Did I overfill 8.25" front diff w/ my frankenbrew?

[Islandvic]

Vehicle in question is 2005 Suburban Z-71 w/ 8.25" front diff & 103k miles.

I changed the rear diff fluid at around 88k miles but was bad and didnt change front diff fluid until now (at 103k miles).

Front diff had original fill.

I noticed the right axle seal had a leak. Didnt see fresh leaking fluid, but signs of grime build-up where the cv shaft slung it around.

From what I have seen on the Amsoil website, the front diff hold 3 pints (48oz).

When I drained the diff, only 40 oz drained out. So I lost 8oz over 103k miles.

Being cheap, I cleaned the right side seal area real well and didnt fix it.

I instead filled the diff first with 32oz of Castrol 75w-90 sythetic gear oil then 16oz of Lucas Synthetic Oil stabilizer. the Lucas bottle says I can mix up to 50/50 in diffs.

The 3 pints I installed didnt raise the fluid level to the fill hole, so I added 10oz of amsoil 75w-90 until the level raised to the fill hole.

I now have 58oz of fluid in the diff that spec's 48oz.

My question, will the 10oz extra be harmful to the diff?

I used the Lucas to see if it wouild stop the seal leak. I cleaned the axle and seal area so I could detect if it leaks still.

Also, where is the other end of the vent hose on the front diff, and how do I make sure it is working properly?

thanks for your input

 

[SwampSurvivor]

It can cause it to foam (which would be bad). The Lucas oil stabilizer is just a heavy, detergentless oil ... essentially, you paid for detergentless gear oil.

With that said, my Cherokee's Dana 30 has a bad pinion bearing and it leaks. I park it on a steep hill and overfill (not sure by how much). Doesn't make it any worse (or better).

 

[Bottom_Feeder]

Originally Posted By: Islandvic
I used the Lucas to see if it wouild stop the seal leak.

Why would it? That's not what the product is designed for.

 

[Doog]

Originally Posted By: Islandvic


I noticed the right axle seal had a leak. Didnt see fresh leaking fluid, but signs of grime build-up where the cv shaft slung it around.



Common problem on GM trucks for many years. I had 2 of them leak and were found and repaired by my GM dealer for free. You will never fix it with stop leak and eventually lose all of your lube and cause a diff or bearing failure. Best to repair the seal. Then add the correct amount of diff lube. BTW, I would recommend you only use the GM lube speced for that diff and it will go 100k.