Jim K.

Fellow 911 family, I need your help and advice. I picked up my 1983 911SC with 127k miles from my dealer about two weeks ago. I had them do a full service including changing my transmission fluid with Mobil1 Mobilube PTX 75w-90. I drove it home and things were fine. A couple of days later I took it for a 10 mile drive and noticed the downshift from 3rd to 2nd was a struggle with a slight grind. I figured maybe I "was off" and didn't think much of it. Well, from 5th to 4th grind hard as well. I had to feather it in, something I never had to do. I went home and let it sit. Took it out again, same thing. I decided to go to my local independent shop today and the owner took it for a drive, said I need new synchros. Quoted me $3200 for synchros, sliders (?), teeth and a few other items. Basically, almost a full rebuild. I hit pause and called my dealer.

My dealership said he will look into it. My concern/question is could the new fluid have caused all of this? I requested SWEPCO 201 but they put in Porsche approved Mobilube. I looked it up on Suncoast and it states it is to be used for manual transmission cars from 1965-2012. I believe it is synthetic. This seems so ironic. This fees like one of those cliches where I should have left well enough alone. I tried to do the right thing and stay up on maintenance.

Now, here is where it gets real bad. This evening, on my way home from the independent shop, about 12 miles in, I struggled to get it into 2nd gear. I had to push it in hard. Then at the next traffic light, I could not place it into first! When I did, I gave it throttle and it stalled! I got a smell of sulphur, almost like from fireworks. I got it into first but it did not want to go! I placed it into 3rd and was able to get it home. I was sweating from stress and frustration. The whole thing feels like it is imploding and all so fast! All of the above is within 75 miles since getting the car back.

It is now in the garage. I will have to tow it to the dealership.

What are your thoughts? I had ZERO signs of tranny issues until now. All a coincidence? Was the old fluid masking these issues?

I appreciate your thought and for reading my post!

Mark Salvetti

Hi Jim. The usual advice for the 915 gearbox in your car is not to use synthetic. It is too slippery for the old-style syncros. I am not surprised your dealer didn't have Swepco, they probably almost never service the older cars.

But having said that, a few miles with synthetic is not going to ruin a gearbox. I'm wondering if your real problem is that the shift coupler has come loose (under the access door on the floor in front of the rear seats), or you have clutch problems.

If your gearbox has never been rebuilt, I'm sure you do need new syncros, but to me the sudden onset of severe issues like these is likely something else.

Not sure about the repair pricing, but the parts sound right. You need to replace all the worn parts, but they won't know for sure until they get inside. You do want to replace the sliders with the syncros, and the worn syncros usually wear the dog teeth, at least on gears 1-3. If they get inside and find worn bearings or loose bearing races, the price will go up.

Mark

emac911

Did they actually fill the tranny with oil? I think I would check the fluid level first

theiceman

a few things ..

I think Mark might be right and your shift coupler has imploded from you trying to force it into gear. check that ... and the other linkages and bushings under the shifter assembly. i can see the wrong fluid not destroyomng the gear box, but definitely being damaged by forcing it.

Smell of sulpher is almost always alternator over charging and boiling the battery. causing acid to spill out into the front of your car... if this is the case you need to completely wash out the front of that car , even just run a hose in the battery area and let it all pour out or the acid will destroy the front of that car from the inside.
lots of info on this.

ErrorMargin

I agree with the others here. Check/replace all the shifter bushings and replace the fluid with Swepco 201.

There are three shifter bushing to replace, make sure you replace them all. https://blog.fcpeuro.com/how-to-repl...ed-porsche-911

76FJ55

What is the condition and adjustment of your clutch cable? if the clutch isn't disengaging correctly during shifts you can get significant grinding. The issue with pulling away from a stop in first is concerning though, but as others have stated if your coupler is going, you may or may not have actually been in first.

Jim K.

Members...thank you for the replies. Here is an update and some answers to the questions posed above:
1. No gearbox work since I have owned the car for 24 years.
2. The clutch was replaced a few months before I purchased it in 1998, approx. 107k miles, I believe.
3. I believe the smell coming from the car is of the clutch "burning" due to stress; I checked the batter, all good! Nice direction though!
4. The dealer did change the fluid. They used the Porsche recommended fluid which boggles me since it is synthetic and the general consensus is not to. Why would Porsche say it is Ok? I am asking for SWEPCO when they pick it up.
5. I will direct my dealer to look at the bushings...

My service manager from Porsche came over today to assess. Yes, very nice of him to do so. He feels it is the linkage. He drove it and when it goes into first he feels it is not first, maybe third gear. He has to give it a lot of throttle to get it going, basically what I experienced, hence the burns of the clutch. He feels the gearbox is ok, just a linkage issue. YOUR THOUGHTS? All a coincidence?

Should I install a Porsche short shift kit while this work is being performed? Worth the cost/benefit?

I will have it towed this week and update the thread once again...I look forward to your thoughts as well.

Thank you!

Bill Verburg

Certainly Swepco is the product preferred by the vast majority of owners, I can attest to the fact that syn doesn't work well in a 915, I tried it for a week and immediately went back to Swepco

besides the bushes causing shifting issues an often overlooked weak link is the clamp

I had to replace mine w/ this Wevo part

Mark Salvetti

Hey Jim, sounds like you are closer to a fix. There is some trial and error to adjusting the shift coupler, although it could be that the plastic bushings crumbled. This happens in older cars, and it throws off the adjustment. Easy fix.

I don't think the short shifter is recommended for the 915. The throws will be shorter, but it will require more effort. Also, if you move the lever at the same speed as before, your shift will be a bit quicker. But the 915 doesn't like to be rushed, so I think it can be argued that if you do shift faster, the syncros have less time to do their job and it can lead to more wear.

In a race car, you want faster shifting, and gearbox rebuilds come with the territory. But probably not what you want in a street car.

If the current throw is too long for you to be comfortable, then the short shifter may make the car more enjoyable to drive. No doubt some people love the short shift kit. Just try not to rush the shifts.

If you think the shifting it too vague, there are other fixes. Make sure all the bushings in the shift mechanism are new, and look at the Wevo or RennShift products.

Mark

rstarga

Hard to understand why a dealership would use synthetic in a 915.
As stated above check all the bushings and change to Swepco.
I have had the factory short shift kit in for years and like it much better than the original long throw.
Have you always serviced the car at that dealership? Same mechanics or new guys?

ErrorMargin

Question for you: when the transmission is in gear (in any gear), how much play is in the shifter? Meaning, how much can you move the shifter left and right when the transmission is in gear?

If it can move more than 1/4 inch, then your shift coupler bushings are shot and must be replaced.

There are three bushings in the linkage, make sure they replace all three.
1. Coupler bushings
2. Rod bushing
3. Shifter to rod bushing

A kit with all the bushings is less than $16 from Pelican: https://www.pelicanparts.com/More_In...=PEL-BUSHKIT1N

One point to consider is that the coupler bushings will wear out and need to be replaced again. When they are first replaced, you will be amazed at how nice and precise the shifting is...but then over time it gets looser until you reach the point you have now reached and you can't shift well. You might consider installing an aftermarket shift coupler that will not wear out and has no play at all. These are more expensive, but then you will never have to worry about the coupler bushings again and your shift linkage will always be precise. Something like this: https://www.pelicanparts.com/More_In...?pn=WVO-PSJ-S2

I would go with the aftermarket coupler above before I went with a short shift kit.

The short shift kits are nice, some people love them. I've driven cars with them and I've decided it was not worth it for me.

That said, if I was going to get a short shift kit, I think the Wevo is the one to get and I would get their shift coupler along with it.: https://www.wevo.com/Products/Shifte...ter-915All.htm

theiceman

ah yes ,, clutch burn has its own smell , certainly not Sulphur ... im surpised by now you not unscrewed the cover between the 2 rear seats .. it will be obvious in 5 minutes ( 4 screws and a cover) if it its the coupler.

Jim K.

When the transmission is in gear there is play, a decent amount. It has been like this for years.
Also, when I asked the dealer about Mobilube, they stated it is approved by Porsche for this model range and said what matters is the viscosity. I agree with all of you re: Swepco.
The car will be in their possession once I return from vacation, I will have it towed to be safe.

I will update everyone once they get in there per your suggestions. I plan on printing this thread and giving it to my service manager to help the tech figure it all out.
I feel positive about it--meaning my transmission may not be total shot--based on what the input you have provide.
I thank you all!

F1LOCO

When I picked up my SC a few months back, I was unhappy with the shift and more than the usual sluggish 1st to 2nd gear change. Picked up Stomski's kit including front bushings and new clamp. Couldn't be happier. Dialed it in on the second attempt. I had fiddled with the old coupler countless times before biting the bullet. I'd gain in one gear shift and lose in two others.

https://www.stomskiracing.com/produc...20608042926123

Dr. 914

I agree, sounds like they forgot to fill it, just drained it instead