3 bolt to 4 bolt gears swap

[negroturbo]

Hi guys. I am new at this but here we go. Does anybody knows if it is possible to use the gears from an automatic LSD 3 bolt rear inside a 4 bolt 5 speed LSD unit. The only swap into the 4 bolt unit will be the gears out of the 3 bolt auto LSD. Thanks in advance.

 

[GRNDSM]

You can't do it, because automatics have different rear end ratios.

Leon
RR

 

[negroturbo]

I know that automatics have a different gear ratio and that is why I want to swap the ring and pinion from the auto 3 bolt into the 5 speed 4 bolt. My question is: Will the ring and pinion from the 3 bolt auto LSD fit inside the housing and LSD unit of the 4 bolt 5 speed?

 

[MustGoFaster020]

Chances are they will, manufactures are lazy and if one needed to be bigger than the other to fit they most likely made them all bigger (the casing). That said there is a good chance that you will screw up your tranny if you don’t change the front ratio too. You would have a speed differential from front to back, which is ok if it were not too big or continuos. It would be similar to towing the car with only the front wheels off the ground.

 

[negroturbo]

Thanks MustGo Faster, It sounds logical that the manufacturer would not use different housings just to avoid increasing the cost of production of the car. I know about the ratios when it comes to AWD and in my case I just wanted to know if the swap could be possible just because my car is AWD an auto and I could not find a 4 bolt auto rear end. Meanwhile there are a lot of 4 bolt for 5 speed cars for sale, so since the gears on my 3 bolt LSD unit are perfect I was going to buy a 4bolt for a 5 speed and change the gears for the ones in my 3 bolt rear to keep things as it should be. Thanks again for your responses. And BTW the gears are interchangeable.