[Darkstarexodus]

Well, this is my first post here at DSMTalk, though I've been a daily reader for a year or so. I just bought my 1990 TSI AWD 5sp. about 2 months ago and really love it. However, I have had some problems with shifting it. I've searched the board and not found anything that seems to answer my concerns.

When I first got the car it shifted fine, but within a week it was barely driveable for someone who was just learning stick. My dad could drive it but only with a lot of hassle. We replaced the clutch master cylinder and slave cylinder and the problems seemed to be solved. Of course, the tranny was still a bit notchy, but it's a DSM, what else is new?

Lately, however, I've been having a difficult time shifting into gear. With the clutch fully depressed, the shifter won't always go fully into the gate and will do so only when I let off the clutch just before the point of full engagement. This is most prevalent shifting into 1st at a light (I have to let the clutch out until the car is about to stall before it'll pop into gear) and so I wouldn't think that it's the synchros if I'm at a stop. It does, however, occasionally occur in 2nd and very rarely in 3rd (VERY rarely), 4th and Reverse. (Oddly enough, the only gear I have had absolutely no problems with is 5th . . . unlike some ppl)

About the clutch, it is a stocker (and the original, AFAIK, with about 120K on it). It does not seem to ever slip, even when at 5K+. Maybe it's going, but it's not a foregone conclusion, I guess.
Also, I'm running GM Synchromesh.

The most curious thing is that the problem is very intermittent (some days it shifts normally, the odd day it shifts so nice I think I'm driving an Audi...) and seems to occur more often when it is either rainy or hot and extremely humid.

If someone can offer some suggestions or solutions, I'll be very grateful. Thanks in advance, and my apologies for being long-winded.

 

[Blackboost]

Take a look at this article and check your clutch pedal (even if you don't have an ACT clutch because I have had to repalce the pedal assembly on stock cars): http://www.taboospeedshop.com/clutch_pedal_assembly.htm

 

[Darkstarexodus]

Many thanks, I'll have to check that out this weekend if I get a chance.

 

[MegaGS]

You might want to check all the cable brackets going to the shifter on the tranny. When I did my clutch I left 1 bolt out and it allowed the cables to move a bit, Shifting was horrible one week, beautiful the next, when I finally got around to looking at it I could have kicked myself. Doing the shifter mod on vfaq will help too maybe.

 

[AluH20]

My car is like that for reverse. You have to hold the shifter with some force onto it and back off of the clutch pedal before it pops into reverse gear. With my luck it's probably busted.

 

[markGSX]

My car is like that for reverse. You have to hold the shifter with some force onto it and back off of the clutch pedal before it pops into reverse gear. With my luck it's probably busted.

Mine does that too. So does reverse on my friend's 99 GS-T. It's normal.

 

[James92TSi]

My car is like that for reverse. You have to hold the shifter with some force onto it and back off of the clutch pedal before it pops into reverse gear. With my luck it's probably busted.

Sounds like the reverse brake synchro is worn out. The reverse brake synchro lines the gears up so they mesh when you go into reverse. You're having to let the clutch pedal out to rotate the input shaft so the reverse gears align... when the gears align, it pops into reverse. A new reverse brake synchro should fix that.

On mine, I always shift into 3rd before shifting into reverse in order to stop the input shaft so I don't wear out the reverse brake synchro. Going into any other gear stops the input shaft, so you don't get the crunch from the reverse brake synchro when going into reverse. That crunch is the reverse brake synchro having to stop the input shaft with its teeth.

Good news is, you can replace the reverse brake synchro with minimal effort. Pop off the RF tire and splash shield, drain the trans, remove the end cover on the trans, and reverse / 5th gear are right there. The reverse brake synchro is the one that just fell into your lap when you removed the end cover. Replace it, seal up the trans with grey RTV, and put it back together.

 

[91eclipsegsx16boy]

Sounds like the reverse brake synchro is worn out.

That's funny, when I had my tranny rebuilt they said there was no reverse syncro. If you try to put it in reverse with the car moving at all it will grind unless you perfectly rev match. So either the place that rebuilt my tranny doesn't know wtf they're talking about or didn't put a reverse syncro in on the rebuild lol.

-aaron

 

[James92TSi]

The shop is correct in saying reverse isn't synchronized.

The reverse brake synchro serves to align the gears when going into reverse... it is not meant to synchronize moving gears (like the synchros on the forward gears do), but simply aligns the gears so they mesh right (reverse is straight-cut, so it needs some help).

It is assumed that the car isn't rolling when you try to go into reverse (output shaft is stopped), and that the clutch is disengaged (input shaft is stopped or at least disconnected from the flywheel). By that line of thinking, it shouldn't be necessary to synchronize any moving parts when going into reverse, since the input and output shafts are both stopped.

If the car is moving when going into reverse, it will crunch.. there's no way around that.

 

[91eclipsegsx16boy]

The shop is correct in saying reverse isn't synchronized.

The reverse brake synchro serves to align the gears when going into reverse... it is not meant to synchronize moving gears (like the synchros on the forward gears do), but simply aligns the gears so they mesh right (reverse is straight-cut, so it needs some help).

It is assumed that the car isn't rolling when you try to go into reverse (output shaft is stopped), and that the clutch is disengaged (input shaft is stopped or at least disconnected from the flywheel). By that line of thinking, it shouldn't be necessary to synchronize any moving parts when going into reverse, since the input and output shafts are both stopped.

If the car is moving when going into reverse, it will crunch.. there's no way around that.

Gotcha, from what you describe, I blieve they replaced that part . Thanks for clearing that up.

-aaron

 

[MegaGS]

If the car is moving when going into reverse, it will crunch.. there's no way around that.

I have that issue with my reverse as well, it doesn't grind, but won't go in unless I either a) try numerous attempts or b) let the clutch out a little.

I haven't noticed grinding in mine, the other day I was stuck in mud and had to rock the car, it was moving forward slowly and went into reverse fine Here's at least one exception to your thinking.

 

[Darkstarexodus]

Well, I've already tightened the shift cables, so that's not the problem. I brought my dad out to drive the car to see if he could troubleshoot with me, and funny enough, the car shifted absolutely perfect for him. Of course, I was boggled by this, but when I took it out later last night it was just fine for me too. . . . Odd....

 

[Burg]

Sounds like your master cylinder is letting some moisture into the system. Or possible the master cylinder is not pumping properly all of the time.

 

[MegaGS]

Sounds like your master cylinder is letting some moisture into the system. Or possible the master cylinder is not pumping properly all of the time.

Yep, check for leaks under the dash.