944 Shifting is 'Crunchy'

[adamjhilton]

I purchased an '87 944 S a couple of months ago. From the PPI, I knew that the shift level was worn and needed replacement. After a few weeks of driving, I noticed that it was starting to feel 'crunchy' when I would shift -- particularly going into 3rd gear. I replaced the level myself with the part here from Pelican hoping that this would fix the issue. It didn't. So, I opened it back up and adjusted the positioning of the level forwards and backwards until it got a little better, but it's still not shifting as smoothly as I would expect.

Full disclosure: this is the first car I've ever owned with a manual transmission, so I really have nothing to compare the feel of shifting it to. I just hope I didn't do too much damage to the transmission learning to drive a manual. I have been riding motorcycles for decades, so I at least understand the fundamentals...

At any rate, to define 'crunchy': I don't have any issues finding the gears; except reverse sometimes. The transmission doesn't make any grinding noises or anything like that. The shifter feels tight -- certainly tighter now with a new lever. When the car is idling, I can shift through the gears just fine. However, when I accelerate, something grinds or crunches as I move the level into the next gear. Sometimes 3rd even feels like it kicks back at me as I shift.

Thoughts?

Thanks!

[Spring44]

Maybe bad syncros in the transmission or maybe the clutch is not disengaging completely during shifts due to a failing hydraulic clutch master or slave cylinder.

You should hope that it is clutch hydraulics failing, because that is easier to fix than replacing syncros. I think that this is more probable as the cause than bad syncros, unless the PO really abused the transmission. Good luck!

To test, start your car and at idle push in the clutch pedal and engage each forward gear, then engage reverse. If the forward gears can be engaged with little or no grinding, but reverse grinds, that is an indicator that the clutch is not completely disengaging. Since all of the forward gears are synchronized they will tend to go ahead and engage with little resistance. But reverse is not synchronized and it will tend to grind because the clutch is not completely disengaged.

[SolReaver]

Clunking in gear may be a sign of a bad synchro. I have been living with a clunky 2nd for ages. If your linkage is solid and your clutch is properly adjusted,, it might just be a bad synchro. You could replace the transmission gear oil, that helped a bit for me. I also tend to double clutch and shift into the affected gear a little slower while matching rpms, like I was shifting a truck.

IF it is a bad synchro, the "fix" involves removing and likely replacing the transmission. Removing the transmission is a BIG job and so I have decided to live with my bad synchro.

[RedCarGuy]

When you say shift lever I assume you're talking about the part in the cabin. Before you get too deep into synchros, try the low-hanging fruit. Check the shifter linkage on the transaxle too. There are two parts that you should inspect for any looseness and look at the condition of the rubber bushings. There is the shifter itself and a pivot arm on the back. If the rubber here is worn out it might cause what you're describing.

I would recommend changing these parts and using the pieces from only944.com they are high quality and make shifting much more precise than before by eliminating all the rubber back there. Also try a fluid flush, it is cheap and easy to try before doing anything more drastic.

[adamjhilton]

Originally Posted by Spring44

To test, start your car and at idle push in the clutch pedal and engage each forward gear, then engage reverse. If the forward gears can be engaged with little or no grinding, but reverse grinds, that is an indicator that the clutch is not completely disengaging. Since all of the forward gears are synchronized they will tend to go ahead and engage with little resistance. But reverse is not synchronized and it will tend to grind because the clutch is not completely disengaged.

Thanks, Spring44! I did this test on the way into work this morning. I was able to shift from forward gears to reverse with about the same feel. So, I don't think this is it. I did just flush the master cylinder a month ago.

Incidentally, I can't shift from 5th to reverse directly. I assume this is a safety feature.

Getting back to the shifter level (the one in the cabin): I replaced this a couple of weeks ago and the shifter is tighter than it was; but with the shifter in 1st gear, I can still move it side to side about an inch, inch-and-a-half. Having no frame of reference, is that normal? If not, I may need to Google how to inspect/replace linkage components as RedCarGuy suggests.

I could replace the transmission fluid as SolReaver suggested as well. I'll have to review the maintenance records that came with the car to see when it was last done.

I'm holding out hope that this won't be a new transmission...

[RedCarGuy]

Here is a write-up with video on replacing the shifter to give you an idea.

https://www.only944.com/instructions/shortshifterinstall/

[adamjhilton]

I watched this video. I also found this one here: https://www.youtube.com/watch?v=3qQynDMVhUY

This guy takes it one step farther and replaces the welded stud on the shifter arm: https://www.youtube.com/watch?v=fWnC9gD1tic

So, I think my next step is to install this short shifter kit and see if that resolves the crunchiness:
https://www.only944.com/partscatalog/only/shortshifter/
https://www.only944.com/partscatalog/only/shiftlinkagearm/

I'll have to pop the tire off tonight and take a look at home much play I have down there.

[adamjhilton]

Okay, I popped the wheel off and had my wife work the shifter while I observed. There was a little bit of play in the shift linkage, but the shift linkage arm was basically just flopping around. Obviously, those rubber bushings are shot!

I imagine this could this be the cause of the crunchy shifting...

I should probably replace the shift linkage with the above short shifter while I'm in there.


Edit...

Damn! I wish I knew about only944.com before I bought a shift level from Penguin! I think this one is much better: https://www.only944.com/partscatalog/only/shifter/

[adamjhilton]

So, I've been trying various things with shifting to see what helps with the crunchiness. What I've found is that when I shift up, I let the tachometer come back down to ~2500 RPMs before I put it into the next gear. This alleviates most of the crunchiness.

Thoughts?

[kdjones2000]

Sounds like synchros....

[Cad.Guy]

What is the difference in synchros ?
Some list the same part for 1 - 4 some only 2-4
The PET lists 2 numbers for all 4.
Which is the best way to go ?
Is the higher number an update?

[944 Ecology]

The PET is more likely right than the aftermarket sellers.

[CarGuyNeil]

Call a dealer and ask the Parts Department. They will know.

Sent from my SM-S928U using Tapatalk

[Cad.Guy]

thanks

[Cad.Guy]

Does anyone make HD synchros ?
I have read about some that are carbon embedded ?
I'm not racing or slam shifting just want the best available.

[Monkey Wrench]

if you drain the tranny oil look for brass in the oil.

getting your revs right and double clutching properly is important. I never try to shift quickly, focus on smooth shifting. Ive bought cars that ad this problem and fixed them by shifting at the right speed, it wears the synchros back in..

if you get some driver that doesnt; know how to shift properly they will basically cause the synchros to wear or get roughened, sure you can take it all apart, thats expensive or a lot of work..

First I'd try to just really focus upon shifting at the right RPM and if the shifter doesn't want to move very gently , never force it in, instead, go back to the gear that best matches your car's speed. normally people just doubleclutch when downshifting but if you find yourself rolling along and its not in gear try doubleclutching anyway.

any time you are pulling the shifter and hearing it not cooperate, grind or clunk, you are basically wrecking the syncrro's ,
try to shift with just two fingers, not your whole hand. you'll be less tempted to get frustrated and bang it in, doing so will cause damage. doing that will help you feel better and remove the temptation to get aggressive.

if you want to run the snot out of your car, go ahead floor it ! but Id wait till second gar and don't try to make time with fast shifts.. If you aren't racing, you never need to shift fast. That's what causes it.

[wwdwgs]

MW,
People, who drive Volvos, shift slowly, those who drive Porsches - quickly. You can benefit both approaches.

[Monkey Wrench]

sure you can any manual transmission shift fast and rough and it can easily be fixed with big fat cheque.

The OP is learning because he hasn't driven standard , prior. I think its good advice to move the shifter a bit slowly and not bang it into gear or pull it out of gear without the clutch fully depressed.

he does seem to know how to doubleclutch and that requires some feel and practice. its the same action on a bike. some with lots of experience really have it down to a fine art.

Id encourage practicing that because having the revs right and shifting properly does have a bit of a learning curve, there is definitely some technique to getting it right and every car you sit in will react a little differently.

My suggestion is focus on smooth shifting before you try to become a quarter mile racer.

I think how you drive is more dependent on your driving style and habits than what car you sit in, but see no point in disputing about that, it just becomes a difference of opinion and not very helpful to anyone, drive how you like..

"I let the tachometer come back down to ~2500 RPMs before I put it into the next gear. This alleviates most of the crunchiness.
"
Yes to that, Id say definitely, dont be in a rush, instead get a feel for smooth shifting, shifting at the right RPM to match the driving style, If hard driving, sure take the revs higher to get more power.. But with a car you can't pass in front of you in traffic, take your time, banging your transmission around isn't helping you get anywhere then.

yes letting the revs drop by just the right amount is important. you can shift without the clutch if you have it just right but wouldn't recommend it right now.. but just making the point..

when you shift , and if you doubleclutch properly, what you are doing inside the transmission is making the gears spin at the same relative speed, then the synchros are a lot less stressed than depending upon them to match the gear speeds, by friction. It simply wont come by way of type, it takes some practice to get a feel for it. If you miss a shift, Id say, dont force the situation , instead put the clutch back in..

basically match the speed of the car with the gear and the RPM's , that will reduce stress on the synchros. if you are coasting, because you blew a shift, dont worry, dont force it..

with it out of gear and the clutch in , you have disconnected the engine from the drive gears and the driven gears.. if you get stuck and its not in gear,, you might want to lift up on the clutch to drive the "drive gears" to enable you to once again attempt to get the speed to match properly, get it into a gear, even one down from the intended gear,, then try again. If you instead apply force to the shift lever you are forcing things, that's how you wreck a transmission.

The synchro's might be worn by poor shifting , so I'd drain the tranny oil and check it out, see if there is a lot of brass... is the tranny low on fluid?

there might be something off with the shifter fork. could be problems with external play in the shifter linkage etc. Id check that first, before the rebuild. I remember snapping a shifter fork as a kid by pulling it out of gear without the clutch fully depressed.. then I got to take a VW tranny apart and learn.

shifter fork might have a loose pin or grub screw or similar, it can wear too,, hard to see without disassembly.

most cars have springs in the clutch disks, I know the older ones like my early 85 have an inherent problem with the rubber center, due to rubber age-rot.. maybe others with experience on this newer clutch arrangement can elaborate about the inherent issues surrounding this particular clutch release mechanism. I think there is some rubber near the throwout bearing. perhaps a similar issue with rubber deterioration due to time.

i seem to recall some parts around the throw-out bearing can have similar issues but lets ask the experts.. Ive been hoping to find an aftermarket clutch with springs for mine. im finding better availability on the aftermarket parts for the S2's than for the early versions.

"I did just flush the master cylinder a month ago. "

ok so you changed the fluid? did you bleed it properly to let any trapped air out, air in the system will cause the clutch not to disengage fully. your foot may hit the floor before it is completely disenguaged.. you should be able to tell by the distance from the floor where the clutch starts to grab, if the pedal seems too close to the floor Id try bleeding it again to make sure. extra floor mats can save the carpet, but some might interfere with pedal movement.

It can be a little troublesome to get the air out of the line, if it helps you can break the flex line open a little to try to get the air out, Once the clutch is functioning somewhat, which it seems to be, then you should be able to bleed it properly.

if it is full of air then you can have an issue where the piston in the slave cylinder isn't moving because you are basically just compressing air .. in that case you can crack the line and et a helper to work the clutch pedal, to get the air out. that might be a problem if the system looses all its fluid , this clutch is at least functioning somewhat so thats only applicable if you drain all the fluid or replace the slave etc.

yes slop in the external shifter linkage can cause the shifter fork to not move to its proper extent so checking and fixing that is a good first step and may solve the problem.

if you have trouble going into reverse and find that the gears grind when you are at a standstill it may be likely that the clutch isn't fully disengaged... so then what is happening is that the gears are still turning inside the transmission because the drive gears are turning because of some clutch engagement while the driven gears are at a standstill

you can have sort of a similar issue if you are rolling along at some speed in neutral with the clutch in, then the drive gears stop without anything to drive them while the driven gears are of course running as they are connected to the back wheels. lifting the clutch will then cause the drive gears to spin again.

I don't race but racing is a lot about smooth driving so a racer has in depth knowledge of all this and is matching speeds, not abusing the transmission by hard shifting without paying attention to gear speeds.. its not just a matter of slamming the shifter into whatever gear you desire... similar with truckers who shift without the clutch..

you can shift without the clutch, when you can do that smoothly you are matching the drive and driven gear speeds accurately. you can practice that but I'd pick a less expensive car.. I got quite good at it when I drove the bosses car as a kid.. Id just use the clutch to start and then try to never use it when driving, that helped me get it down better. His Ford Fiesta did live on lol..

when you step on the cluch you have disenguaged the drive gears and they arent being driven by the engine nor the wheels so they are then slowing down, this pause between shifts allows those drive gears to slow and when you shift into the next higher gear, and get that right the synchros arent; mating the gear speeds , they are already going the right speed, that's easier on the synchromesh rings. the synchros help mate the speeds by way of friction before engagement so if the speeds area little off they help correct that..

when you doublecluutch to gear down, its the opposite then you are taking it out of gear, lifting the clutch , giving throttle thus speeding up the drive gears so that when you shift to the next lower gear the speeds match up. then the gears slip in easily because they are going the same speed relative to one another. getting that just exactly right does take practice.

if the gear speeds , engine speed , car speed dotn match right and you let the clutch out then there is a shock through the drivetrain..

sure you can "race" by doubleclutching , gearing down , slowing the car by way of speeding up the engine like a gyro, half your foot on the brake, making a corner, shifting up with the revs really high and then obtain a little boost upon letting the clutch out, in that you are basically storing power in the fast spinning engine rather than wasting it braking.. this is using the kinetic energy to your advantage.. I find it fun to do in my 66 volvo.. I did lots to it , balancing, large pistons hot cam polished ports etc etc,, to make it have more power but kept the clutch at the standard weight.. I lowered the rear axle ration, it works well in that car.

the transmission I have in that car is a bit rare with the overdrive, it has a longer mainshaft than a standard 4 speed.. no LSD but otherwise its basically like a hopped up 123GT.. It wont corner like the porsche but it's still an absolute riot to drive

I also have a 740 and a 240, they are workhorses and automatics, great cars.. not hot rods..

[wwdwgs]

MW, as always, great write-up.
OP,
This could help:
When you upshift from 1 to 2 at (let's say) 4000 RPM's, do this: reach RPM's, press clutch and saying "clutch", shift to N, saying "neutral", and shifting to second, saying "second", clutch out, saying "clutch".
"clutch, neutral, second, clutch". By the time you are ready to shift from N to 2, the engine revs drop by about 500 or 600 from 4000 to about 3500 or 3400.
This difference matches speeds of the engine and the gear box.
Roughly, the RPM difference between the speeds is about 1000 at red line: 4000 RPM's at 1-st, will match 3500 RPM's at 2-nd, 4999 RPM's at 2-nd will match 4449 1/2 RPM's at 3-rd etc. Therefore, at 3000-4000, the difference would be about half - 500.
Like others said above, sifting with proper RPM's will allow you to use 2-3 fingers to move shift lever to N and desired gear with almost no effort. don't grab the shifter, but, rather, hold it and move or guide it into a desired location.
Read a book by Vic Elford Porsche High Performance Driving Handbook ISBN 0-87938-849-8 (1994), where he explains how to drive SMOOTHLY. Smoothly is a key.
I learned to drive stick on my first Porsche 914 2.0. I and my friend drove his car to pick up 914, then we drove back to drop off his car and, then, I drove to my home, then, I drove his back home and drove back to my home. That was a great experience and hard learning. Off course, I burned the clutch a few times at the starts from first. I hated stop signs, traffic lights and parallel parking and, also, slow traffic speeds.
Later, I drove my 914 on empty streets when it was snowing and learned how to skid. I almost crashed...
With time I learned how to shift smoother and started to enjoy all those stop signs, traffic lights, etc.

When you'll learned how to properly match RPM's, then you could think about driving without depressing the clutch (except the first gear). This skill will come handy if your clutch won't work at all. Start moving with starter in 1, then, sift with proper RPM's. I drove two different stick-shifted cars through busy (and sometimes hilly) cities. It was a nightmare starting standing uphill.
Enjoy your Porsche smoothly.

[Monkey Wrench]

when there is some mismatch in gear speeds, the synchro rings help the mating gears to start turning the same speed as each other so that as the gears move into mesh they slide in, otherwise it would be harder to change gears without them, some old cars were built without synchromesh..

the point I am trying to make here is that there are two ways for the gears to be mismatched, gear A is going faster than gear B or, gear B is going faster than gear A.

so lets say the problem is that they shnchro rings are worn so the transmission becomes a little harder to shift.. you may find that changing the style slightly helps..

I believe that the syncros wear in two ways and it is likely common that one side wears out first..

when you doubleclutch and gear down you may note that when you let the clutch off you can control it a little , in one instance you may make it so that when you release the clutch the car lurches akead slightly, the other way you may find the car slows when you let the clutch up. even though both instances are downshifting into the same gear..

if the gears are perfectly matched in speeds, you would notice no surge ahead and no braking action as they are matched.

by getting used to the feel of it, you can control the two different situations..

since one side of the synchro is worn and the other is not then you may find that adjusting this technique favors the side of the synchro that is less worn , resulting in a smoother shift, despite the fact the syncromesh ring has some wear..

by not stressing the synchro and driving it for more miles what can happen is you then wear the synchro back in and thus improve shifting , you are basically reshaping the point on the synchro and smoothing it out.. that's a way to fix it without taking things all apart.

what it requires is some attention to the habit and learning how to shift smoothly every time,, as soon as you are grinding gears or feeling them clunk you are damaging the synchro ring..

each gear has a ring first and second may be the most susceptible.

Ive had old cars that were hard to get into first from a standstill , so Id sort of slip it in when the car is still rolling before I came to a full stop.

often in my old volvo I will doubleclutch down as I approach a light , in that case Im doubleclutching and using the engine as a brake , Ill still apply brakes but I'm taking some stress off the brakes..

often when you hear very experienced riders on Harley Davidson's, you can hear them doing this very well.. usually when approaching a light..

sure they use their brakes but thy also use the transmission and compression to slow themselves and to do that they doubleclutch.. These guys are basically in tune with their machines.. they dont want to wreck them, they really care about them..

also as they are coming to a stop, if they are in first already , then before stopping , but rolling at near waling speed, the light goes green,, then they can simply dump the clutch and take off in first
Since they are already put the bike in the correct gear for their speed.. they have prepared for the event.. they dont need to put their foot down on the pavement or stop the bike completely..

I think its an example of the fact that you dont need to know how a car works to drive one, but if you do it helps you unserstand the physics. after a million instances of almost the same action with only slight variations in habits,, you become more in tune with it all.. like riding a bicycle its a learned habit that once you get it down, you dont really loose it..

if the OP can doubleclutch on a bike then he already has learned it, he just has to get the to get the habits fine tuned then they will be easier to control and make them work to his advantage.

a car has two distinct actions, the wheels are slowing the car, it is decellerating , or the wheels are driving the car, he is accellerating..

every part in the driveline, transmission shaft splines U joints or CV joints , the gears in the tranny the load on all those bearings, the rear axle gears driveshaft splines , the axle shafts may be keyed to brake drums,, etc.. every point along the drive train is constantly changing between the two states..

if you lift a wheel up and the car doesn't have LSD then you can simply turn the back wheel either way with the engine in first and not running..

now you can note quite considerable play,, every little place where there is freeplay all through the driveline is added together so its a good way to tell easily how worn the drivetrain is..

if you have someone turn the wheel back and forth like that, for you. you can go put your hand on things like CV or U joints and feel the movement, to isolate and detect worn parts.

with older worn out cars, they can develop a lot of slop , the result is driving along at 10 MPH and feeling the car surge ahead and back in a jerky motion because they are in a state of limbo and that freeplay keeps reversing.. once driving, acellerating or decellerating constantly , it goes away.. this can make it uncomofrtable to drive a worn car in heavy traffic.
the harder you beat on it, the faster it wears and it involves a whole lot of parts.

I think if you are shopping for a particular car you could do that and take note, the car with less freeplay is the one you want, because fixing that is very expensive , it is involving stacked freplay through the entire drivetrain.

a driver who abuses his machine can wear it out in less miles. If the driver drove like grandma, then that's the one you want..
the kid that went hot rodding in his mom's car.. visually , by looking at the car, hard to tell.. you can drive slowly , put it in that limbo state, take note of how it feels,, a tight car is nicer to drive.

if Im shopping Id avoid a car with a boom box stereo, its a sign.. someone younger owned it and we all tend to wreck out first cars more as we are then young and a bit more rough on things..

Ive noticed that when handing antiques I can note the nature of people, say I handed someone an antique violin, said no more , just observed..

well some will carry it and place it back down carefully in a safe place, they will treat the thing like a baby.. others will put it down more roughly,, its just a difference in human nature. same with drivers.