2nd gear crunch - 986 Forum - The Community for Porsche Boxster & Cayman Owners

ike84 · 08-27-2021, 06:47 PM

Upshifting from 1 to 2 in my car has always been touchy. When done perfectly it is smooth, but it is more difficult to nail than the other gears which I get perfect 99% of the time. The roughness has always been with rev matching and clutch engagement though, never with the shift itself.

Recently though, over the last few weeks, I will notice an occasional "crunch" feeling in the shifter when I go into second. This is true on upshift and downshift. It does not happen every time and despite my methodical attempts to do so, i have not been able to pinpoint specific worsening or relieving factors.

Gear boxes are a weakness for me. Help a brother out. Do I feel this just because I have a short shifter now and everything is "amplified"? Do I need to change fluid? If fluid change didn't work then consider 2nd gear detent mod? If this doesn't work, plan on using it for my next boat anchor?

Fwiw, I don't pussy foot around on shifts. I don't slap shift or side step the clutch, but I drive it like I stole it every day of the week (I've heard this is good for the IMS

).

Sent from my SM-G970U1 using Tapatalk

piper6909 · 08-28-2021, 06:07 AM

Sounds like your synchro is going.

Gilles · 08-28-2021, 10:22 AM

Quote:

Originally Posted by piper6909

Sounds like your synchro is going.

Agree with Piper, but you may want to replace the tranny fluid first to see if improves, like the saying 'before brain surgery try an aspirin'..?
If not, you may want to send it to CMS to replace the 2nd gear synchro

ike84 · 08-28-2021, 12:47 PM

Thanks guys. How does does that service tend to run? I wondered there are any diy tutorials out there.

Sent from my SM-G970U1 using Tapatalk

husker boxster · 08-28-2021, 01:37 PM

There are DIY tutorials out there. Not a difficult project, with your abilities you'll not have trouble doing it. Top tip - remove the side entry port before draining all your fluid and then finding out you can't open the fill port.

However, I'm not holding out positive results for you. You're headed down the same path I took. Changed the trans fluid and it didn't help. I had a 3-2 downshift crunch, but basically the same issue as a 1-2 upshift - 2nd gear synchro issue.

I shipped my trans off to AZ for a $2K repair - $1300 for parts and $600 labor. Then a pic arrived of the ring & pinion with a chunk missing from a tooth. Add another $2K. Then an examination of the 3 & 4 synchros added another $2K. Now I'm w/in a $1K of a $7K reman. Cha-ching, cha-ching, cha-ching.

Hope you have better luck.

jaykay · 08-28-2021, 04:31 PM

In my mind just resistive/ crunch feeling is different from a crunch sound coming in on top of it.

Do you have an experienced / trust worthy Porsche specialist near you? I would have them investigate what you are feeling?

Investigate the cost vs benefit of the second gear detent; CMS shift arrester and synchro service against the recommendations of specialists/opinions

I put in a model 2nd gear detent to stave off problems sometime ago. Feel wise it gives a longer engagement path for rear gate positions, preventing "pop out". IIRC It did not smooth out the shift action and I don't believe it would help worn synchros.

Different fluids will affect synchronization but in these boxes I don't think there is much leeway for experimentation. I have Miller in there right now and would like to find the Devac or Mobil Lube PTX 75W-80 and see how that feels.

I have only worked with six speeds and they very stiff shifting transmissions. I also found double de clutch downshifts into second can really smooth things out you can do it going up too but of course it feels and is slower. I must say that can nail this completely on my old Jeep but not on the Boxster as the wonkier high clutch engagement always throws me off....I guess I have to get in there an pull the helper spring out.

ike84 · 08-28-2021, 04:34 PM

Quote:

Originally Posted by husker boxster

There are DIY tutorials out there. Not a difficult project, with your abilities you'll not have trouble doing it. Top tip - remove the side entry port before draining all your fluid and then finding out you can't open the fill port.

However, I'm not holding out positive results for you. You're headed down the same path I took. Changed the trans fluid and it didn't help. I had a 3-2 downshift crunch, but basically the same issue as a 1-2 upshift - 2nd gear synchro issue.

I shipped my trans off to AZ for a $2K repair - $1300 for parts and $600 labor. Then a pic arrived of the ring & pinion with a chunk missing from a tooth. Add another $2K. Then an examination of the 3 & 4 synchros added another $2K. Now I'm w/in a $1K of a $7K reman. Cha-ching, cha-ching, cha-ching.

Hope you have better luck.

That's what I'm afraid of also. I have no reason to think that there will other problems other than to say that I'm sure there will be lol.

I was thinking about swapping in a used 6 speed. It seems that these are sturdier transmissions overall than the 01a 5 speeds. I think I would need new axles to go with it. I know the bolt pattern is different for the two, so I wonder if there are enough common holes that it will mount up.

Off to the forum archives I go...

Sent from my SM-G970U1 using Tapatalk

ike84 · 08-28-2021, 04:41 PM

Quote:

Originally Posted by jaykay

In my mind just resistive/ crunch feeling is different from a crunch sound coming in on top of it.

Do you have an experienced / trust worthy Porsche specialist near you? I would have them investigate what you are feeling?

Investigate the cost vs benefit of the second gear detent; CMS shift arrester and synchro service against the recommendations of specialists/opinions

I put in a model 2nd gear detent to stave off problems sometime ago. Feel wise it gives a longer engagement path for rear gate positions, preventing "pop out". IIRC It did not smooth out the shift action and I don't believe it would help worn synchros.

I've never heard any noise coming from the transmission, bit my car is quite loud and I'm not sure I would hear it if it were subtle.

The closest p-car indys are 3 hrs away. I used to live right down the street from Pat Williams, boy do I miss those days lol.

That is my understanding of the 2md gear detent mod as well, that it helps prevent popping out of gear. I've never had that problem, but I had read a few posts that said that it fixed the crunch sensation while shifting.

Sent from my SM-G970U1 using Tapatalk

ike84 · 08-28-2021, 05:40 PM

Ok, it looks like a 986 6 disc swap is out of the question. Clutch line, spacer cylinder, axles, upright, wheel carriers, the whole shebang. Not worth it.

I did find a part from brad Roberts about putting a 987 boxster s 6 speed in the 986 base, but he didn't elaborate and I can't seem to find documentation of anyone doing it.

Does anyone know about this swap?

Sent from my SM-G970U1 using Tapatalk

itsnotanova · 08-29-2021, 04:30 AM

986/996 6 speed's are the transmissions that generally have detent problems. You have a 2.7 5 speed correct? There's no need to try other transmissions as the 2.7 5 speeds are dirt cheap. 2.5 5 speed transmissions are a different story.

The 987 6 speed can be used in a 986 with custom axles(986 axle with 987 inner CV's) and 987 transmission mounts. I've never put one together but I've seen some boxster race cars use the 987 because of the belief the 987 is stronger. It was a theory that lasted a few years but I don't think anyone is doing it anymore. I have plans to use a 987 6 speed in my 986 but that's because I plan on swapping in an Audi 2.7. Otherwise I wouldn't suggest using a 987

ike84 · 08-29-2021, 05:31 AM

The logic for the 6 speed is a "while I'm in there" approach - if I'm gonna swap the tranny, might as well drop some extra coin and get one that is actually worth a damn.

I was looking at parts last night, it looks like a used 986 5 speed can be hadfor $500, whereas a 987 6 speed can be had for $2500. 5x the cost, but maybe worth it by avoiding a few more 01a 5 speeds in the future?

Sent from my SM-G970U1 using Tapatalk

itsnotanova · 08-29-2021, 02:16 PM

I can't believe I'm defending the five speed but here it goes. As long as you don't do any clutch drops the 5 speed can handle up to around 300hp. Doesn't have the detent problem the 6 speed has. Granted you're going with the 987 6 speed. I don't think those have detent problems but I'm not really involved in the 987 world much. The five speed is not only cheaper, so are the axles and I think the LSD. You'll also have to add in the cost of S rear uprights and brakes towards your swap. The 6 speed will be heavier and I wouldn't be surprised if it uses more horsepower. I hear the 5 speed is easy to rebuild if you choose that route. I personally would just buy another used one before I rebuilt a 2.7 five speed.

ike84 · 08-30-2021, 06:24 AM

Quote:

Originally Posted by itsnotanova

I can't believe I'm defending the five speed but here it goes. As long as you don't do any clutch drops the 5 speed can handle up to around 300hp. Doesn't have the detent problem the 6 speed has. Granted you're going with the 987 6 speed. I don't think those have detent problems but I'm not really involved in the 987 world much. The five speed is not only cheaper, so are the axles and I think the LSD. You'll also have to add in the cost of S rear uprights and brakes towards your swap. The 6 speed will be heavier and I wouldn't be surprised if it uses more horsepower. I hear the 5 speed is easy to rebuild if you choose that route. I personally would just buy another used one before I rebuilt a 2.7 five speed.

I wouldn't mind rebuilding it, if I knew how. My knowledge of transmissions is comic book level unfortunately, and the FSM (not surprisingly) is a bit confusing to say the least.

The flip side of that coin though is buying another one is a total crap shoot, and with my luck the "new to me" one would be worse than this lol.

Sent from my SM-G970U1 using Tapatalk

ike84 · 08-31-2021, 12:33 PM

Over the past two days I have really been trying to find a pattern to the crunch. What I have noticed is that at cold start it is completely absent and all shifts are butter smooth. When the system warms up though the crunch occurs and shifting in general seems to be rougher (except for double clutching, which is butter smooth regardless of gear and temp).

My hope is that this is fluid related. If the crunch isn't there at cold start the synchro may still be ok. It may be a long shot be we will see. I ordered fluid today and will use this as an excuse to install my transmission cooler setup over the next week or so. I'll keep everyone updated once she's back up and running.

husker boxster · 08-31-2021, 10:03 PM

Sorry to pee in your Post Toasties, but my trans ran better in winter than summer.

ike84 · 09-01-2021, 07:56 AM

Quote:

Originally Posted by husker boxster

Sorry to pee in your Post Toasties, but my trans ran better in winter than summer.

knock it off damn it!

just kidding.

we will see what happens. im going with a thicker fluid than the mobilube spec (flame suit on, have at it) so i'm hoping that will make a difference. but we shall see...