: 89 fleetwood rear differential blown or pinion seal?



tex210
08-06-13, 01:43 AM
posting this for a buddy..hes got a 89 Cadillac Fleetwood brougham rwd. not sure what size motor but its not the 4100. well he had a bad vibration/howl noise from rear axle and had some play in the driveshaft when u would move it up and down by hand. he ignored it and it finally left him stranded today. The car wont go anywhere in drive or reverse and u can see the driveshaft spinning but the car wont go. so when I go to put it back in park it makes this whining down noise like gears clicking together to make the driveshaft stop spinning. Also when I went to go tow him home he had differential fluid all leaked out on the floor from the rear on the yoke side. it looked pretty black in color. I was gonna swap out the whole rear end but questioned myself if I change just the pinion seal and add some fresh fluid should it be good to go. if not what other cars are interchangeable for the rear ends?? thanks in advance

cadillac kevin
08-06-13, 10:18 AM
You can use a rear end from any 7.5 inched rear end b or c body. So lesabre, electra, 88, 98, parisienne/catalina, bonneville, caprice, fleetwood/deville/brougham.

csbuckn
08-06-13, 10:53 AM
It would be easier to repair the unit if repairable but it's more then a pinion seal. Probably gonna need a ring and pinion and the tools to set it up right. Hopefully that's all you need.

The Ape Man
08-06-13, 06:38 PM
The diffy is done. Replace the whole drum to drum. Probably want the same gear ratio. Axle codes are on the axle tube. Peeps here can tell you exactly where.

tex210
08-08-13, 05:29 PM
after getting it up on some stands it turns out the bolt that holds the rear yoke in place came off causeing the yoke to pop out and leaked all the fluid out and ruined the splines and thread. I picked up a complete rear end used out of a 86 chevy caprice for 110$. does any one know if this will work???..i noticed they both measure the same length and have the letter B stamped on both of them.

The Ape Man
08-08-13, 10:08 PM
The Chevy may use4 different bolt circle on the rims IIRC. The axle flange may be a different style or have different saddle width for U joints. Drums are usually cheesier 9" on chevrolet as opposed to 11 on Cad. Also check bushing thickness. Chevy can be smaller but made to work.

I once stuffed a 1984 Chevy full size posi underneath my 1977 CDV and made it work so it can be done.

cadillac kevin
08-08-13, 10:35 PM
after getting it up on some stands it turns out the bolt that holds the rear yoke in place came off causeing the yoke to pop out and leaked all the fluid out and ruined the splines and thread. I picked up a complete rear end used out of a 86 chevy caprice for 110$. does any one know if this will work???..i noticed they both measure the same length and have the letter B stamped on both of them.

If it is out of a sedan, you will need 2 4.75x5 rims for the back....or swap the axle shafts so you can keep the 5x5 rims. If it is a wagon, it's 5x5 bolt pattern and will be fine as is.

tex210
08-10-13, 03:22 AM
thanks for all the info especially Cadillac kevin who put me on the right track. I bolted up the caprice rear end and swaped over the axle and brakes from the caddy rear end to the caprice rearend. all worked out well and thanks again to all for all the info. great forum