Rear Differential Oil Fill Concerns

[The Critic]

This past Thurs, I did a rear differential oil drain and refill on a '92 Toyota Previa.

I had the oil on hand, but wasn't exactly "planning" to do it. (I didn't think I'd have time) So, I drained the oil after I was done with other work, so the oil was relatively cool after three hours of sitting.

The manual says 1.6 qt for refill. I put in 1.25 RP 75W90 and it was already dripping out of the fill hole. I filled the differential while the van was on a lift, but the rear end might have been about 2 inches higher (at most) than the front.

Should I be concerned about the fluid level? I had the instructor (who is a professional mechanic) check it and he said the level is correct, but I'm worried that it may be under filled?

Thanks.

 

[Eddie]

I see no problem if the rear of the vehicle was only 2 or 3 inches higher than the fron of the vehicle.

 

[Titan]

The instructor is correct. If the rear was higher, you could have a few tablespoons MORE than is required to be called "full", but, it is an insignificant amount. Some people do it that way on purpose, so they can get just a bit more in there. Don't worry about whether the manual says 1.6 for a refill. You don't fill it more than up to the bottom of the filler hole. My guess is you didn't get all of the old oil out, but it is not underfilled.

 

[alanu]

absolutely fine

 

[Shannow]

I've never seen a differential take the recommended amount of oil.

It will be fine.

 

[cousincletus]

Oil level is full if you can see oil on the tip of your finger when you stick it in the hole. Chrysler recommends the oil level being below the fill hole. Better to underfill a little than to overfill for sure. That could make the oil foam easier.

 

[The Critic]

Yeah, when I stick my finger in there, it's right to the neck of the hole.

Thanks guys...

PS: I can run this for 50k right? Royal Purple Synthetic 75W90. This van is highway driven.

 

[cousincletus]

I use Amsoil 75W-90 (the blue stuff I think is called Series 2000) and plan to change it every 60K. From my understanding you can at least double the service interval by using synthetic. Most people just leave it in for life after making the switch.