trans/diff dumb question

[fletch90]

first time posting on this forum, sorry for just posting instead of reading previous posts /ubbthreads/images/graemlins/cool.gif
my gearbox/differential is from an 89, the 3 bolt 3.545 ratio.
i want to replace the diff with a 4 bolt viscious 3.909 ratio from a 91.
unsure if ratios need to be matching, tbh unsure if the ratio is even relevent to gear box /ubbthreads/images/graemlins/dunno.gif
will just swapping the diff work properly or cause proplems with the gearbox?

thanks for your help!

 

[fuel]

You need to be running a matching gearbox, diff and transfer case combination. You cannot run the 3.909 diff with your existing gearbox/transfer case which is expecting a 3.545 rear diff.

 

[fletch90]

thankyou!

 

[brisvr4]

Just put the LSD centre into your 3 bolt pumpkin and call it a day.
It's not rocket science /ubbthreads/images/graemlins/smile.gif

 

[Olson]

So much bad info in this thread.

No it wont work if you swap everthing over. you need to match your trans to the read diff.
Yes you can swap the rear viscous BUT you will need to take your .... planetary gear the big gear that goes around the diff and put it on the new diff. from there you should check your lash. After doing this you should be good to go. Also the axles that go into the diff are different from non lsd to lsd and what type of lsd you are using.. sh*t to think about.