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Now I am ready to focus on why I started this project in the first place. The transmisson.
I've never opened a 911 trans, so I'm not really sure what I'm looking at. Below are photos and I'd much appreciate any helpful descriptions.
Some things I noticed:
- Not a lot of fluid in the case < 1 quart for sure.
- Very very silvery colored fluid.
- The magnet was caked in slivery metal.
I took as many photos as I thought would be useful, but, I'm having a hard time telling what's worn... the symptoms were 4th making an awful racket when I engaged the clutch. Which is 4th gear below, and, how do I tell if something is wrong?
Trans opened up.
Very silvery fluid - not sure what to make of this...
If you are above avg DIY and only replacing the 3rd 4th syncro you can do the job without the heavy press. I just completed the same job on my race trans and have repaired many. Disassembly is not hard, But take pictures of the shift fork layout beforehand. Start by removing all the shift forks by removing the roll pins and the lockout plate.
Remove all the retaining bolts on the drive plate.
To remove the gear stacks heat the case by the pinion bearing and with a brass hammer drive the gear stacks out as a unit by "Tapping, Hammering" in the pinion gear and input shaft Its slow work but it will come out, Heat is your friend.
As far as I know, no one yet has devised a tool to get the front input shaft bearing off
and it has to come off to get the input shaft separated from the drive plate. I always sacrifice the bearing by cutting off the outer race with a cutoff wheel.
After the stacks are separated you can press the inner race, spacer and 3/4 syncro hub off by pressing from the 4th gear with a bearing splitter.
OP,
There are 2 or 3 epic threads on this task-one recent . That's all. Did you find them?
The skills and knowledge required are way beyond the average diy guy.
It would be wonderful if someone would video dgmark next time he rebuilds a transmission.AS time & miles accumulate ,the need for this work will grow.
As an add on 3/4 is the 1st gear set in the input shaft closest to the ring gear housing, Is your noise only when the gear is engaged or also in neutral?
If you are above avg DIY and only replacing the 3rd 4th syncro you can do the job without the heavy press. I just completed the same job on my race trans and have repaired many. Disassembly is not hard, But take pictures of the shift fork layout beforehand. Start by removing all the shift forks by removing the roll pins and the lockout plate.
Remove all the retaining bolts on the drive plate.
To remove the gear stacks heat the case by the pinion bearing and with a brass hammer drive the gear stacks out as a unit by "Tapping, Hammering" in the pinion gear and input shaft Its slow work but it will come out, Heat is your friend.
As far as I know, no one yet has devised a tool to get the front input shaft bearing off
and it has to come off to get the input shaft separated from the drive plate. I always sacrifice the bearing by cutting off the outer race with a cutoff wheel.
After the stacks are separated you can press the inner race, spacer and 3/4 syncro hub off by pressing from the 4th gear with a bearing splitter.
Reverse order to reassemble.
dgmark,
Thanks! I really appreciate you helping me with this really good info. I'm going to need all the help I can get
This job will definitely push my skill set, but, that's the point! How else does one build-up a skill set other than by doing?
Documenting the shift fork layout now and will remove the lockout plate tonight.
Regards,
Mike
Last edited by msteiner805; 03-24-2017 at 10:07 PM.
As an add on 3/4 is the 1st gear set in the input shaft closest to the ring gear housing, Is your noise only when the gear is engaged or also in neutral?
No noises in neutral. With the clutch pedal all the way in, I can get it into 4th, then, when I start letting off the clutch pedal (just barely starting to grip), the grinding gets pretty bad and the gear pops out.
OP,
There are 2 or 3 epic threads on this task-one recent . That's all. Did you find them?
The skills and knowledge required are way beyond the average diy guy.
It would be wonderful if someone would video dgmark next time he rebuilds a transmission.AS time & miles accumulate ,the need for this work will grow.
Hi,
Yes, I saw those threads, they're quite good.
There's even a pretty good video I found (not for a 996 trans, rather for a 930):
If it is not holding 4th gear it is either not engaging fully or not holding after engagement. My guess would be a problem with the Syncro hub as the synco ( Brass Portion) is out of the equation after the gear is engaged. Your probably going to have to replace the hub assembly but also change the 3rd fourth syncro rings when you are in there. Take a good look at the dog teeth attached to the gear and make shure none are missing, from what I can see in your picture they look good.
The hub is about $265. Syncros $140 each and the bearing about 275.
If it is not holding 4th gear it is either not engaging fully or not holding after engagement. My guess would be a problem with the Syncro hub as the synco ( Brass Portion) is out of the equation after the gear is engaged. Your probably going to have to replace the hub assembly but also change the 3rd fourth syncro rings when you are in there. Take a good look at the dog teeth attached to the gear and make shure none are missing, from what I can see in your picture they look good.
The hub is about $265. Syncros $140 each and the bearing about 275.
Thanks dgmark,
When you write "hub assembly", do you mean the part that is sandwiched by the 3rd and 4th syncro rings?
Start looking really closely at the shifting forks too. Compare them to each other and from one side to the other too. The one/s that look different will be the worn ones BUT you have a severely worn bearing in there that you haven't yet found. It will be obvious when you see it. Check the bearing races that stayed in the case too. The one that made the lots of noise will be in a really bad shape.
I've done a few transmissions before but not a 996 one yet. However, they all more or less work the same way.
03-24-2017, 06:24 PM
What am I looking at?
