Shafted twice on transmissions. Should I stay or should I go?
 

A bit of a rant today but I think I need to get this out of my system.

I make a pretty modest living but Porsche ownership has been my biggest dream since childhood. There was a cheap 74 911 that I purchased a year ago - you may have seen my build thread on it so far.

I knew there would be issues with it - so I have done the best I have to fix everything myself since I have worked on cars for a long time. So far the car has been a challenge - since I come form the world of Japanese cars where everything is cheap, easy to work on, and reliable. No headstand problems. No valve guide issues. No broken clutch forks. Some people might call this the "charm" of the car heh.

http://i.imgur.com/3j4i7a8.jpg?1

When I had my first drive, I took it around the block. The PO told me that the engine and trans were in very good condition. He even drove me around in both. I changed the engine oil once I got back. The transmission oil I was going to do the next day, but I took it out around the block this summer for a total of 10 minutes - big mistake.

Transmission made a pretty bad BANG - I lost all gears except for 3rd. I limped home and drained the oil - nearly nothing came out. My current assumption is that the 3rd gear overheated and welded onto the input shaft. Currently i haven't taken it apart yet. Someone had to have drained it and not filled it back up.

So eager to get it on the road again, I scour on Pelican to find a used trans. Found one 6 hours away from me. Hop in my daily and do the 10 hour trip. 3 days later and 2500$ after I got a what the owner said was a "good" transmission. The seller never installed it onto a car so he didn't know. He showed me the email of the previous owner (a shop from the states) and he was the one who said it was a solid shifting trans. I trusted him.

Pulled a few all nighters to Remove my old trans and bolt up the new one. I noticed the shaft is very stiff to shift but hey - maybe its just tight because it is in better condition than my old one. Once I bolted up the shifter I knew there was an issue. I needed 2 hands to put it into any gear. Filled it with 80-90 and I took it out for a spin. Makes very weird grinding noises during operation. So someone wasn't honest about the condition. Just my luck.

Currently the car sits in the garage with the new broken trans. So my childhood dream has turned into a complete nightmare. My Plan is to take it apart again and rebuild it myself. One of my friends told me to just sell the car and move on. I also thought of taking it to a shop to rebuild. Another 2-3 grand would be thrown at that. At this point I am pretty devastated. One of those "never meet your heros" kind of deals.

Even if I end up fixing the car. I think its already made an impression that Porsche ownership just isn't for me. Or maybe this car just hates me.

Rant over. What do you think I should do at this point?

Drain your trans oil and examine/photo your drain plug magnet - that might reveal what the problem might be. Are you positive that your install is correct? Is it possible that the floor of the car under the center tunnel is bent/damaged; possibly pinching the shift rod?

IMO, you've answered your own question--air cooled Porsche ownership is not for you.

As you've stated, these cars will constantly need attention, parts are relatively expensive, and expertise beyond the DIY level will come at a premium price. Sorry to say, but you made two very large mistakes at the outset by taking sellers at their word. The cost to you was not only monetary, but it has killed your enthusiasm for what might be a very fun and enjoyable vintage 911. Note the word enthusiasm. That is the key. If you are not enthused about the car, you do not belong in the ownership category. These cars are a labor of love, emphasis on labor.

Take a break and reassess your position. We know little about the car except what you've disclosed in the OP. A solid, rust-free '74, can be a terrific car. The tranny issue can be resolved with money. If you cannot restore your enthusiasm when the car is up and running, you should sell because you will always need to spend time and money to keep it running and enjoying the experience. If you have major issues now, like rust issues to address or engine issues (you never mentioned if there was an inspection of the engine by a pro, but I assume not), it might be time to let it go. Maybe you are still lodged in the Japanese car "house." If so, you need to "move out" and understand you are now in a completely different realm.

Checked that area over and over. No issues there, completely wide open. I will drain the oil when i pull it next and check. Even when I purchased the trans, and had it on the bench I remember it being very stiff. I called a few of the local shops afterwards and said you should be able to shift it no problem with your bare hands. So perhaps a bent shift shaft is the reason.

Another issue is going side to side in neutral. when you push into 5th/reverse its very notchy. Looking at my old transmission, it would make sense that if the shaft is bent the little square tab isn't fitting into the slot for 5th/reverse nicely.

Just my observation.

I think you hit the nail on the head with this one. Just hard to swallow sometimes dreams are better left at that. I think i would be in a constant state of fear driving the car. Knowing if a valve dropped or something, it would cost an arm and a leg to have it rebuilt, even if it was myself. I think enthusiasm is important. And I feel burnt out.

I hear you! I've recently returned to air cooled Porsches after years playing with Porsche water-pumpers. After almost 15 years, I decided to re-focus my attention on the '76 sitting in the corner of my garage that needs an engine. I can't believe how things have changed since the early 2000s. Pelican has grown, the air-cooled "scene" has shifted... and the prices. :eek: They are obscene!

As a life-long Porsche fan (and a frugal business person), I'm having doubts on whether I can reasonably justify the costs involved to own, maintain and run an air-cooled 911 today. That said, they are incredible cars to own, and the road to get the car in your garage fully sorted once you've purchased it is a very long, winding, undulating one.

Whether you want to take that rode is for you to decide. Good luck!

Sorry to hear of your misfortune. Hopefully you can recover from it OK. The cars are too much fun to let a few crooks chase you away from them. My recomendation would be to slowly and methodically tear your old transmission down, and figure out what went wrong. Transmissions are not difficult to repair. They are a little intimidating, but just because they are unfamiliar to most people.

I have to agree with Dave. Fear compounds when something is unknown or unfamiliar. You have two transmissions--tear into one and see how straightforward it can actually be! You have nothing to lose and a good knowledge to gain. I'd even wager that it will help you develop a connection with the car and give you the confidence to tackle other things that go wrong...

It might even rekindle your enthusiasm.

Did you take the inspection plate off the first gearbox. Could just be the little two prong fork that guides the main shift rod. Gearbox number one could be less than a $100 fix.

I just got through rebuilding my 915 after breaking 2nd gear. If you can pull and reinstall the transmission, you should have enough mechanical aptitude to open your transmission up, inspect and recondition it. I looked at the transmission tutorial until I was blue in the face before starting on Mine. It was much easier than I thought it would be. BTW, I just replaced what I needed to replace, and it still cost me over $1200

Take a step back and take a breather.

It seems like you haven't fully enjoyed the car yet. You can't fall in love until you know it's personality. And let me tell you smiles per hour is endless.

You will have kinks and bumps but as you smooth it out you will have car that's amazing and you know it's done right.

Regardless you will need to fix it and sell it or take a hit with a bad transmission.

Preface

I'm a new 76 911 owner and I had tons of buyers remorse after it came home. It's just necessary for me to own but I've wanted one my whole life. So I just kept driving it and driving it as much as possible. It's only been a few weeks and I've basically been daily driving it and for any reason possible and I sit it and night and just take it in It's now in the shop to get some prior bugs worked out and I miss it like its one of my kids.

Thanks for everyones encouraging messages. Lit a fire under my ass. Since I just finished pulling and installing - seems like I have to process down pretty fast if I hustle. Transmission is officially out again. 1 hour and 14 minutes! Still had all my tools out from last time so made it super easy.

http://i.imgur.com/eUhhjEb.jpg

So I have my old one to compare and see whats wrong. Ill post some pictures once I get the tail section removed - will appreciate any help!

That was quick :D

Good for you, Jeffrey! Wasting NO time!

Rule of thumb - if it's out of the car and seller doesn't have a detailed build or repair receipt, it's a core.

Ran when parked, worked when pulled, LOL.

Jefferey, pull the plate before the tail cone!

Okay so pulled the top cones off. Played around with the shifters and such. I think I found the area where it is binding.

So this picture is of where the shaft exits the trans. This is of the transmission I just got with the binding issue. It is a 915/61 from 1977. But someone has been in here before because the midcase is aluminum...
http://i.imgur.com/oar3gr0.jpg?1

This is of my old trans that is blown. But the shaft shifts fine. its a 915/02 from 1972. Notice the bearing.
http://i.imgur.com/j02paBO.jpg

So this bearing make it shift way smoother. but the one without the bearing is a snug fit against the case. So I think it was a design change? Regardless. I tried slipping the one with the bearing over my other trans and it glides much better. i can shift it with my hand.

Anyone make sense of any of this?

Cheers,
Jeff

great looking car....definitely worth keeping and getting that trans taken care of.
You are in an even better place than most, cause you have 2 transmissions. Just open them both up and use the best parts from each to rebuild!

Thats the plan!

Also check out these two forks. One is like off centered. not sure if this would actually affect anything though. Anyone seen something like this before? Probably swap over to the straighter one. But I don't think thats the cause of my problems.
http://i.imgur.com/cI7wqFP.jpg?1

http://i.imgur.com/YF1mUaF.jpg

Don't bail out. You got a bad apple. These cars can be very trouble free.
Stay the course!

Thats what I've been saying! Search here. There are many threads about fixing it. That may be the only thing wrong with gearbox number one. You may be able to bolt on the plate from gearbox two and be fixed.

In my experience, a bad transmission is relatively easy for someone with your level of wrenching ability. good luck. It's fixable.

The two gearbox thing (one working one, one reference one) is working out already. You can be our new gearbox expert :D

Good luck with the plate swap.

That is what Matt was trying to tell you about.

You have a great opportunity here to end up with basically a new transmission.

BUT, TAKE YOUR TIME AND SPEND SOME TIME READING AND LEARNING. These transmissions have some unique features and take some special tools. If done right you will have a bullet proof, great shifting, long lasting transmission. Make a mistake and you are right back at square one.

Here is your homework. How-To: Porsche 915 Transmission Repair Tutorial Part 1 - Porsche Wiki

and http://forums.pelicanparts.com/porsche-911-technical-forum/853702-915-transmission-rebuild.html

Thanks Trackrash. I actually read that over for the heck of it a few weeks back. Good refresher for sure.

So heres the progress for the day. Started taking apart my original known blown trans.
http://i.imgur.com/rWyCl2g.jpg

So check this out. This is from my "new" trans. Midcase is aluminum on this one. found some ribs broken. So something must have happened before my ownership because I never dropped it or anything. Maybe this impact caused the entire case to warp? Which is why my shift rod is binding. Just an idea...

http://i.imgur.com/hBJSwHd.jpg

Its also a bit of an eye sore. So I planned to use the Magnesium midcase from my original trans.

http://i.imgur.com/V0szqeN.jpg
...But one of the bearings is spun. No play, Just turns. So I could loctite 660 it back in place. Not sure at this point.

So I haven't taken apart my newer trans yet. But here are some pictures through the shift fork hole.

2nd Gear:
http://i.imgur.com/VnwNv1g.jpg

3rd/4th gear:
http://i.imgur.com/LBnicOR.jpg

5th gear:
http://i.imgur.com/UQoxdNK.jpg

And thats all i got. Cant see 1st without taking off the midcase.

So I still don't know why my case is binding during shifts. Thats the big mystery. My plan was just to swap midcases and the selector shaft. But now the case has a spun bearing it makes my decision harder. Maybe once I take apart the other trans later on I will have a better idea...

Let me know your thoughts.

Did the rod give you any trouble when removing the tailcone on box #2? A common rookie error is to drop the engine/gearbox assembly with the rod still attached to the coupler. This bends the rod and makes it hang and bind on shifting like you describe.

Didn't you say you heard a loud bang? Maybe you hit something while driving?

General advice from someone who has only opened up one 915 box (1973 mag case).

You can leave the nut on the pinion shaft and parts wash it as a unit. Parts wash all pieces thoroughly.

Mounting the housing to an engine stand will make assembly/test shifting much easier than having your 915 on the floor or a bench. I did this alot before sealing mine back up.

Replace all seals and gaskets.Use Curil T on the gaskets.

The races in my case would turn and had no slop. I used loctite 640 sleeve retainer. It is a green liquid.

I removed the coupler. But I have suspicion that the rod is bent. It's the only real explanation. The rod didn't give me any trouble taking it off though just a bit stiff. Once I got the tailcone loose it slid off. But there's much more friction sliding it on and off compared to my tailcone from 72 since there's no bearing in the later one.

So perhaps that bearing can mask a bent shaft much easier which is why when I try that one, it seems to be much smoother.

I just don't understand why porsche would remove the bearings in the later models.

I wasn't suggesting you bent it. I'm suggesting that like many "ran when parked" gearboxes whomever pulled that box did it.

With the tsilcone off and both inspection plates removed you should be able to pull those rods. One the bench even a slight bend will be obvious.

Not sure why the bearing change. You will likely want to use the 74 one with mechanical Speedo. And front housing with 7:31 if its in Good shape. Unless your car is an electronic Speedo conversion. Not clear to me how you fitted the later gearbox?

I'm realy happy to see where this thread is going. Don't kid yourself Jeffrey, you are an airhead! I'm cheering for you.

Alex

Yeah its a bit confusing. The car is originally a mechanical speedo car. The new box is electric speedo, so I planned to just run the wires and convert it. I still have the mechanical speedo and cable right now though.

I can see that the shaft is slightly slightly bent at the end. Seems like it would be much more finicky if there is a slight bend and its being held in place through tightly fitting holes with near no-wiggle room or bearings.

Here is box #2 that is having the binding issues. Again the other side has no bearing. Just rides right on the magnesium case.
http://i.imgur.com/A4iD5kK.jpg?1

A closer look:
http://i.imgur.com/IMjLyek.jpg?1

Here is box #1.
http://i.imgur.com/ys3CJFl.jpg?1

http://i.imgur.com/JkWIHiL.jpg?1

If I put the shaft in, and cock it a bit then try and slide it, the one with the bearing will still slide with ease. but the one without will bind up and feel "sticky". Almost like it is galling.

Why would Porsche change to an inferior design? Really makes you wonder.

Also the midcase on Box 2 also has a spun bearing. Spun bearings for everyone! :eek:

Perhaps I could use the entire casing (bell housing, midcase and nosecone) from Box 1 and transfer the 8.31 gears over from Box 2. But then I would have to reshim the diff/pinion and thats really pushing the limits of how comfortable I am with this stuff.

Easy way out is to just swap shift rods and button it back up - hope for the best.

Always appreciate your ideas.

Just an idea here, but if you use the mid-case and diff case from Box 1, you can do some math and figure out how many shims to use with the Box 2 R&P.

Measure the total shim thickness of Box 1, and note the N-number etched on that pinion shaft. When you move the ring and pinion over from Box 2, compare that N-number to that from Box 1, and use the difference between N-numbers to adjust the total thickness of Box 1 shims.

You'll need to check how the gears mesh with gear marking compound after setting the pre-load and backlash of the ring gear. Which could require you playing around with more shims for the differential. Even if you move the diff bearings and shims from Box 1 to Box 2, you may find you'll still have to make adjustments.

Mark

Wow. No need to swap anything... found the problem.

Box 1
http://i.imgur.com/ajRbfbd.jpg

Box 2
http://i.imgur.com/kG9s6VP.jpg?1

Didn't notice it until I brought it to a glass surface. Severely bent upwards.

Thanks everyone for the support. Enthusiasm back to high!

Well done. Neither sounded catastrophic to me. Running it dry seems scary but based on the pictures there's only slight galling on the gears in box 1. Sounds like you are just going to move the rod over? The center cases can be repaired if you aren't looking to finish this today.

Very good trouble shooting. I just went through a similar issue. Had a 915/40 shipped to me and the shift rod got bent during transit. Got another shift rod and a tail housing (shift rod bearing surface was galled). Assembled and have had a happy couple of hundred miles since.

Well done, Jeffrey! Now bask in the feeling of accomplishment.

Thinking of getting it re-welded. Sadly I can't weld aluminum myself but I think its more cosmetic.

So heres part 2... this one might be a bit more difficult, and hopefully someone can chime in. When I had this trans in the car, it also made a slight noise like something was riding on the gear. I figured it was the shaft but now I am not so sure. take a look at the synchro ring hitting the three collar slide guides, sounded exactly like this when I was in the car too. I took a video:

https://www.youtube.com/watch?v=bOsuIT_jIsw

So maybe my trans is really fubard :eek:

Doesn't seem normal. Also it seems like leaving marks on the rings. Hmm..

Heres a photo of where it is hitting.

http://i.imgur.com/W0Gkm4k.jpg?1

Just when I thought I was in the clear. What could even cause the guides to hit? Or maybe it's normal and I'm going crazy? Heh.

No, those marks are normal. That's from the slider slipping on the synchro.

I'm not talking about the fins. That's cosmetic. I mean the spinning bearing races. I don't subscribe to the loctite solution. They need to be overbored and sleeved imo.

Just had my (4) bearing races bored and sleeved by CMS. You don't want to know how much.