412 automatic differential needed

[Mike 2092]

I'm looking for a differential for my 1973 412 (mine blew up). I'll buy an entire transaxle or parts or ??
Any help is appreciated.

Email me at: ecrover@midcoast.com

Thanks,
Mike

[raygreenwood]

Define blew up. Those are quite bulletproof. Usually, they only break from transfer of fluid from the other case section. Meaning transmission fluid moving from the automatic section and mixing with the gear oil. In that case...the entire tranny is junk. I have said this 100 times or more.....if you have a type 3 or 4 auto...and YOU personally have not changed the seals....it must be done NOW...TODAY....chances are it may be too late.

By the way...you should be able to use a type 3 differential assemby. It should bolt right in. But make sure it is the late model auto...no the early style. Look in the rown type 3 bentley manual for help in identification of these two. Ray

[412le]

Hello

Be aware that the type 3 autotrans use another gear ratio than the type 4 in the final drive.
Only 411 from the first 11 month of production (69) use the same final ratio as the type 3

Best regards

Frank

[raygreenwood]

Thats not really a factor. The type 3 differential carrier is the same. Thats all that matters. The entire differential carrier, ring and pinion assembly...simply bolts right into the bell housing assembly. The gear ratios available were I believe, 3.73:1, 3.90:1 and 3.91:1. Some of the type 3's may also have had a 3.67:1.
The 3.90:1 is the most common. Its found in most of the type 4 varients. In a variant.....you would be tasked severely to tell the difference between the 3.73 and the 3.90.....in an automatic. In the 4 speed...there is a big difference.

Either way....they bolt right up. Just be sure of which side axle flanges you use. the early type 3 will not bolt into the type 4. Thats not saying that the differential could not be used...just a few adjustments mst be made. Ray