Newbie

I'm based in the Uk and looked at a late 1988 Carrera 3.2 Sport Coupe yesterday. The car is in excellent condition and has a fully documented 44000 miles. My only concern is some gearbox noise on initially pulling away from rest in first, and evident when tricking along at low revs in 2nd gear. It has the G50 gearbox.

All of the cars I've looked at have exhibited some gearbox noise when the drive is taken up. Guess I'm looking for some reassurance from those who have more experience than I.

Anyone share their thoughts?

Thanks

Michael Ghia

The G50 does tend to give some chuntering (if that's a word!) from very low revs, all the G50 3.2's I've driven have done it.
I'd have the Gearbox oil changed before you buy it just in case but so long as it shifts ok...
Mike Ghia

Newbie

Thanks Michael.

Your description matches what I've felt. The car is in such good original condition that I have agreed to buy.

At what mileage would the oil normally be changed? Although this is a bit irrelevent on a 15 year old car.

Guess I'll just budget for a fluid change - Mobil 1 seems to be the favourite for this box (?).

Michael Ghia

Hi,
I'm in Florida at Gunnar and not near my books or I'd look it up for you. Someone here should be able to give you the low down on service intervals.
Yes Mobil 1 for the G50
MG

ron mcatee

Newbie, I switched to Mobil 1 in my 88 Carrera and it quited down considerably and also the shifting is much smoother. I recommend changing the tranny oil every 35,000 miles.

Newbie

Thanks all for the replies.

Thinking of getting a specialist to look at it - I suppose the noise on drive take up is of more concern. Anybody know what causes it with the G50 box? Car is 1988 model.

Is the gearbox oil a relatively easy DIY job? (Quite used to getting my hands dirty!)

Michael Ghia

Some gearboxes are just noisey... the other thing is when a gearbox starts to get old, and the bearings get worn, the clearances change slightly and create noise and it's almost impossible to get rid of it once it's there.

Changing the oil is messy and it stinks!! I would pay Machine Mart a visit and buy a hand pump (vertical type) which comes with a tube which you can stick in the hole in the side of the gearbox. Then atleast you're not putting the oil in in 1/2 litre cans upside-down and covering yourself and the floor in the stuff!
I think the pump is only about 30 pounds or so.
There is a drain plug and a level plug. Make sure the car is level and fill it through the level plug until it's just pooring back out and it's right.

MG

Bill Gregory

Another point - ensure you can undo the fill plug before you drain the oil out.

1FastRedSC

Also might be worth noting, my 915 makes noise in 5th and 3rd, only under load. Had the gears inspected before i put the box back together and was told they are in excellent shape. So i've come to the conclusion, that sometimes gears just wear together in a manner that creates noise when the teeth rub against eachother. Could be the bearings as well, but there's evidence of my car being tracked a lot before i bought it, so logic would say that 3rd and 5th were probably the ones used the most. 3rd's used a lot on the track and 5th is used a lot on the highway. Just my .02

sschmerg

My '88 makes the same noise you describe when starting in first gear. My car only had 21k miles on it when I bought it, and was in concours condition both mechanically and cosmetically. I asked a tech about it back when I first brought it in for service, and he said it was normal. I've only driven two other G-50's and they also made the noise, but I'm not sure if they all do. I know there were some updates Porsche made with the '89 MY, so perhaps those were quieter.

-Sean

ron mcatee

The gear noise can also be caused by increased clearance between the gears. This is sometimes so minute that it falls within the factory specs. What you hear is air in between the gears and not a potential failure of the gears. Only a tear down will tell you if the gears are within specs. My 88 Carrera doesn't make noises now that i've change to the Mobil 1 fully synthetic fluid. It did make some noise when I had the 75w90 Dino fluid in it.

Newbie

Thanks to everyone! Most helpful.

I look forward to collecting the car in just over a week's time - really looking forward to it. Whilst I was gutted to sell my Lotus, owning a 911 Carrera will be a dream fulfilled!

I shall take your advice and change the transmission fluid to Mobil 1 75w90.

CN

I get that funny sound at very low RPM in first gear. It happens if I fully engage the clutch at about 800-1200 RPM. To me it sounds like a vibrattle for lack of a better term.

Regards,

dial911

915's aren't that quiet if you lug them.
And the G-50's growl in a similar fashion.
The infamous rubber centered clutches attempted to dampen some of this noise.
Vibrattle? A good term!

Ed Bighi

My 88 makes the same noise. As long as it shifts fine, everything is normal.