2001 V70XC 117k miles
Saw some wetness on the bottom of the Viscous Coupling (VC) which is likely due to a leaky real differential pinion seal. Resource section contain Volvo's directions. Here are some addition notes and how to get around those custom Volvo tools.
First, here is the direction in the resource section
Here are some key notes
- Have to pull the propeller shaft of course. I was able to pull the prop shaft out without removing the exhaust. Directions here
- When I turned the bolt for parking brake mount. It snapped the plastic mount. Picture below shows the metal bolt and the metal sleeve that threads into the underbody was rusted together and therefore impossible to remove it without breaking the mount. This mount is likely unnecessary as the parking brake cable has plenty of other mounts/clips holding it in place. But I'll probably hunt for plastic replacements at the local hardware store. The cable also need to pop out of the clip on the tunnel near the VC, that plastic clip also but remains usable
- No need for a mobile jack. When dropping the rear differential (need to do this to have enough room to put a socket on the top bolt on the VC that bolts it to the rear diff), just loosen the bolt that drops the rear diff but don't take it all the way off.
- Getting to the top bolt on the VC requires 2 long extensions with a universal in between
- Rear exhaust pipes has 2 rubber mounts just behind the rear differential that holds it up. Pull the rubber mounts off the underbody hooks allows the exhaust to drop a little. Just enough to remove the VC.
- No need for Volvo's fancy seal puller to get the old seal out. I just used a pry bar and used the pinion shaft as leverage. The seal is made of thin metal with rubber molded onto it. The pry bar will definitely distort the seal but it comes out pretty easily. The metal on the seal is pretty thin. I'm guessing Volvo's seal puller might distort it a bit as well.
- No need for Volvo's fancy drift to put the new seal back in. 1-1/2 inch pipe cap ($5) was a perfect fit for the seal and seats it perfectly at the right depth.
The cap is a tad bigger (3/32?) than the diameter of the seal. I thought about grinding that extra area with a bevel so it would make a perfect fits over the bevel on where the seal goes on the rear diff. But I give it a try as is and it went it perfectly. Of course it went it at a slight angle as often happens on these seals (1/16 higher on one side than the other), but I just tapped it in on the raised side and it went in all flush
Here is the picture of the pinion shaft with the seal removed. Its hard to see in the picture but there is a beveled lip where the seal goes. The seal basically has to be seated at the inner edge of the bevel (from looking at the original seal)
When I used my Mityvac to put in the new gear oil. The filler hole started leaking at 500mL. I guess there were still oil below the pinion shaft opening. 01-02 real differential calls for 700mL and 03+ calls for 500mL according to VIDA.
- Rear Differential Pinion Seal Ring PN 1385077-1. $25+$8 shipping from Darrel Waltrip Volvo.
- 1 quart Mobil 1 75W-90 synthetic gear oil ($12 local auto store)
No leak after a quick test drive. Will keep an eye on it Now onto that pinging front CV on the propeller shaft (since I have it out). The front CV fails often because the rubber boot gets cooked by the hot CAT nearby.