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robertwheeler

1987 gl Wagon w/turbo 4wd Nuts and Bolts

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As you may have guessed from reading the topic line in this thread I am having problems with using 4wd on this car. I have a couple of Idea's based on past experience with other cars... I would like to understand exactly how this 4wd works so I can properly Diagnose it.

 

First IL explain my problem briefly.

 

I popped it into 4wd today and it was very difficult to get it moving... and after I got it moving.... it quickly dragged to a halt. I managed to get it parked and then it took several Min's to get the 4wd solenoid to disengage... I think it came out after I put the car into reverse...

 

As I understand the way it works.... its not unlike the back part of an older rear wheel drive car.... you have a differential and in the case of this subu a long drive shaft coming from the rear of the trans-axle to the differential. What I'm really not sure of is where the solenoid that causes 4wd to select the other 2 wheels is actually located and functioning... My Guess is it's on the transaxle somewhere. If this is true then the rear differential and the drive shaft will spin when ever the car is in motion.... not be engaged to the trans-axle.... and if this is the case it leads to believe the problem is in the part of the trans-axle that serves as Rear Power take off for the car..... and just maybe if it is separate from what drives the front wheels.... Either lack of fluid (gear oil) or some related problem.

 

Anything at all that would help me understand this functioning would be quite nice :)

 

Thanks

Robert

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You have a front differential and a rear differential, but there is no differential between the front and the rear. That means that the front and rear differential need to turn at the same speed. The most likely cause of your problem is binding due to different tire sizes. Someone may have also replaced your transmission, or possibly rear differential, with one out of a non-turbo model. They have different gear ratios; the turbo is 3.7:1 and the non-turbo 3.9:1.

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You have a front differential and a rear differential, but there is no differential between the front and the rear. That means that the front and rear differential need to turn at the same speed. The most likely cause of your problem is binding due to different tire sizes. Someone may have also replaced your transmission, or possibly rear differential, with one out of a non-turbo model. They have different gear ratios; the turbo is 3.7:1 and the non-turbo 3.9:1.

 

Tire size's... that I will found out about.... As I need 3 of these.

 

My Brother had this car for over 3 years and about 33k miles.... None of these parts where ever changed... and it seemed to work ok for the first 2 years.

 

Thanks

Robert

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I did some follow up reading on this.

 

If I understand correctly most of the car's that we have in this forum.... older generation are part time 4wd. And by design or lack there of.... 4wd on dry pavement isn't a great idea.... Since the wheel's theoreticly start at the same speed... but this changes dynamically as you turn.... or even just driving.

 

I suspect that my binding problem will be less of an issue in the snow... as the snow would allow the wheels to equalize a bit more.... But I definitely need to get some decent rubber on this Subaru..... not all the 4wd in the world is going to help me with these tires.

 

Robert

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