe that the Wevo Coupler made a big difference for some of you. Changing mine is on the list but can't do it quite yet financially!

As far as wnsgc having to change his mechanic - I disagree. I really think that we as owner's of our cars are better at determining how to deal with the stuff that requires research, TLC, and knowing our cars intimately.

My car required some minor work due to a towing incident last year and the shop did a great job of helping me resolve the number of issues, implementing some upgrades, and resolving a few problems that were missed by another shop during a PPI. They made a blanket statement about the transmission however - assuming that I would need a rebuild sooner than later. It took my "TLC" and attention to the small stuff to sort that issue out.

Yes, they probably should have dealt with the Shift Coupling - but the issues I had with shifting required a lot of driving/shifting (I live in Brooklyn, NYC) to fully identify and really sort out.

[Winter]

Refreshing the bushings was one of the first jobs I did on my car. Removing the pin in the coupling was a PITA, but it was totally worth it.

I'm not claiming my car shifts "like new" but it was really sloppy before, and I'm really happy with the improvement. Your advice is well taken, and hopefully will help others resolve issues without spending big bucks to do so.

---

Tom '75 targa

[jcsjcs]

Tom - Just to be clear, are you talking about this bushing set?

http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=PEL-BUSHKIT1N

Looks like another near term project for me!

[JBO]

I have spoken and dealt with many 911 mechanics that don't think SWEPCO provides any real benefit (including the one that rebuilt my 915). However, most agree that it is better not to use synthetic in the 915, but to use a quality 80-90 GL-5 dino fluid. If I remember correctly John Walker, who is beyond reproach, agrees with this. I used SWEPCO after my rebuild anyway, and may use it again (though approx $60 a gallon for non-synthetic fluid seems crazy, if its not really worth it). I use sythetic engine oil as I'm convinced that there IS a benefit to justify the higher cost. SWEPCO I'm still not sure.

[jcsjcs]

I didn't notice any difference after changing to SWEPCO. I will continue to use it though - as $60 is not a lot in the scheme of things.

Thinking about moving to synthetic oil - probably on my next oil change - but that 's a different thread entirely!

[greg79s]

All,

I plan on dropping the engine and 915 transmission on my Euro 85 Carrera SE to rebuild the gearbox. The trans has the same symptoms as you all describe. I am going to try the shift linkage service first. The original owner installed a short shift kit when he had the car delivered which probably contributed to the syncro wear on the 2nd gear. Still have the original stock shifter. What is your opinion on the stock versus the short shift type?

Eventually, the trans will need a rebuild.....has anyone tried a gearing change to lower gearing?

[billybek]

What reduction in throw could you expect from a factory short shifter?
I put Swepco in the SC two years ago and don't regret it. It (at least in my mind) made a marginal difference in shifting but it does need a bit more work.

[jcsjcs]

Greg79s - Defintely do the small stuff 1st - you never know what will be resolved.

Take a look at this Technical Article from Wayne:
http://www.pelicanparts.com/techarticles/911_clutch_cable/911_clutch_cable.htm

And let us know how it goes.

[JJ 911SC]

Jonathan

Thanks for the posting. I got an 1983 Cab that was updated with a 3.2L and an 915/73 Transmission and sure enough the 2nd Gear has a tendency to grind...

So I'll get to it on the week-end. Which Adjustment instruction did you use?

Cheers

J.J.

http://www.pelicanparts.com/gallery/JJ_911SC

[jcsjcs]

J.J.

I can't remember what I used the first time around for adjusting the coupling - but this time I just winged it!

NOTE: My shift boot is off - so I can really see what is going on with the shift lever.

Here is an article someone wrote that seems to align (no pun intended) with what I did this weekend. It's easier than you might expect and the results are immediate. Keep a couple of wrenches in the car and a philips head so you can re-adjust if you find you got it wrong during the test drive.

http://www.pelicanparts.com/techarticles/911_shifting_improvements/911_shifting_improvements.htm

Also suggest that you consider replacing the Shift Cable & Helper spring if you clutch is heavy.

http://www.pelicanparts.com/techarticles/911_clutch_cable/911_clutch_cable.htm

[JJ 911SC]

Jonathan

Thanks, I'll check the links and the Bentley book.

I'll keep you posted.

Cheers

J.J.