Need help on a recent 915 rebuild as its a disaster

[ReconTrojan]

Background is my 86 911 had a recent engine refresh, new clutch and cable after purchase. I noticed after purchase that I couldn't shift into first constantly. We chalked it up to bad clutch and cable.

That was all replaced, adjusted and a WEVO shifter installed.

It still had problems shifting into first. Maybe 5/10 times, if i raved it I could usually get it in gear. No funny noises or anything. Just first gear.

Well I just didn't like it and decided to have the gearbox rebuilt, not refreshed but rebuilt. I had synchro's replaced, sliders , bearing etc etc. In addition we added the WEVO gate shifter installed.

Today the shop called me and said to come get it but warned me I may need to put some miles on it as it needs to be warmed up and broken in as its difficult to get into first gear.

WTF That was what I was looking to solve. I was not happy. Not only first gear but second gear is hard to find now. Plus its making a weird almost tractor sound ( constant) when I disengage the clutch that it did not do before.

Its going back tomorrow and they are calling WEVO and others to get advice of where to search for the problem. But just about everything that can be replaced has been..in fact everything. Does anyone thing the WEVO parts could be the problem?

Any advice would be appreciated and welcomed.


thank you

[winders]

What oil is in it?

[ReconTrojan]

Total 75/90 non-synth

[jlex]

What did the replaced parts look like?

[puddy]

Sorry to hear this, thats majorly frustrating i'm sure. I assume you also changed all bushings that could be worn? When I changed my well worn bushing at the shift coupler it made a big difference to how my car shifted. Also getting the shift coupler adjusted correctly takes some patience and is worth the time investment.

[Iciclehead]

Ditto on the bushings, 915's are also sensitive to shift lever alignment so make sure that is spot on (procedure on Pelican) and also make sure your clutch adjustment completely disengages the clutch....any spin from the clutch and shifting will be a grindy process....

Dennis

[ReconTrojan]

The replacement parts actually looked very good. They felt at some point it had been refreshed. Only the first gear had worn dog teeth and the 2/3 slider I believe was a little worn. All replaced of course.

I will inquiry about the bushings today.

[lelix]

Lots of things to check for.
- Before questioning internals, All Bushings, coupler adjustment etc are very important
-Correct asymmetrical/asymmetrical sleeve/dog teeth on first gear?
-Correct symmetrical/symmetrical sleeve/dog teeth on second gear?
-Correct installed width of the synchros?
-Correct adjustment of the internal shift forks in conjunction with the WEVO?
I've installed the WEVO gateshift during my rebuild, it requires a precise adjustment with the internal shift forks to function properly and not bind, once adjusted though, it should be trouble free and direct.

Are you having trouble getting in and out of gear with the car off?

re: Tractor sound with the clutch disengaged, you may be hearing the backlash in the gear clusters.
Was the throwout bearing replaced?

[Cairo94507]

Does the shop doing the work see 915's all of the time? Or is this a relatively rare transaxle for them to work on?

[ReconTrojan]

Thank you, all of these will be asked today.

[Elombard]

Note the adjustment procedure for a Wevo is completely different than for stock shifter. Its actually easier, I second the above comment - do they work on many 915s? If they are an air cooled Porsche shop they do.

I have heard that the Wevo internal gate shifter makes the shifting extremely positive. Some people dont love it. I have not tried it but I will some day.

[cmcfaul]

Racers will sometimes use a 2nd gear synchro in first as 1st gear synchros are designed to only engage when the car is stopped.

Not sure how long you have owned your car but much of what you described is normal. Just the idiosyncrasies of the 915 gear box. If it won't go into 1st gear. let the clutch out and push it back in. works 90% of the time. If not, repeat. Gets easier over time

Make sure your linkage is all tight and in good shape. The ball and cup at the bottom of the gear shifter is first place to check. The linkage at the back of the tunnel is the second.

Chris

[DanielDudley]

If the input shaft on the transmission is dragging in the pilot bearing or bushing in the crankshaft, you will also have problems getting into gear, similar to having a clutch that does not disengage fully when depressed. I also seem to remember reading that the lay shaft in 915 transmissions can get bent, meaning that the shaft is not straight. The guys who really know 915 transmissions will check for this, and they can be straightened without being replaced.

Two problems not commonly covered in a rebuild. However, maybe you should have the car driven by someone who knows these cars for an opinion ? I have some other brand of gated shifter in my 911, and it can feel tight going into second, but it is not the transmission.

I will never have a ''money shift'' with this set up, but I personally prefer a loosey goosey factory assembly. PO wanted this unit, and I have gotten used to it.

I had a 928 Transmission one time that I switched to Redline NS because it shifted poorly after a rebuild. NS allows a higher coefficient of friction in the syncros. Others prefer Kendall, and some day that the Swepco often used in these boxes makes for hard shifting.

That was certainly my experience in the 928, and in one other Porsche with Porsche style syncros.

Bottom line, check your oil first, and if you have a short shift kit, remove it and go back to long throw. A short shift kit always decreases mechanical advantage of the shift lever. Some people ascribe to the KISS theory, ( Keep it Simple, Simon) but I recommend doing the simple stuff first. (SSF) That means the above, and then checking the input shaft and pilot First, if you pull the engine/transmission. Do these things before you do another tear down. Also closely inspect the clutch.

Sometimes it isn't all one thing, but a few little things together that add up. But also consider that these trannys don't want to be shifted quickly at lower RPMs, but need to be shifted in a timely manner, in a rhythm. When shifting from first to second, try running it up to 4000 RPM in first, and then when you shift, hold the stick firmly but lightly, and pull it quickly up to second gear, until you feel resistance. when the internals of the transmission get to a happy speed, you will feel the stick want to fall into second, and it will with very little assistance.

Like I intimated, there was never anything wrong with my 928 box. It was a combination of the wrong fluid, a short shift lever, and improper technique. However, after all that, if your transmission does not respond, sent it out to one of the really good pros recommended by people here at Pelican. Simple parts replacement won't always cut it.

[Tom '74 911]

Originally Posted by puddy

Sorry to hear this, thats majorly frustrating i'm sure. I assume you also changed all bushings that could be worn? When I changed my well worn bushing at the shift coupler it made a big difference to how my car shifted. Also getting the shift coupler adjusted correctly takes some patience and is worth the time investment.

Others have mentioned the shift bushings, coupler bushings and coupler adjustment already, but I thought I'm emphasizing them again as they deserve consideration. I had my 915 rebuilt this past winter and it has taken a lot of fiddling with the shift coupler adjustment - far more than I expected - to get it shifting correctly. A spline or two in either direction makes a difference in my experience.

Verify the bushings are all 100% and that the coupler is adjusted correctly, then look to the internals of the transmission...

[rbogh901]

Originally Posted by Tom '74 911

I had my 915 rebuilt this past winter and it has taken a lot of fiddling with the shift coupler adjustment - far more than I expected - to get it shifting correctly. A spline or two in either direction makes a difference in my experience.

Verify the bushings are all 100% and that the coupler is adjusted correctly...

What method worked best for you?

[Steve@Rennsport]

Did the shop use a lot of Rausch & Spiegel parts????

If so, precisely which ones??

[john walker's workshop]

Wevo makes some good stuff, but with the internal shift gate, it just don't feel like a normal, nice shifting 915 anymore. Very notchey. Race car stuff IMHO.

[ReconTrojan]

Thank you all- much appreciated.

Its getting torn down again, I will report back the findings. At this point we may lose the WEVO gate shifter. My goal is simple, find the gears without pulling the knob off in the process. Today 1st, 2nd and Reverse were near impossible on my way to the shop.

[Tom '74 911]

Originally Posted by rbogh901

What method worked best for you?

I had some marks I'd made on the shift coupler (mine's a WEVO) previously that I used as a starting point. I essentially used this method though too: Porsche 911 Shifting Improvements | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article

Between the existing marks and the standard adjustment method, I was able to get the car drivable & close. Then it's just a matter of small tweaks to get it 100%.

I also have a Seine Systems gate shift kit, which I personally like a lot. Finally, as part of the transmission rebuild & reinstall, I also installed a factory short shift kit. I was never able to get it to feel quite right so I ended up uninstalling it and reverting back to the standard shifter with the Seine Systems gate shift kit.

[jibmaster1]

I had a 85' 911/915 tranny a few years back that I ended up pulling the engine on to replace some of the usual leaky oil culprits, the rear main seal, new clutch etc. At the time I looked at the clutch release fork that slots into the throwout bearing and told myself "ah, it looks fine". I had also replaced the coupler with new bushings, new clutch spring, cable, adjusted it to spec, etc. when I was putting it back in. After it was back together it shifted fine for a few days and then I noticed it seemed harder to shift into first-insidiously though over days. I went back under, adjusted it again and it shifted fine for a few days before yet again it started becoming more difficult to shift into first! Well, finally after playing this game for the next month and feeling like I was taking crazy pills I finally heard the throwout bearing start squealing constantly. Frustrated I ended up pulling the engine BACK out (took about 2hrs this round!), and sure enough, the shift fork was bent and cracked and the throwout bearing was toast! So, I ask: did you replace the shift fork and throwout bearing when you had the trans work done? I read your post and it just seemed a little suspiciously similar to what I went through. Good luck man. I'd be curious to find out what you found.