Front differential fill level

WarGawd

Well-Known Member
#1
I just posted an alternate solution to the really difficult to remove front diff fill plug problem, but had a related question.

In the process of R&Ring my steering rack, I used this opportunity to (finally) drain and refill my front diff. However, when I found it difficult to reconnect the power steering pressure hoses at the steering gear, I chose to go the route of removing the CV axle to give me the room I needed.

You guessed it - when I removed the CV, I lost a bunch of my new front diff fluid.

I know the fill level is supposed to be the bottom of the fill plug hole, but since I was never able to get the fill plug out I had to resort to the above mentioned alternate solution.

And now that leaves me uncertain how close to the proper level I actually am now.

So the question is: relative to the bottom of the fill plug hole, how much lower is the bottom of the CV axle opening? I'd say I lost 1/3 - 1/2 quart with the CV out - might there still be an adequate amount left in the diff (I'm almost certain there is at least twice as much new fluid remaining even now, as the old crappy stuff that I drained out when I changed it a few days ago)

Any other thoughts?
 
#2
I just did the same late last night ,well the part about removing the driver side CV shaft... I ve been chasing a vibration and also a clicking, knock, bang issue thats driving me nuts. ordered new cv shafts and hubs to see if that will fix it.

when I removed the shaft I'm thinking I may of lost more closer to a full quart of fresh fluid. I'm mad at myself for forgetting to put a clean pan under the diff so I can just reuse the fluid.
Anyway my truck was lifted on the driver side and like I said I lost closer to a full quart so are you even sure you had the right amount of fluid in there???
My wife will be driving the truck for the next few days as is or until I get the parts I ordered then I fill the front diff back up with fresh fluid yet again. lol
 
#3
Looking at this picture of the diff:



We can see that the bottom of the fill plug is about halfway up the axle hole. You could try topping it up through the axle hole with the driver side jacked up as high as possible to add an angle but probably won't get it as high as it should be. Better than what you had before for sure.
 

Reprise

Lifetime VIP Supporter
#4
One has to wonder why they allowed the supplier to use that design for the fill plug. It couldn't have been due to restricted access -- I remember having a straight shot to it through the wheel well last summer -- and not being able to budge it with my electric impact. The traditional 'inset plug' works well, doesn't take up a ton of space, and is used almost universally across automakers--hell, even my Hondas use it. But not this differential.

Decided to leave well enough alone, as I use the front diff maybe 4 occasions a year, and only two of those for actually driving in a 4wd range. At this point, maybe I should just give the next owner something to do...lol.

Actually, looking up the company on Google as I write this, I see now why the plug is the way it is. 'New Process Gear' was a Chrysler-controlled / subsidiary company, originally. 'New Venture Gear' was a renaming of the joint entity created by Chrysler & GM - the first of its type between any of the US Automakers (don't know how true *that* is, personally).

Chrysler provided the product design, through their company; GM provided the Muncie (former) transmission plant as a manufacturing / assembly site.

Here's the story: https://en.wikipedia.org/wiki/New_Venture_Gear

So our 360s have some Chrysler blood in them.
At least it's not the transmission...lol.
 
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WarGawd

WarGawd

Well-Known Member
#5
Anyway my truck was lifted on the driver side and like I said I lost closer to a full quart so are you even sure you had the right amount of fluid in there???
Excellent question but I was pretty sure I had very close to the spec'd amount in there. I had bought 2 x 946ml (1 US qt) bottles, and used my fluid pump to put in 1450ml (1.53 US qt). I have 500ml left in one bottle. I'd say I lost less than an ounce (~30ml) when I removed the brake line from the drain hole and replaced it with the drain plug. This should have left almost exactly 1.5 US qt in the differential, using @MAY03LT video as my capacity reference.

Looking at this picture of the diff:
We can see that the bottom of the fill plug is about halfway up the axle hole. You could try topping it up through the axle hole with the driver side jacked up as high as possible to add an angle but probably won't get it as high as it should be. Better than what you had before for sure.
Thanx Mooseman...that picture gave me a pretty good sense of it. I may drain and capture the fluid and refill it, or, as suggested by Roadie on the OS, just add it thru the vent tube (another clever solution that never occurred to me).
 
#6
I hate the 3/8" square drive inset plugs, personally. extensions all have rounded corners and such, so they tend to round over (or round out) the relatively shallow hole. I've had a lot more trouble with those than a bolt head plug. That said, the fill hole IS pretty huge, so I'm sure that extra diameter of threads that could get stuck doesn't help.

My Silverado has the same style fill plug, by the way. Have had no problems getting the fill off of either the Trailblazer or the Silverado with just a socket and longer ratchet.
 

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