G50 Issue - Monkey Needs Help

[Porsche_monkey]

The Monkey is stumped. First time with a G50 car and now this:

P-car #2 ('89 G50 cab) has been sitting for about two years. After getting it started again I now find I can not get third gear when I am driving.

Sitting at idle the G50 will go right into third no problem. I do not think this issue was there when I parked th car two years ago, I think it is related to the long time it spent idle. Not 100% sure of that though.

I am guessing the synchro has jammed up (rusted while sitting?) and is preventing me from shifting 'on the fly'.

I am tempted to drain the fluid and look for 'evidence', maybe put in new synthetic fluid and see what happens.

Suggestions?

[Hendog]

I would say draining and filling with new gear oil (synthetic) is the right place to start. Otherwise I have no wisdom to impart...

[wildcat077]

I replaced the fluid on my recently acquired 89 Coupe with Quaker State 75W140 synthetic and find it takes around 10 to 15 kilometers of driving before it starts to shift smoothly... After the oil warms up it shifts better than the original OEM oil !
Being from Canada there's lots of it at your local Canadian Tire ... lol

[GaryR]

As it only happens when driving I would look at the tranny mounts also. The oil change would be a (fairly) easy 1st step.

[Peter Zimmermann]

Have you tried to put the car in 3rd, at idle, and drive away in that gear (from a stop) to make sure it really is in 3rd gear?

Please consider the above post about 75W/140 trans oil, that is not permitted for use in your car. You will be better served sticking with 75W/90 synthetic gear oil - I prefer Super Three Star Kendall synthetic, if you can find it in your area.

[Paulporsche]

Let me know if you need some shop assistance.

[LakeCleElum]

Will it do into 3rd if you "double-clutch'? That would indicate if the syncro is good or bad....

[aj88cab]

As stated above the 75W140 gear oil is not correct. 75W90 for sure.

You may also want to take a look at the shift linkage items circled in the diagram below. A problem with any of those could result in poor shifting. Items 2 & 10 are common wear items.

Good Luck, Andrew

[Porsche_monkey]

Originally Posted by Peter Zimmermann

Have you tried to put the car in 3rd, at idle, and drive away in that gear (from a stop) to make sure it really is in 3rd gear?

Yes, third gear is there. I can start in third, I also got it to shift into third once at very low speed. The rest of the time I can feel 'grinding' if I try to force it.

Originally Posted by Peter Zimmermann

Please consider the above post about 75W/140 trans oil, that is not permitted for use in your car. You will be better served sticking with 75W/90 synthetic gear oil - I prefer Super Three Star Kendall synthetic, if you can find it in your area.

I was not planning on using anything that thick. My 964 G50 is stiff enough in cold weather with 75W90.

Originally Posted by LakeCleElum

Will it do into 3rd if you "double-clutch'? That would indicate if the syncro is good or bad....

I have not tried double clutching. Will try this afternoon.

Originally Posted by aj88cab

You may also want to take a look at the shift linkage items circled in the diagram below. A problem with any of those could result in poor shifting. Items 2 & 10 are common wear items.

Good Luck, Andrew

I do not think it is a shifter, a mount, or a linkage issue. Pretty sure it's 'inside the box'.

[Porsche_monkey]

So as of now:

- I can start in third, no issues there, third gear works from a stop.

- I can not shift into third on the fly, even if I double clutch. I can feel the gears grinding if I try to force it.

Prognosis?

[aj88cab]

Failing clutch fork or shaft?

[Porsche_monkey]

Originally Posted by aj88cab

Failing clutch fork or shaft?

I do need a new clutch. All the 'action' is in the top 1/2".

Unrelated?

[Peter Zimmermann]

Originally Posted by Porsche_monkey

I do need a new clutch. All the 'action' is in the top 1/2".

Unrelated?

I would guess that if the clutch was the culprit other gears would be having the same engagement problem. A synchro can't fail while the car is sitting unused, but it could have been right at the point of failure when you parked the car. With your latest info I'll bet that the trouble is internal. Make sure that you have a good puller with a variety of different length jaws!

[KTL]

Sounds like badly damaged gear engagement teeth. If you can get them aligned when at rest, but cannot at speed, seems like the teeth are boogered. I have a hard time describing what the operating sleeve/teeth assembly looks like. It's not what most people recognize from the 915. The G50 Borg-Warner/Getrag gear engagement system is quite different in it's design

RE: clutch action occurring in the top 1/2, that's common. The G50 clutch engages really high on the pedal travel.

[Porsche_monkey]

I guess this winter will be G50 education time. Cha ching I am guessing for parts.

I can last the summer without third gear.

[Peter Zimmermann]

Just curious, how many miles are on the trans?

[Zeke]

Given the symptoms, can you shift into 3rd on the fly by matching revs to speed? Coming out of 2nd, let the throttle off ever so slowly so the RPM's just drop off little by little. Keeping pressure on the shifter would allow the trans to engage in 3rd at the correct RPM to ground speed.

If this works, the trans is fine, the clutch is not.

[Porsche_monkey]

Originally Posted by Peter Zimmermann

Just curious, how many miles are on the trans?

Lots. 150,000.

[Peter Zimmermann]

Originally Posted by Porsche_monkey

Lots. 150,000.

Probably a synchro, but I'll bet it costs lots less to fix than the clutch replacement. G 50s are over-engineered and almost bullet-proof, it might need nothing more than a couple of synchros/sliders.

[Porsche_monkey]

Originally Posted by KTL

RE: clutch action occurring in the top 1/2, that's common. The G50 clutch engages really high on the pedal travel.

My 964 G50 is exactly the opposite, all in the bottom 1/2, the way I like it.