924Board.org

[Duncan]

I have a bit of an issue with changing gear.
When I start the car the gear change is very smooth initially. However, if I have driven for a while, and the car is stationary for a traffic light and I engage gear, I hear a sort of 'clung' sound, but it is not difficult to move the shifter. If I have driven on the high way for a longer while, the 'clung' sound upon engaging gear becomes much louder/ After 5 minutes of the high way in city traffic the sound returns to its normal level.

What can this be? 1983 NA RoW with 230000 km Audi 5 speed tranny.
The clutch has been renewed recently and is correctly adjusted.
Also fly wheel end oil seal was replaced. Clutch disk is clean.
Clutch pedal is not very stiff. I noticed a lot of axial play when moving the portside flange of the gearbox.
The shop that has renewed the clutch suggests it is most likely something in the gear box.

Furthermore, if I am scouting for a replacement gearbox, how can you identify the year of production of the gearbox?

Thanks in advance,

Sincerely,
Duncan

[Smoothie]

For an NA, the last 5 digits of the transmission number code are the production date. The code starts with 2 letters -
("MD" for 5-speed Audi 1983 Europe/ROW with normal differential)
("4Q" for 5-speed Audi 1983 Europe/ROW with LSD)
- followed by a 2 digit production day, 2 digit month, 1 digit year.
Depending on year and location, the letter prefixes change, but the last 5 digits are always the date on NA transmissions (931 transmissions got a 5 digit serial number instead of a date).
Page 4 here explains the codes (332KB download) - http://www.geocities.com/p924tech/924.zip
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Smoothie]

On the clung -
I sometimes get something like that - not while shifting at speed on the highway, but after the transmission's warm and I throw it into reverse a little too quick after rolling forward. It'll make a clunk sound and feel like the gearbox jumps a bit, but that's a rare occurance. If it's a major constant problem, maybe change to a different gear oil. I've heard talk around here about synthetic gear oil (Redline?). It's more slippery and thinner and will make the gearbox somewhat louder - then again maybe a fresh fill of 85W-90 weight's appropriate. I don't know... If it's due for an oil change, you might try whichever's not in there now.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Duncan]

Thanks Smoothie,

I was also under the impression that I would need a gear box oil that
has higher viscosity when warm. Currently I run 80w90.
Is the viscosity at ''warmed up gearbox temp" of a 75w90 less than the viscosity of a 85w90, or both being **w90 the same?? My doubt comes from the fact that I imagine gear box oil does not get as hot as motoroil, or am I wrong ?

Do you think the play in the diff has anything to do with the 'clung sound'??

Thanks again.
Duncan

[Lizard]

depends on your tranny although make sure it is GL5approved.
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3 928s,

[CMXXXI]

[Duncan]

Thanks CMXXXI,


I thought that because the oil in the gearbox does not get that
hot, the 'cold' viscosity would be more relevant than the 'hot'
viscosity. How hot/warm is the oil supposed to get ?

Can you comment on this please?

[Smoothie]

I don't know exactly how hot it gets, but based on the fact that later 944 manual transmissions had oil coolers, it's easy to conclude that it does get hot. There are gear oils available that have higher second numbers than 90. Whether you want to experiment with that is up to you, but it makes sense that you should see some lessening of your symptoms with an oil that stays thicker at higher temps. For the same reason, synthetic gear oil might help because it runs cooler. Following is some relevant info -