Trany Question

[agabriel]

Hello,
I have an '86 911 Coupe that I just got for a decent price. I want to bring it around to be a fun quick driver that looks almost showroom, I won't be completely anal.

It seems that my first gear synchro is gone. I'm curious how much effort it would be to fix it. Do I need the tranny dropped or it can be fixed while on the lift? If it has to come down would it be better to trade it up for the g50 tranny? I have heard good things about it, but haven't driven it yet. Will this tear up other parts of the tranny if I just use it, or should I only shift into first at a dead stop? The car seems to pick up well on the roll in second.

Well I'm looking for info - any and all is appreciated.

Thanks,
Anthony

[jmohn]

First, a change to the G50 tranny is a major undertaking, involving a substantial investment, it's not a simple "swap" (do a search of the archives for additional info). Second, why do you think the first gear synchro is gone? If you're having trouble downshifting to first while moving, you should know that these transmissions are notoriously "intricate" to smoothly downshift into first gear, it may take a bit of double-clutching along with a proper "blip" on the throttle and a delicate feel on the shifter to make a nice downshift. While the first gear synchro may indeed be bad, I thought mine were at first, often, just learning how to make that shift will make all the difference. You have to find the "sweet spot", the proper combination of road speed, engine rpm, and feel on the shift lever to "ease" it down into first gear. You should also, probably before doing anything else, make sure the shift mechanism and clutch are both properly adjusted, and change the tranny lube (Swepco 201 is the accepted "lube of choice"). If, after all that, you still have problems, you can look into having the transmission rebuilt, and yes, it has to come out to be rebuilt.

Good luck,

Jerry M
'78 SC

[Jim Sims]

You have to remove (drop) the engine and transmission and take the transmission apart to replace first gear synchro hardware. I don't believe the G-50 is a drop in replacement. Jim

[agabriel]

Jerry,

Okay - this is my first Porsche. I have driven a few boxsters & 944s and although I like them, the 911 lines seem more pleasent to me. Back to the tranny...

Not always but sometimes when down shifting I get a slight grind. I don't force shifts so at the first bad noise it makes I give to neutral. I was reading the cars manual and it was saying at 39mph I should be able to shift into first. After everything warms up properly (actual driving warm up). So while I was reading the web sight for the 101 projects it mentioned the synchro as a possibility. This vehicle also has a brand new clutch and clutch cable and shifts excellent other that.

So after reading all of that if your telling me its not out of the ordinary to have to double clutch from time to time (not all the time) I leave it alone.

Thanks,
Anthony

[jmohn]

Quite right Anthony, the Boxster and the 944 (I had a 951 for a while) are both much "easier" to shift than your "new" coup. Also, notice in the manual that 36 MPH is the MAXIMUM (read, most difficult) speed at which you can downshift to first, I can't imagine why anyone would do this unless they were in an autocross or some other competition. I normally only downshift to first at about 15-20 MPH, and then only if I'm making an extremely tight corner and need to be going that slowly. If I'm coming to a complete stop (i.e. at a stop sign or light), I stop, then shift into first just before leaving the sign (or light). There's no point in using the (boyracer) downshift technique to slow the car, that's what brakes are for (and that car has extremely good brakes designed for the purpose). Downshifting to slow for corners looks cool in the movies but isn't actually very effective and puts added strain and wear on the transmission and clutch. Considering that, with a little experience, you'll be able to change the brake pads on your car in about an hour for as little as $80, but changing the clutch will take two days and cost about $500 (if you do it yourself, much more expensive in a shop), saving the clutch and tranny becomes paramount. Actually the "slight grind" you're experiencing doesn't sound abnormal for someone not experienced with this transmission, just keep practicing (you're right not to force it) and try blipping the throttle to raise the RPM's slightly as you make the downshift (helps to "match" the gear speeds and assist the synchros). In a few hundred miles you'll get "the feel" of it and by next year you'll be so comfortable with it you'll wonder why you ever thought it was a problem.

As a final thought, do check the adjustment on the clutch cable, new cables have been known to stretch slightly after use, which can throw-off the adjustment.

Good luck,

Jerry M
'78 SC

[s_wilwerding]

Originally posted by agabriel
I was reading the cars manual and it was saying at 39mph I should be able to shift into first.

Um, unless you have what's called an "active" transmission, I have never heard of anyone being able to downshift the car into first gear going 39 mph. My car has to be at almost a dead stop to downshift to first. Granted, my synchros are worn, but 39 mph seems really high.

[Gunter]

Make it a habit to go into first when almost at a stop, otherwise, you will get grind. The 915 is not good for fast shifting; give it a split second in neutral before going from one gear into another.

[widebody911]

Originally posted by s_wilwerding

I have never heard of anyone being able to downshift the car into first gear going 39 mph. My car has to be at almost a dead stop to downshift to first. Granted, my synchros are worn, but 39 mph seems really high.

I have a set of bent valves and dinged pistons who would like to disagree with you... This was from close to redline in 2nd, which is ~65-70MPH

[agabriel]

So I'll bring myself back to if it isn't broken don't fix it. Cool - I don't mind saving money for other things.

Thanks,
Anthony

[911nut]

Along with the aformentioned Swepco, replace the bushings in the shift linkage. There's two up close to the shifter and the coupling bushing in the tunnel between the rear seats (see "101 Projects" for more info; it's not hard to do). Adjust the linkage, drive it and if it still won't go into first then drop your trans.

I think that you will find your shifting greatly improved if you do all of this.

[agabriel]

A few quick questions...

1) How will the bushings in the shift linkage change the shift? Does it sound like the ones in their are worn out?

2) Does Porsche factory short throw kit include the bushings?

3) How good is the factory short throw kit? (can I get a testimonial)

Thanks,
Anthony

[Rot 911]

Originally posted by agabriel
A few quick questions...
1) How will the bushings in the shift linkage change the shift? Does it sound like the ones in their are worn out?
2) Does Porsche factory short throw kit include the bushings?
3) How good is the factory short throw kit? (can I get a testimonial)
Thanks,
Anthony

The '86 Carrera already has the factory short shift kit. The bushings will take up all the slop in the shifter which makes for more precise shifting. I have an '86 Carrera and I can only get into first while moving below 5mph. The advice you received above is spot on.