'85 Mazda RX7 gearing troubles
I built an ’85 Mazda RX7 with a 351 Windsor from a Lincoln and a world class T5. It still has the original rear end. When I put in the world class T5, I also decided to change the gearing in the rear end from the stock 4.11 to a 3.909 from a 626.
This was a mistake due to the gearing I chose for the transmission. It has fairly low gears from first to forth and a high fifth. Even with the 3.909, first gear is useless, and I find that the response off the line is not as good as it was with the 4.11d.
So, to skip ahead, I decided at great length to put the damn original 4.11 gears in. I was under the impression that they were interchangeable except for the limited slip carriage, so I was prepared to go for it.
I was wrong.
The 4.11 was not ready for a simple swap. All of the bearings were shot. I had to replace them or go back to the 3.909, but that was not a good option either because all of the bearings in it are also shot (I thought they were new when I paid to have it built).
These bearings are rare. Mazda is no longer supporting this rear end, so I had to go to a bearing shop to try to find them, Motion Industries. They were happy to help. They found all the bearings and the seal (but the spacers and sleeve are not to be found). Stay tuned for the results.
A while ago, I helped a friend to regear a Land Cruiser. So I have some experience. I understand that setting up the pinion with the right preload is the hard part.
This was a mistake due to the gearing I chose for the transmission. It has fairly low gears from first to forth and a high fifth. Even with the 3.909, first gear is useless, and I find that the response off the line is not as good as it was with the 4.11d.
So, to skip ahead, I decided at great length to put the damn original 4.11 gears in. I was under the impression that they were interchangeable except for the limited slip carriage, so I was prepared to go for it.
I was wrong.
The 4.11 was not ready for a simple swap. All of the bearings were shot. I had to replace them or go back to the 3.909, but that was not a good option either because all of the bearings in it are also shot (I thought they were new when I paid to have it built).
These bearings are rare. Mazda is no longer supporting this rear end, so I had to go to a bearing shop to try to find them, Motion Industries. They were happy to help. They found all the bearings and the seal (but the spacers and sleeve are not to be found). Stay tuned for the results.
A while ago, I helped a friend to regear a Land Cruiser. So I have some experience. I understand that setting up the pinion with the right preload is the hard part.
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