901 Trans Rebuild-While the engines out

[Sean_irl]

Hi All.....my engines still out after my infamous blown cylinder. But the good news is i'm making good progress and hope to have all the parts sourced in the next two weeks. Then its fix time and put the baby back where she belongs. Man its been a long time....but my learning has increased massivly

So, while the engines out i'm thinking of sorting out the 901 transmission. The issue here was changing up or down into 2nd gear. If I changed over 2k RPM there was a serious crunching noise......methinks its the synchro.

So heres my new query. Is it easy to change the synchros without any expertise and specialised tools. I have the Porshce WS manual for reference.

What do you think?

Thanks,
Sean

[jtf914]

Hey Sean,

The 914 also utilized the 901 transaxle. Red-Beard wrote a great rebuild article on the 901. Check out his website: Red-Beard

-Justin

[red-beard]

The main thing you need are the diagrams...and those are in the article.

[Grady Clay]

red-beard; Great article on 914/901 rebuild. Please e-mail me at gradyclay@hotmail.com and I'll offer 2c.

sean; What year is your 911? Do you know how many miles, history? What is the transmission type? (901/?? or 911/?? In the next day or so I'll come up with some recomendations for you. Carefully read red-beard's article. Print out a copy and start yourself a hardcopy notebook. Add photocopies of the factory workshop manual section, the parts manual section, and everything else you find. You will want to keep notes and photographs of YOUR transmission.
It would be unlikely that after 30+ years that someone had not been inside the transmission. You want to know how it's supposed to be, not necessairly how it possibly was incorrectly reassembled at some prior repair.

All; Who knows the other best posts/sites for transmission rebuilding? Sean could use that info also.

Best,
Grady

[Sean_irl]

Everyone..thanks for the replys.

Red Beard, i've printed out your article and am reading it carefully. Its a great starting point....a major help getting up the curve. Thanks.

Grady, it a 1971 2.2S... I don't have the transmisson number handy. But its correct for that year. I've history for the car since 1986 and there is no mention of any tranny work. Again reference photos are best here as i'll be struggling to identify whats good or bad without them. Redbeards article is good hear...I need to read again and again.

Thanks again,

Sean

[red-beard]

One thing to note, in my article, you are not removing the differential. It really is a how to remove the gear stack only from a 914.

The rest of a full rebuild is replacing the rest of the seals and the large side seal o-ring.

[Sean_irl]

Red Beard...thanks for that point and update. Tonights reading is the schematics :-)

[Grady Clay]

Sean,
For 1971 the transmission serial number and type number are on a raised area of the casting under the differential.

First let me first address some external issues.
You will need to clean, inspect, replace the clutch cable, the plastic piece at the transmission, the pivot piece at the clutch arm and the plastic hemisphere in the clutch arm. Your car should have the up-dated pivot for the clutch arm.
Inspect the loop on the transmission differential side cover for wear. If damaged it can be repaired with an insert.
The clutch release bearing guide tube should be modified by grinding a small drain grove in the flange. The purpose of this is to provide a safe path for any transmission oil that should leak past the input-shaft seal. Additionally you should add a seal inside the guide tube to act as a “dam” for transmission oil coming past the input-shaft seal. All this helps prevent gear lube from damaging the clutch disc.
You will want to remove the axles and clean and re-lube the CV joints. You will need new CV gaskets (4). I would recommend new axle boots (4), clamps (8), and new Skorr washers (16) under the CV bolts. Carefully inspect the CVs and the bolts. When you take the axles out, put the stub-axles back in the hubs and torque them (at the wheels) if the car is going to be on the ground, otherwise the rear wheel bearings can be damaged.

Follow the workshop manual for transmission removal. I would remove the engine and transmission as a unit unless you already have the engine out.

Once the transmission is out of the car, you want to get externally perfectly clean! Red-beard is absolutely correct. The transmission was originally covered with a Valvoline product “Tectyl” that is basically cosmoline. It comes off with Stoddard solvent but after 32 years it will take some elbow grease. After reassembly, you should re-apply this coating to prevent corrosion. More about that later.

Don’t get the starter soaked in solvent, it doesn’t like dirt, oil and solvent inside. There are two starter motors available; a 0.8 HP and a 1.5 HP. It says on the side of the starter. Hopefully you have the 1.5, if not, I recommend exchanging for one.

Are the rubber boots at the shifter, clutch cable, back-up light switch, starter cable, and speedometer drive all in good condition? If not get them ordered now as some may be difficult to find.

Get the transmission warm inside and then drain the oil. Carefully inspect the magnetic drain plug for ferrous material and transmission parts. Clean the external surfaces again. Upon reassembly, one grain of sand in the gears can do a lot of damage. Now is the time to get it perfectly clean.

Follow red-beard's advice about soaking the fasteners with some penetrating fluid for several days.

Please be careful with all these solvents around. We don't want to visit you in a burn ward or worse.

More to come.

Best,
Grady

[Grady Clay]

Dumb o’l me.
I forgot the accelerator bell-crank on the side of the intermediate plate. You should remove the plastic bushings and inspect everything. Replace or reinstall as appropriate. Lube with light oil/grease. You should inspect the throttle link that goes up to the engine. Where it connects to the bell-crank is a major ware point. You should replace the rubber throttle coupling toward the chassis and inspect/replace the rubber boot. The entire throttle linkage system is a whole separate issue.

More to come.


Best,
Grady

[Grady Clay]

Sean,
It's Friday. What is your report?
Best,
Grady

[Randy Webb]

Grady, Red Beard, et al. - I don't want to hijack the thread, but can anyone tell me when the 901 (or 911) transmission changed from haveing CV joint mating surfaces on the stub axles that are flanged, to ones that are flat (like the later 915 trans.)? Thx in advance!

[Grady Clay]

Randy,
It was the '69 model year.
Generally speaking, '65-6 had Nadella axles, '67-8 had the smaller 6-bolt Lobro, '69 went to a longer axle (to acomodate the axle being angled back for the longer WB) with a large 4-bolt, 2-roll pin Lobro CV. Generally '69-'73 are all the same and use a CV gasket. I think? '74 was when they went back to a smaller diameter Lobro CV.
Of course there are exceptions. A '69 when ordered with a LSD came with an Aluminum casting and Nadella axles. A '75 930 had the larger CV, etc.

The axle flange at the transmission will interchange all through 911 and 915 but the offset toward the CV is different among dozens of different flanges.

If I'm wrong, someone please correct me.
Best,
Grady

[Sean_irl]

Grady, Red Bear and all....

Thanks again for the input. The transmisson will be done....but after the engine rebuild. My worst scenario has kicked in and my conrod is bent...so its all bets off and a full and complete tear down of the engine will commence asap.

Sean

__________________
1971 911S

[Grady Clay]

Sean,

Sorry to here that. Do you have your engine story on another forum/thread? If so, where. Perhaps you can get more Pelican help.

Good luck,
Grady

[Sean_irl]

Grady....

***Lost the porsche lottery (long)***

just updated it very recently with the latest news.

Sean
_______________
1971 2.2S