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Join Date: Oct 2002
Location: Norfolk, VA
Posts: 38
Red face Disturbing shift issue, 87 944S

Well, this was an eye-opener...

I've been noticing my 5-speed shifting action getting increasingly stiff over about the past week or so, but only while underway. Temperature does not seem to matter, and there are no unusual noises coming from the rear of the car. Today, coming back home down the interstate, I came up the on ramp and accelerated to get out of the way of a truck bearing down on me... I was in fourth at the time. Got up to over 70, went to grab 5th...

and I couldn't get the damn thing into gear! Couldn't downshift, either! WTF!

I immediately wove my way thru traffic to a convenient offramp, braked to a stop, and naturally the shifter went thru the pattern with no trouble. Cursing ensued. Once in first, acceleration was smooth and troublefree (as it was previously)... but I did note that the higher the revs when I attempted to shift, the more resistance I encountered when doing so. I got home fine by shifting at 3200 the whole way home.

Vitals:

- Recently installed clutch (around 13,000 miles ago) to include new slave and master cylinder, heavier sprung plate (no rubber bushings), etc. Replaced by a well-qualified Porsche mechanic before I purchased the car last August.
- Shifter action has been somewhat vague/sloppy for a while, I have replaced the bottom bushing but have not gone through the rest of the shift linkage to check it.

So how about it, guys? Does any of this sound vaguely familiar? One of the first things on the list is to track down a 17mm allen socket to get the upper plug out of the tranny and check the fluid; I noted some dampness back there, smelled like hypoid. Could it be something as simple as being low on fluid?

I went thru the archive but didn't see anything that seemed to match this situation; any assistance you guys can offer would be GREATLY appreciated!

Thanks in advance,

Lynn
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Old 05-11-2003, 11:59 AM
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Quote:
Transmission Synchro Hubs

The synchro hubs are the dog-teeth that are mated with the various gears, and engage with the slider. Dog teeth become worn after the synchro rings wear out, making it difficult to get the transmission into gear, and keep it there. Sharpen up your canine with a new set of teeth, and get back your shifter.
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Old 05-11-2003, 12:26 PM
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Handle hitting frame?

It doesn't seem to be. There is just significant resistance to getting any gear to select when at speed. I had a 280zx ages ago that had bad synchros, and it doesn't feel like that at all... yeah, I know, this is a different *and better* car, but still- the fact that there are no mechanical noises associated with this is definitely puzzling me.

Thanks,

Lynn
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Old 05-11-2003, 02:57 PM
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When was the last time you change out the tranny fluid? Last summer I put 85W gear fluid in the tranny. It was hot that summer. While I was working on my car winter hit. When I got the car running I noticed when the tranny was cold and the oil was at it's thickest, it was hard as hell to get the friggin thiing into gear. There were no noises what so ever. Once the tranny warmed up shifting was flawless and the tranny was quiet. Maybe you have really old thick tranny oil up in there? But then again you said you have more trouble shifting in the higher revs?!?!? It is still hard to shift once the tranny is warm? Is it hard to shift when the tranny is cold? Is it through all the gears? Has the tranny ever popped out of gear?
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Old 05-11-2003, 04:46 PM
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Aaaaaaugh!! So many questions!!! :)

Ok, in order of appearance...

Maybe you have really old thick tranny oil up in there?
- Maybe, I don't know... I don't know if it was changed when the clutch was done last year (bought the car after the work was done)

But then again you said you have more trouble shifting in the higher revs?!?!?
- Correct. In thinking this through, the shifting did not improve until the speed bled off somewhat; I had jumped on the clutch and let the engine revs bleed down while still coasting at a good clip, and attempted to get into 5th, then 4th, then 3rd, all to no avail.

It is still hard to shift once the tranny is warm? Is it hard to shift when the tranny is cold? Is it through all the gears?
- It is not temperature dependent... the stiffness was present as soon as I fired up the car and started to move. And strangely, 5th did not appear to be affected until that disconcerting moment today.

Has the tranny ever popped out of gear?
- No, it has not.

Probably doesn't get us any closer, but perhaps this'll help sort out what it's NOT... ?

Thanks much,

Lynn
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Old 05-11-2003, 05:49 PM
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This symptom is what has prompted me to change the clutch in my '87 924S. Not sure if the 944S uses the same rubber center or not, but what is happening with my old clutch is that if any great torque is applied to it (i.e. anything remotely resembling spirited acceleration) then the clutch binds on the driveshaft splines and it does not disengage fully. This also happened to someone on another board and they were told to replace the clutch too.

Aaron
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Old 05-11-2003, 06:19 PM
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Very interesting..

First thing I would check is he fluid level. If the box is wet and it stinks of hypoid, you definately have a leak - generally they leak from four places - the axleshaft flange (what the CVs connect to), the main shaft, or the rubber seal at the end of transmission case

Axleshaft flange - can fix with tranny in the car, rear seal - if you can get at it, you can do it in the car - need small hands though

Would not bother too much with the front seal unless it is a large leak as the transmission will have to be dropped to get at it.

Fluid may have small amounts of silvery dust in it when you change it - completely normal. Chunks are bad.

Also, would check the shift rod coupling (should be right above transmission, drivers side) - make sure the bolt is there and tightened down properly - that bolt is supposed to have a safety wire - many don't anymore.

Moving to the passenger compartment, check the shift rod - shift lever connection - they wear over time, the shift lever will need to be replaced, the shift rod itself can be drilled out and have a small bushing installed to bring it back up to speed. Do a search of the website, FR Wilk had a good how to article on it - search for the thread "Shifting Improvements"

Check clutch pedal - does the pedal have the correct amount of free play? Shouldn't be a factor for what you describe, but want to eliminate all possibilities at this point.

All of the above are DIY jobs that can be done in an afternoon for less than $100 in parts.
If all of the above check out properly and you are still having the issue, it is time to consider internal problems (synchro rings or synchro hubs)

AFJuvat
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Old 05-11-2003, 11:01 PM
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Thanks, AF...

Your suggestions reinforce my suspicions, and I will check all of the above ASAP; need to try and find that 17mm allen today too. The shift lever is a factory replacement item (it still has the parts inventory tag on it, dated 89 or 90), but I don't know when it was put in. I will certainly investigate it, though!

Thanks once again for your very helpful input.

Lynn
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87 944S, Guards Red
Member of the Order of the Bent Valve

My other car is ... oh wait, I don't have another car.

Chicks dig Messerschmitts.
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Old 05-12-2003, 03:56 AM
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