Hi!

Here's a problem I didn't find in the archives. 964, '93, 3 litre. Only 160000 kilometers.
Been sitting for three years, now back in service....or would be, if it wasn't that it drives perfectly until it is warm (10 minutes or so), then the gearbox quits - no traction. Let it cool down, and it is ok again. I changed the fluid, but it didn't help.
Am I overlooking the obvious, or do I need to swap gearbox?'

tia, Jens

Dear Jens,

May this find you well. Did you flush the trans fluid? That is, did you remove all of the fluid in the trans, by introducing clean, fresh fluid, or did you simply drain the pan?

Draining the fluid in the pan removes at most one-third of the total contents (about 9 quarts/8.5 liters).

I'd recommend you:
(a) Pull and trans pan and clean it until it is surgically clean
(b) change or get changed, the trans filter
(c) flush the tranny, using standard trans fluid (Dexron III Mercon). It should take about 3 gallons (11+ liters) completely to remove all of the old fluid. See the FAQs, under FEATURES above, for this procedure.

See if that helps. If it does, then wait for 300-400 miles (500-650 Km) and re-flush with synthetic trans fluid (e.g., Mobil 1).

It sounds to me as if there is dirt/particulates in the pan. When the trans runs, the dirt is moved through the system, plugs up a valve, and the trans stops working. When the trans pump is turned off (which happens, when the engine shuts down), the dirt slowly floats away from the choke-point, and the tranny will work.

Before you put in a new trans, have it flushed, as above.

Post back on the results. Hope this helps.

Yours faithfully,

spook

Thanks mr Spook, I will follow your advice and try to clean it out. Will be back with a follow-up. Let's hope for the best.
L8r, Jens

Dear Jens,

May this find you well. Is the trans fluid clear red or is it orange/brown/black or cloudy (any color)? If it is cloudy, that is a sign of water infiltration. If water has been in the trans casing for a long time, it may have dissolved some of the clutch plate material (the adhesive is water-soluble). If that is the case, you likely will need a new trans.

No one should rebuild an AW71 (cost would be >US$1K). The AW71 trans can be had at a salvage yard for little money (US$200-300, in most parts of the US), because they rarely fail, and so are not in demand. A low miles car that ends up in a salvage yard likely will have a perfectly serviceable trans. Flush it out thoroughly, and you're good to go.

Hope to hear good news.

Yours faithfully,

spook