Rear End, Differential Questions and Answers! We ship worldwide!

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Automotive Parts Warehouse and Installation Repair Center ring and pinion setserving Metropolitan Minneapolis MN area..

Question 1) Ratio Change

Question 2) My rear end is leaking fluid from the front of the differential housing?

Answer 1) Why should I change the rear end ratio in my vehicle?

Reasons to change your rear end ratio

  • You installed large tires to get lift, you will need lower ratio probably 4.10 or lower possibly 4.56.
  • Your vehicle came from the factory with 4.10 ratio you don't tow any heavy load and get poor fuel economy. You need higher gear ratio say 3.73 or possibly even 3.42
  • Your vehicle came from the factory with 3.42 ratio and you need to tow larger loads, then you will want to install 4.10 ratio
  • You use your trunk for farm work or off-roading all the time you will want 4.10 ratio or lower for more power.

Answer 2) Pinion Seal Leakingleaking pinion seal

The fluid is leaking past the pinion seal, this is typically caused by pressure build up in the differential housing when the vent is plugged. This can also be caused by excess fluid level in the housing, i.e. water getting in. Say you are driving the vehicle and you get into water flooding or backing into a boat dock, the differential is hot, goes in the water and cools causing water to be drawn in to the housing (this can and will also damage rear end bearings. A third cause of pinion seal leak is called grocery bag failure. You are driving down the street and run over an empty plastic bag, the bag is picked up by the spinning driveshaft, wraps itself around the rear driveline ujoint and melts causing heat build up damaging the seal.

We found a very good video on you tube that explains in detail how to change the pinion seal. Note that the mechanic is very careful to mark the location of the flange, we suggest that before you remove the driveshaft you also mark it so that it can be returned to the exact place. The video is below, let us know if you need parts we can help.