Downshift Shudder - I have HAD IT - LONG POST
06-09-2003, 11:49 AM
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Downshift Shudder - I have HAD IT - LONG POST
OK, I give up. $5K and still no fix on my vibrating 2nd gear downshift on my 30K mile 944 S2 cabriolet that is literally perfect in every other way. So far:
1) Replaced clutch with spring center. Clutch was overheating in traffic, and started to have a shudder on downshifting to 2nd. Took it to a reputable shop for a clutch job, pretty simple, right? But when done, it did not overheat in traffic, but it still had severe vibration/shudder on downshift to 2nd if revs not exactly matched, does this in no other gears. Shop threw up its hands and said not their fault, they did a good clutch job based on the wrench's "vast experience." This is a nationally known shop in Northern VA who basically invented the aftermarket chip business...Owner agreed to tear it down under their 12 mo/12K warranty, but if nothing "looked bad" I'd have to pay labor ($1400) again. So that is the last nickel I will spend with them. Too bad. Rennlisters said that some had developed this shudder with the spring center, if the flywheel was not turned, so.....
2) Took it to a dealer, also in NORVA. I asked them to "diagnose the problem" with 2nd, had their chief wrench drive it an showed the shudder/shake to him. He says, clutch, maybe a bad flywheel. Turns out the prior shop DID NOT RESURFACE, again based on "experience." The dealer REDID the job, resurfaced the flywheel, and put a rubber stock clutch back in, measured everything in the drivetrain, specced the torque tube bearings, adjusted the clutch pedal, bled the hydraulics, etc. Guess what....did it again, this time on the way out of the dealer's lot! Their answer - let it break in. If it did it before the first clutch, after the first clutch, and now after the second clutch, what does breaking in have to do with a shudder in 2nd only downshift?????
2)OK, Rennlist posters and email suggested:
- Tranny mount (I did this one, phwew what a pain, no dice). Have not tried gacking it up with stuff yet to stiffen it up a bit but I doubt that is the problem.
- Motor mounts (I did this one also, worse than tranny mount!)
- Tranny is bad, synchros or some issue with 2nd gear, or maybe a pinion, etc.(See below...)
3) Last resort - a replacement tranny. If this only does the shudder in 2nd downshift, has to be tranny... or so said 3 different Pcar tranny shops nationwide...I found a decent 77K mile S2 tranny sort of locally (in PA from a well known dismantler, AutoTech Plus) Drove up to get it (5 hrs round trip but a nice ride), slapped it in yesterday... and viola - IT STILL VIBRATED LIKE A MOOSE ON CRACK. I was so frustrated, my kid and I put the original tranny back in last night. I'm getting pretty good at weaseling stuff in and out of this beast by this time.
Lets have a vote: What next:
a) Tranny mount gackup
b) Let it break in for 1000 miles and hassle the dealer on a bad diagnosis. Good luck on that front.
c) Find out who the BEST 944 drivetrain guru is in the free world...and get another opinion. I tried expert George B already, by the way, his suggestion was a bad 2nd gear. Any ideas on gurus?
d) Any other ideas (CVs, shocks, torque tube, bearings, whatever???????????????)
For Sale:
1) Good used tranny, 77K miles, from 90 S2. Will ship. $1000
2) Good used Sachs S2 spring center clutch kit, $1400 list, $700 OBO. Only 235 miles, not even broken in.
1) Replaced clutch with spring center. Clutch was overheating in traffic, and started to have a shudder on downshifting to 2nd. Took it to a reputable shop for a clutch job, pretty simple, right? But when done, it did not overheat in traffic, but it still had severe vibration/shudder on downshift to 2nd if revs not exactly matched, does this in no other gears. Shop threw up its hands and said not their fault, they did a good clutch job based on the wrench's "vast experience." This is a nationally known shop in Northern VA who basically invented the aftermarket chip business...Owner agreed to tear it down under their 12 mo/12K warranty, but if nothing "looked bad" I'd have to pay labor ($1400) again. So that is the last nickel I will spend with them. Too bad. Rennlisters said that some had developed this shudder with the spring center, if the flywheel was not turned, so.....
2) Took it to a dealer, also in NORVA. I asked them to "diagnose the problem" with 2nd, had their chief wrench drive it an showed the shudder/shake to him. He says, clutch, maybe a bad flywheel. Turns out the prior shop DID NOT RESURFACE, again based on "experience." The dealer REDID the job, resurfaced the flywheel, and put a rubber stock clutch back in, measured everything in the drivetrain, specced the torque tube bearings, adjusted the clutch pedal, bled the hydraulics, etc. Guess what....did it again, this time on the way out of the dealer's lot! Their answer - let it break in. If it did it before the first clutch, after the first clutch, and now after the second clutch, what does breaking in have to do with a shudder in 2nd only downshift?????
2)OK, Rennlist posters and email suggested:
- Tranny mount (I did this one, phwew what a pain, no dice). Have not tried gacking it up with stuff yet to stiffen it up a bit but I doubt that is the problem.
- Motor mounts (I did this one also, worse than tranny mount!)
- Tranny is bad, synchros or some issue with 2nd gear, or maybe a pinion, etc.(See below...)
3) Last resort - a replacement tranny. If this only does the shudder in 2nd downshift, has to be tranny... or so said 3 different Pcar tranny shops nationwide...I found a decent 77K mile S2 tranny sort of locally (in PA from a well known dismantler, AutoTech Plus) Drove up to get it (5 hrs round trip but a nice ride), slapped it in yesterday... and viola - IT STILL VIBRATED LIKE A MOOSE ON CRACK. I was so frustrated, my kid and I put the original tranny back in last night. I'm getting pretty good at weaseling stuff in and out of this beast by this time.
Lets have a vote: What next:
a) Tranny mount gackup
b) Let it break in for 1000 miles and hassle the dealer on a bad diagnosis. Good luck on that front.
c) Find out who the BEST 944 drivetrain guru is in the free world...and get another opinion. I tried expert George B already, by the way, his suggestion was a bad 2nd gear. Any ideas on gurus?
d) Any other ideas (CVs, shocks, torque tube, bearings, whatever???????????????)
For Sale:
1) Good used tranny, 77K miles, from 90 S2. Will ship. $1000
2) Good used Sachs S2 spring center clutch kit, $1400 list, $700 OBO. Only 235 miles, not even broken in.
06-09-2003, 12:06 PM
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by PaulK:
<strong>2) Good used Sachs S2 spring center clutch kit, $1400 list, $700 OBO. Only 235 miles, not even broken in.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Please don't hate me for pointing this out, but Pelican Parts has those kits new for $532.50. I might try to re-coupe some losses from that first shop.
<strong>2) Good used Sachs S2 spring center clutch kit, $1400 list, $700 OBO. Only 235 miles, not even broken in.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Please don't hate me for pointing this out, but Pelican Parts has those kits new for $532.50. I might try to re-coupe some losses from that first shop.
06-09-2003, 12:08 PM
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Paul -
What a mess.. sorry to hear this is happening.
Do you get the shudder in 2nd gear at all RPM ranges? Is it the same feel when you downshift to 1500rpm or 5500rpm? It is a very fast sudden vibration, or more of a slow rolling vibration? Any noise with it? If you slip the clutch hard, does it shudder?
Let us know.
What a mess.. sorry to hear this is happening.
Do you get the shudder in 2nd gear at all RPM ranges? Is it the same feel when you downshift to 1500rpm or 5500rpm? It is a very fast sudden vibration, or more of a slow rolling vibration? Any noise with it? If you slip the clutch hard, does it shudder?
Let us know.
06-09-2003, 12:49 PM
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I have a similar issue. And by similar I mean a vibration in the drive train as opposed to the engine. From what I've read and found out it's my rear shocks. They either need to be adjusted or replaced. So that's my next step. Or at least have the rear shocks tested to see if they are bad or not.
And mine started to after going to a spring centered clutch. But the work was done by a very reputable shop.
And mine started to after going to a spring centered clutch. But the work was done by a very reputable shop.
06-09-2003, 01:03 PM
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Thanks, guys. As far as the clutch kit price I guess I got tooled. Anyway I plan to sell both on ebay if possible. I just don't want to throw more big bucks at the car right now.
Q: Do you get the shudder in 2nd gear at all RPM ranges?
A: Mostly 3K to 1.5K. It shows up if you let the clutch out after a downshift, like you are in traffic, and you don't match revs like you are downshifting for a fast turn.
Q: Is it the same feel when you downshift to 1500rpm or 5500rpm?
A:1500 is much worse.
Q: It is a very fast sudden vibration, or more of a slow rolling vibration? Any noise with it?
A: The shudder starts mildly as you let the clutch out, then builds up to the point where the shifter is rattling back and forth, the tranny is hitting the undercarriage and banging around!
Q:If you slip the clutch hard, does it shudder?
A: Yes, but it seems to stop sooner and does not build up to a creshendo.
Q: Do you get the shudder in 2nd gear at all RPM ranges?
A: Mostly 3K to 1.5K. It shows up if you let the clutch out after a downshift, like you are in traffic, and you don't match revs like you are downshifting for a fast turn.
Q: Is it the same feel when you downshift to 1500rpm or 5500rpm?
A:1500 is much worse.
Q: It is a very fast sudden vibration, or more of a slow rolling vibration? Any noise with it?
A: The shudder starts mildly as you let the clutch out, then builds up to the point where the shifter is rattling back and forth, the tranny is hitting the undercarriage and banging around!
Q:If you slip the clutch hard, does it shudder?
A: Yes, but it seems to stop sooner and does not build up to a creshendo.
06-09-2003, 01:05 PM
#7
Nordschleife Master
This is a typical sudder... Anytime you go to the spring centered clutch on the s2 it will do this at least everyone I have seen (4). I have done 3 clutch jobs. Just keep driving on it and get used to syncronising your downshifts diffrently and there will be no problem. Ohh and your send gear problem is more then likely a bad syncro. Though mine was a bad bearing which blew and then blew 1-2nd gear and 4-5th gear. Because the tranny is ****ty and anytime you power from 1st-2nd and chirp the tires it basicly mashes you gearbox.(really ****ty design....) You end up with a car that is much slower after paying for the rebuild(because you don't want it to happen again.)
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06-09-2003, 01:12 PM
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Thanks Fishey, but it has the rubber version now. And what is the likelyhood that my original tranny (30K) and the replacement have the exact same problem in the exact same gear?
06-09-2003, 01:20 PM
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Is there a lot of back lash in the drive train? Put the *** end up in the air securly, put the car in gear, rotate a wheel back and forth in all gears and neutural. Make an approximation of how much the wheel can turn (in degrees) before it begins to turn the opposite wheeel. Take note of the difference between gears.
I had a shudder in 3rd only when on boost. I replaced the CV's and Clutch, no change. I just did the rear wheel bearings and hope that was the cause. Not sure yet since I have not driven it, but we'll see. Since it only happens in 1 gear, I would say it has to be after the differential. (CV, bearings, loose hubs)
I had a shudder in 3rd only when on boost. I replaced the CV's and Clutch, no change. I just did the rear wheel bearings and hope that was the cause. Not sure yet since I have not driven it, but we'll see. Since it only happens in 1 gear, I would say it has to be after the differential. (CV, bearings, loose hubs)
06-09-2003, 01:28 PM
#10
Race Car
Somebody on here told me a while back that the shudder in my early 944 was actually an issue related to the DME. Could this problem be related as well?
After work I'll find the link to the webpage I'm talking about, might be helpful since you've almost exhausted every other resource.
After work I'll find the link to the webpage I'm talking about, might be helpful since you've almost exhausted every other resource.
06-09-2003, 02:51 PM
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Z-man, yes, I do heel and toe, and when revs are matched there is very little of this shudder. But, if you are loping along in heavy traffic, or not exactly on rev, the thing goes ballistic. I had an 86 Normal 944 for over 10 years and 147K miles and it did nothing like this.
06-09-2003, 03:38 PM
#15
Race Car
Man sorry to hear about the problems. I think you did just about everything to track down the problem. I can think of only a couple of other inprobable causes. Have someone drive next to you while you downshift and see what's happening to your rear wheels. If you have bad suspension parts or shocks, uner engine braking, you may have vibrations. Another cause I have seen is exhaust too close to the torsion bar housing. During engine braking, the exhaust vibrates against the rear suspension causing vibration and sometimes noise. I had that happen to my 85.5 944 and the problem happpens mostly during downshift from 3rd to 2nd. Good luck.