Transmission, Automatic

Stuck in First Gear

Stuck in First Gear

The Car - 928S 1981 Auto Euro
The auto box has been changed within the last 5000 miles
With what I know not. (PO)
Current temperatures are below freezing.

The Problem - Car will only drive in 1st gear even when D or 3 are selected. In D it will not move up to the gears 2nd 3rd. Selector will select and use P, N, R.

Recent History
Car does less than 5000 miles per year.
Gear Selector Cable replaced 3 months ago.
Oil changed in gearbox by non Porsche mechanic 2 months ago
Gearbox oil filter not changed at the time.(I have this item now)

The night before the car had been doing 130
(If anyone asks it was KM/H, if you don't ask it was MPH)
then we came to a slow area. Car felt as if the handbrake was on.
There was a resistance in the car somewhere to forward movement.

Next day car drove OK for maybe 10 miles then started switching between 3rd and 2nd at a constant speed. Then the car decided that it only liked 1st gear which is what we drove home in. Following day the car still likes 1st gear but doesn't like 2 or 3(D)

Could someone answer the following questions please.

1. What mechanism controls auto gear changes
2. Where is this mechanism situated.
3. What are my courses of action excluding handing it over to the local Porsche agent.

Many Thanks

Colin Hughes
928S 1981 Auto Euro 3 Speed (1Speed). Guards Red


1. A complex blend of control positions, engine speed, throttle position, road speed and engine load.
2. All over the car.
3. Buy or borrow the factory shop manual set.

Once you have the shop manual set:
1. Check governor pressure. If the pressures are correct, go to step 3.
2. If the governor pressures are incorrect, clean and service the centrifugal governor.
3. Disassemble and clean shift housing. If this does not solve the problem, replace the shift housing.

There is NO WAY that you should attempt this without the manuals.

If you take the car to a shop, you would probably be better off at a Mercedes shop, since the transmission is a Mercedes design.

Wally Plumley
928 Specialists

My car had an intermittent failure to shift out of 1st range. After a day or so the failure became permanent. The solution turned out to be simple: Upon removing the bottom pan my trusty mechanic discovered that the spring on the accelerator return had broken. He simply replaced it. Along the way I also learned the following: My car has approx 100,000 miles on it - (not on the odo, it stopped prematurely at 70,000 miles, as most of you know is typical). My guy says that a serious failure of this "robust/well-built" trans at this number of miles is unusual, unless the car had been abused. It turns out, as is apparently common, internal rubber seals have deteriorated, causing tiny bits of the seals to become suspended in the trans fluid (a good mech can read the fluid for this condition). Try the following solution before going for a rebuild: Do a POWERflush of the trans fluid, (Note: a normal trans fluid flush is not particularly effective - in a normal ( non-power flush) about 1/2 of the fluid is retained in the torque converter resulting in only a 50 % flush. After a powerflush, (the trans shop needs a special machine that uses pressure to get more of the old fluid out, they say approx 90 %), and using a good trans fluid conditioner, (to soften up the seals), you have a good/reasonable chance to have several more years of good trouble-free transmission service. In our city, the cost of this power flush is about $80 US, so not much of a gamble considering the expensive alternatives.

Hope this all helps somebody,
Al Paton

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