gearbox problem
Thread Starter
Instructor
Joined: Mar 2002
Posts: 136
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From: Maidenhead U.K.
gearbox problem
I am new to this message board and i am having auto gearbox problems on my 1984 928 s2,97,000 miles. The gears are not changing well at all.On excelleration they do not engage correctly and seem to slip.The other day i was on the motorway and it would not go into third of forth gear.I have checked the fluid and it is at the correct level and clean. Is there anyother points that i can check or is the auto transmission shot. Any answers to my problem would be great.
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Joined: Oct 2001
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From: Bend, Oregon
Hi Tim:
Before you drive the car much more and risk mechanical damage, take the first step and change the fluid. The auto trans in the 928 is one of those things that often gets left off of the PM list because they tend to work pretty well. I think the service interval recommendation is 25k or 30k, and it's not a huge job even for us DIY owners.
The old fluid fails due to heat for the most part. Telltale is a faint burned fragrance, followed by discoloration if the problem gets severe. New ATF is a pretty pale red, and is translucent.
As the trans wears, little bits of clutch plates, and hopefully not much else, come loose in the fluid. They should be filtered out by the filter in the pan, but it's possible that one would get by that and jam up the works, causing the symptom you describe. Replacing the fluid may cause any stray bits to be removed.
There's also the issue of how you verify level in the gearbox. To get an accurate reading, the car needs to be on level ground or a level lift, at normal operating temperature, engine running, cycle through all the gears, end up in park or neutral, and then check the level in the little bottle. If the level is checked at any other situation, you will see a false reading that's higher than what the box really needs. Symptoms are very similar to what you are describing.
I'd go through the change excercise before spending on other diagnosis.
Hope this helps!
<img src="graemlins/yltype.gif" border="0" alt="[typing]" />
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Before you drive the car much more and risk mechanical damage, take the first step and change the fluid. The auto trans in the 928 is one of those things that often gets left off of the PM list because they tend to work pretty well. I think the service interval recommendation is 25k or 30k, and it's not a huge job even for us DIY owners.
The old fluid fails due to heat for the most part. Telltale is a faint burned fragrance, followed by discoloration if the problem gets severe. New ATF is a pretty pale red, and is translucent.
As the trans wears, little bits of clutch plates, and hopefully not much else, come loose in the fluid. They should be filtered out by the filter in the pan, but it's possible that one would get by that and jam up the works, causing the symptom you describe. Replacing the fluid may cause any stray bits to be removed.
There's also the issue of how you verify level in the gearbox. To get an accurate reading, the car needs to be on level ground or a level lift, at normal operating temperature, engine running, cycle through all the gears, end up in park or neutral, and then check the level in the little bottle. If the level is checked at any other situation, you will see a false reading that's higher than what the box really needs. Symptoms are very similar to what you are describing.
I'd go through the change excercise before spending on other diagnosis.
Hope this helps!
<img src="graemlins/yltype.gif" border="0" alt="[typing]" />
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Thread Starter
Instructor
Joined: Mar 2002
Posts: 136
Likes: 0
From: Maidenhead U.K.
i have done an oil change and the car runs much better not 100 percent but better. ive got a few other parts to check not before i pull out the box as this looks like a long job