[earossi]

My 6 speed has developed some issue, with no warning. Suddenly, while out for a drive, I found it very difficult to get the car into 2nd gear. Once in gear, the car accelerated just fine. On the upshift from 2nd to 3rd, I experienced the same high effort required. However, all other shifts are normal. Neutral to 1st. 3 to 4 to 5 to 6, and down are just fine.



There are no abnormal noises from the tranny nor are there any notice of vibrations in the car other than the fact that 2nd gear (in and out) is like moving through molassess! I would greatly appreciate any ideas that would help me diagnose this item. Since the car is approaching 15 years old, could it be something in the shift mechanism......either at the shifter, or back at the shift block on the tranny that could be broken?



Thanks in advance.

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[flash]

since 2nd gear requires a fair amount of mechanical advantage, i would check to see that the shifter is in the correct position and the bushings are good, as well as checking the rear linkage for play - the problem could be there, though i tend to think it is internal



i would drain the diff and look at the fluid, looking for shavings and such

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[earossi]

[quote name='flash' post='38748' date='Jul 24 2007, 11:16 AM']since 2nd gear requires a fair amount of mechanical advantage, i would check to see that the shifter is in the correct position and the bushings are good, as well as checking the rear linkage for play - the problem could be there, though i tend to think it is internal



i would drain the diff and look at the fluid, looking for shavings and such[/quote]





Thanks Flash. Good suggestion on changing out the trans oil. It is way over due, so this will provide some reason to do it. You mentioned that you thought the issue may be internal. What internal failure would produce those symptoms? Since there is no outward sign (pending an inspection of the oil) of the failure, would you not expect issues with other gears as well?



When you mentioned linkage bushings, I assume that you are talking about the shift block that is mounted on the transmission, right? How hard is it to access that item? I don't recall if you can see it from under the car? Or, do you gain access through some cover plate?



If it is shifter bushings, what could be wrong there? I remember having a shift bushing grenade on one of my 911's, and all that produced was a "loss" of the shift pattern, making gear selection very vague?



I'll report back what the fluid inspection shows.

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[flash]

the shaft or its bearings could be going - synchros could be going - you could have wear on the gear itself - all of these should put small filings into the oil that should be able to be seen when you drain it



the linkage is at the back yes - kind of a pain to get to



the bushings i am referring to are on the shifter - there is a ball socket at the base, and 2 small ones on the sides - the ball socket has been known to crack and stay in there, making for a bit of play that can change the geometry of the shift pattern enough to make 2nd more difficult - also check the 85 degree angle in nuetral, as mentioned in the workshop manual - this is easily adjusted if the bushings are intact



again, i think it's internal, but certainly worth checking the easy stuff first

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[bob blackwell]

Hopefully it is in the linkage, but in my experience with these cars second gear is the first to go out. When I had a 1987 924S the transmission had to be rebuilt because of second gear problems. When I had the pinion bearing whine in my 968 I had the transmission overhauled at the same time and second gear synchro was the only thing to evidence wear and need replacement. Good luck, Bob Blackwell.

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[PorscheDude]

Could be the shift fork inside the transmission.

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[earossi]

Thanks for all the responses. If the shift fork failed in the trans, would I be able to shift at all? Also, since the car seems to shift into and out of 2nd fine except for a large amount of required force to make the shift, what could be hanging up in the trans?



If the synchros were bad wouldn't I see a tendancy to grind gears during the shift change?



Also, what's the best guess on area to disasseble first in the trans linkage.

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[flash]

i wouldn't disassemble it, but rather feel and look around in there as somebody is shifting, to see if anything is loose or hanging up - it's really unlikely that it's there, but worth checking into

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[rustech]

IIRC, someone mentioned the possibility of losing second as a result of the clutch fluid overheating, what is it about overheating that could cause this, and could simply having air in the line cause the same issues?

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[earossi]

I called Bobby Hart at California Motorsports this morning to discuss my transmission issues. He, like Flash, believes that more than likely I have an internal problem with the transmission. One thing that he suggested was to dump the oil and determine (by measuring what comes out) whether the transmission was low on fluid. I had not suspected this since there are no visible leaks, but I will check this out first.



When I asked him what type of oil to put back into the trans, he suggested any of the oils that meet GL5 with a weight of 75-90 or 75-80. He specifically warned to not use Swepco oils since he believes they don't work well with the synchro design of the 968 trans. I didn't have the time to question the basis for his suggestion.



Regarding costs to rebuild the tranny, he referenced some invoices he had on hand that called for a complete rebuild with all new bearings and syncros, but no new major parts. He also added in the cost of a new 1-2 slider assembly which was his guess as to what has failed in my trans. So, basis the above, his guesstimate was about $2900 plus shipping. Since the trans weights about 180 pounds, he believed that I could see freight costs of about $125 to $150 each way, if I deliver the trans boxed to a freight terminal.



Which brings me to the last thing which is pulling the trans from the car. The task looks straight forward escept for the two tasks of sliding the splined power shaft forward and also disconnecting the shift mechanism at the transmission, which looks like a job for very small hands that can be contorted!! Are there any hints out there on how to accomplish those two tasks?

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[PorscheDude]

"Which brings me to the last thing which is pulling the trans from the car. The task looks straight forward escept for the two tasks of sliding the splined power shaft forward and also disconnecting the shift mechanism at the transmission, which looks like a job for very small hands that can be contorted!! Are there any hints out there on how to accomplish those two tasks?"















This is the easiest part. Once the coupler blot is removed, the coupler just slides forward. Where the shift linkage meets the shift rod just cut the saftey wire and remove the bolt. When you are laying under the car there is alot more room than you might think.

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[Ryan]

I have not pulled the 6 speed in the 68, but I have done the 5 speed in my 944S. There is a big plug on the trans that removes to expose the splined shaft. There is a collar that slides up and down the shaft. There is a shaft in the torque tube and one in the tranny and the collar is long enough to go over each. You just loosen the collar lock and slide the collar toward the torque tube. Seems like I made a reference mark with paint for reinstall.



I don't remember the shifter being a problem. You had to cut a wire that went through the head of the bolt that holds the shaft to the linkage. In 944s the linkage had to be removed from the shifter as well , but I don't think it does for the 968. Not a lot of room to work on top of the tranny. though

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[JWahlsten]

My car didn't have any safety wire attached to the shift linkage. If you have a long extension for your 3/8" drive it is really quite easy to remove once the driver's side rear wheel is removed.



Once the bolt is all the way out, and you do need to pull it out. Just make like you're shifting to second and the linkage will come free.

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[earossi]

All,



Thanks for your responses. So, it sounds like disconnecting the driveshaft collar and shift rod are really not that hard. So, as I see it, after moving those items out of place, I just drop the half shafts, disconnect a ground strip and wiring that goes to the backup light switch. support the box with a jack and then pull the four bellhousing bolts and the two cross support bolts and she should just drop right on down. Is that correct?



So, assuming that the first two items go well, am I looking at about another half to full hour to have everything broken loose? I have pulled the powertrains out of 911's several times, and finally got it down to a science that allowed me to have the train out of the car in about an hour. Sounds like the 968 is almost easier to pull. Having said that, I have probably cursed myself!



My first job is to dump the existing fluid and check for metal shavings. I'll then refill the system with clean new oil and see if my issues improve. If that fails to solve my second gear problem, I'll take a close look at the shift block mounted on the trans and the shifter bushings. Lastly, if all these items appear ok, I'll have to conclude that I have internal damage to the box, and I'll go ahead and pull the trans.



Out of curiosity, has anyone on this forum ever disassembled their 968 trans? I've watched race teams disassemble 911 boxes at the track, and they appear to be designed for rapid disassembly. The last box that I disassembled was a British trans out of an MGB (a long time ago), and the process was pretty straight forward. I'm just wondering what skill levels would be required to disassemble a 968 trans?

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[earossi]

OK I spent some time on Saturday looking over the trans in my car. I drained all the trans oil. Found it to be very dark with some odor. Could not see any metal shavings at all. When I measured the amount of old fluid I drained out, it was about 2.25 quarts, which is about a half quart less than the manual indicated. When I refilled the trans with fresh fluid, it took right at about 2.75 quarts.



So, the first question is: Assuming that the past owner had filled the trans to max, where did a half quart of fluid go? There are absolutely no indications of present or past leakage at any of the seals.



Second question: Are these boxes sensitive to running a little low on fluid? And, if so, would that explain my sudden increase in force required to shift into and out of 2nd gear?



Once I had her all buttoned up, I drove her to get the trans hot. Box shifts fine both up and down through the gears, including reverse. But, there still is more force required in dealing with 2nd gear. And, there are no identifiable noises from the box.



Lastly, I have one really awkward question. Since I had the car up on a lift, I was able to walk under the car and had very good visibility of the trans and everything on both sides of the trans. Having said that, I was not able to locate a transverse mount for the trans. If I am correct and there is no transverse mount, then the entire box is hanging cantilever off the central tube bell housing. What am I missing here? Since I was not able to see on top of the box, is the mounting on top?



One more piece of info. I called a shop here in the Chicago area who advertises in the local PCA mag and who also hosts some events at their garage. When I asked them for the cost of labor to rebuild the box, they were very matter of fact. They want 5 hours to pull/install the trans. And, they figure 34 hours to rebuild the box. At $100 per hour, that puts the labor cost alone at $3900. Figure adding in about a grand for parts, and you have a $5000 rebuild. What has been the experience on this board with all-in costs to do a trans?



Lastly, I was able to download both the 944 and 968 manuals from the German website suggested by someone on this forum. I'm really gratefull!



So, should I pull the box or try some other type of oil in it to see if I can get 2nd gear improved?

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[flash]

there is a mount way up on top (lol - or there should be) - it's a hanger type - one long bolt goes through it



that price is high - they probably figure they need to charge you not only for the work they are doing to your car, but also the time your car is on the rack preventing them from doing other work



i would yank it and send it to bobby if you decide it needs to be done - he is the guy who does the porsche racing team boxes, and is the best in the country

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[earossi]

[quote name='flash' post='39161' date='Jul 30 2007, 09:38 PM']there is a mount way up on top (lol - or there should be) - it's a hanger type - one long bolt goes through it



that price is high - they probably figure they need to charge you not only for the work they are doing to your car, but also the time your car is on the rack preventing them from doing other work



i would yank it and send it to bobby if you decide it needs to be done - he is the guy who does the porsche racing team boxes, and is the best in the country[/quote]





Thanks Flash. I agree on using Bobby Hart. When I talked with him, he was extremely knowledgable and quoted pricing that sounded more reasonable.



ON the trans mount, it always blows my mind when the writeup in the manual is inaccurate, and they don't give you any pictures to compare. I'll see if I can snake my hand up on top of the box to see if there is an attachment lug there.



Thanks.



Ernie

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[flash]

let me know if you have trouble - i think i have an extra mount here somehwere and could dig it out and snap a pic

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[earossi]

Well, it's been over a week since I last posted on my trans issue (hard shifting into and out of 2nd gear). What I ended up doing was flushing out the old trans fluid, which was fairly putrid now that I think back on it. Since I do appear to have slight seepage leaks out of both axle seals (at the trans), that may explain the fact that I was a little less than one quart low on trans fluid. I replaced the fluid with Mobil 1 synthetic 75W-90. The Mobil 1 made a step change improvement in shifting (though the shift was still a little bit harder than the other gears). Now, after driving the car a little (about 150 miles), we appear to be back to normal, or very close to it.



So, since I am a believer that machinery does not fix itself, I am at a complete loss for the improvements attributable to just changing trans fluid.



I thought that I would just pass this along; and, perhaps someone has a reasonable explanation. However, at this time, it appears that I have dodged the bullet (for now), and won't have to shell out for a rebuild..

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[bob blackwell]

When I bought my 968 it had 64,000 miles on it and the transmission shifted a bit sluggishly. When the car was cold it was harder to shift than when it warmed up (bought in January). I drained the transmission and refilled with new SWEPCO transmission oil and it immediately worked much better. At about 100,000 miles I had the pinion bearing whine and had the transmission rebuild and the pinion bearing replaced and properly tensioned. New second gear synchro, bearings and seals for $2,500 including R&R. Refilled with new SWEPCO again and it had been working fine with 175,000 miles on it at present. I disagree with Bobby Hart on the SWEPCO oil, it works fine in my car. Good luck, Bob Blackwell.

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