I would like to know what some of you have done to bolt up a manual drive shaft on to the stock auto 3.90 rear end after an auto to manual swap.I was thinking of drilling new holes in the rear end plate but not sure if its a good idea.

 

I swapped the companion flange out with one from a manual differential. Everything bolts right up.

 

where do i get one of those companion flanges?

 

P04527120B at the dealer for about $170.

Or here on the forum from someone who has a junk 5 speed differential for about $50.

 

get it for a bit cheaper if u call Ray Crowe at Malloy Mazda. He overnights it for ten bucks. I have been to broke to get a companion flange so i widened the holes on the my auto companion flange and it works just fine.

 

Drill new holes. Done. The driveshaft can't get off center because of the small flange in the middle that holds it in place.

 

Yes, I've done a auto to manual 5 speed conversion about 6 months ago. I'm a little puzzled on why you are keeping the auto differential with 3.90 gearing for a 5 speed manual transmission that is engineered for the 4.11 standard differential?

It will limit the top end potential, being of lower ratio, unless you plan to drag race your machine?

 

I am aware of that i just don't have a 4.11 at the moment. I will get one soon but in the mean time i want to get the car running,