Automatic Tranmission Problem- Car Not Shifting to Third

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Automatic Tranmission Problem- Car Not Shifting to Third

Postby cboyne » 04 Sep 2006, 01:07

I am looking at a 1980 Pontiac Acadian right now and I am hesitant to buy because of a Transmission problem. The car shifts great from 1st to 2nd but it will not shift into 3rd gear and you can't go much faster then 40 km/h on a flat without the car over revving.

The owner has had the car parked for a little over four months. He said the transmission was great before it was parked. Someone mentioned to him that the car might just need a new transmission screen and new tranny fluid.

ANY THOUGHTS? I don't want to buy this car and immediately have to haul to the transmission.


Thanks very much.



Chris
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Postby Doive » 04 Sep 2006, 08:23

I've seen this kind of problem before on BMWs. It's usually nothing more serious than low fluid level, but pull the dipstick, check the level and also have a good look at the colour of the fluid. If it's red, it's good. If it's brown or worse black, have another think about the car. Have a sniff of the fluid as well, if it smells burnt then the box is in the process of eating itself. Usually such problems go away with a fluid and filter change, but it's up to you if you want to buy the car. All the best!
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Postby UpNorth » 04 Sep 2006, 11:01

If the box has the correct fluid level in it don't buy it. Gearboxes don't stop working just because of a 4 month rest.

If the buyer reckons it just needs a few jobs - let him do it & prove it to you :wink:
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Postby ricky b » 04 Sep 2006, 13:07

If the box won't change up into 3rd(presumably top)gear the governer is probably shot.New box or expensive strip and repair i'm afraid :(
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Postby cboyne » 04 Sep 2006, 15:30

Can you guys help me out with locating the tranny fluid dip stick. I never thought to check the levels. I am probably going back out to have a look at the car tomorrow so I will check then.

Thanks for the replies.
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Postby ricky b » 04 Sep 2006, 15:58

Hmm..Don't know too much about Pontiac Acadians,however the transmission dipstick can usually be found to the left or right of the back of the engine near the bulkhead.
Most boxes are checked with the oil warm and the box in Drive..park brake on,wheels chocked to stop it running over you!
However you would be best to check a maintenance manual for the correct procedure.
Hope this helps :)
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Postby Herbie_Flowers » 06 Sep 2006, 09:55

ricky b wrote:the box in Drive..park brake on,wheels chocked to stop it running over you!

don't think so mate :shock:
the dipstick markings will determine how you check the oil level. the normal way is to warm the transmission/car thoroughly, select Park or Neutral with the engine idling and handbrake on and then read off the level on the dipstick. the other way to do it is exactly the same except with the transmission/car cold and check the oil level against the cold markings on the dipstick (if they're there though). parking on the flat is advisable too.
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Postby ricky b » 06 Sep 2006, 13:28

:roll: My apologies,car should indeed be in park with the engine idling.I'm sure one of the autos i've had required the box in drive,but i couldn't tell you which one!! :lol:
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Postby CancerWagon » 08 Sep 2006, 02:56

Is this is halifax NS? I would be able to either give you a hand with this beast or buy it if you don't. Assumiung you're looking at a North american with a 3 speed THM 180 automatic:

The autos (when at full throttle) will stay in 1st gear untill 70kph, with the 2-3 shift at 100kph. The following can cause this to happen when you are not at full throttle accelleration. (you'll need to haul off the air cleaner)

1: check the vaccume line going from the intake manifold to the transmission, if there is no vaccume signal to the tranny it will assume hard accellerating conditions and remain in lower gears longer. This is a steel line that connects to the back of the transmission from the intake.

Testing: Disconnect this line at the manifild end, and find a way to "suck" on the top end without pulling the transmission fitting loose, if you can't sustain a vaccume in that line than there is a break or it's come off. Two short bits of rubber hose and a lengh of 3/8" steel line ($20) will fix this problem. This line is prone to being rusted out and leaking in some climates (nova scotia *cough*)

2: The "detent cable" that goes from the carbruator (the same place as the acclerator pedal cable does) This detent cable is what tells the transmission to shift at 70 & 100 durring full throttle, and if it sticks in the pulled position (it only moves about 1cm, at full throttle only) this will prevent a 3rd gear upshift below 100kph.

Testing: disconnect it from the throttle, and pull on it, if it moves about one Centimeter and then retracts freely the same distance when you let go, it's fine. If not, this is your problem. It's really annoying to remove it from the transmission end, but taking it completely off, freeing it up and getting plenty of libricant in there will generally save you replacing this cable.

Best if luck. And let me know if you don't buy this car, and it's in NS.
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