I came across a (I believe) 6.5" rear diff about 10 years ago. According to the tag it was a 3.62:1. It looked very much like a 7", but it was very slightly smaller. Also the drive shafts of the 7" diff didn't fit into the 6.5" one.


Here are some pics of the 6.5" and 7" next to each other. The darker one is the 7". Unfortunately I don't have it anymore. I gave it back to the guy selling it to me as it didn't fit my car. From what I can make out of the tag on the diff it said: 83BG4006CD **5F4N3.62.














Here is some info on what diffs were fitted to which cars.

 

Marc. You always come up with really good information on anything that is puzzling people about their car. Good on you.

 

Thanks!


If I come across something interesting on the internet I most of the time save it, so over the years I got quite some documents on Sierra's, Cosworth and related things.

 

I pumped to this old thread when I tried to find out about Sierra 1.3 OHC diff ratios. I have quit early 1.3 5 door Sierra GL (with turbo installed when new) and I'm quit shure finish user manual listed it as having 4.xx diff. It is in quit hard place to reatch now so I report back when snow melts if somebody is still interested. I have many Sierras and parts so I have looked at it and drive safts and shell are smaller than 7". Turbo Sierra has now 7" ZF diff and whole axle but I saved the old one.

Vin plate said axle B so it's 3.77 but there are letters and numbers for over 4.xx ratios and I'm still sure that I have seen ratios over 4 marked for 1.3 OHC.