Rear Diff Fluid

[Mcard23]

So is anyone changing their 5BW's diff fluid both before AND after their first track day? My gut feeling is that one or the other is necessary--what does the ZL1 manual say to do?

I did both before and after my first track day. Same procedure as my camaro

 

[Head Hunter]

Looks like it to me lol. Very different looking unit than my 6gen

I wonder if they changed the plugs from 22 to 23 - mine was a 1/2 Hex Bit Socket

 

[minn19]

Just did my diff fluid today. I‘ve used Red Line oil in my ZL1s (and other vehicles) with no issues so I used that in the 4V BW. Also used their oil as I did that at the same time. Thanks to a previous poster, I got a T70 for the drain/fill plugs and they were correct for the 23s anyway. Didn’t know the torque value so used 50 newton meters from a post in this thread. Sounded pretty close to what I used on the ZL1 IIRC.

I was surprised to see that it was much cleaner than my ZL1 diffs oil. Not even close to the same amount of gunk on the drain plug.

Break in miles and fluid changes done, time to have fun!

Links for those interested in a different oil option.

Euro-Series 5W30 Motor Oil

Euro-Series 5W30 Motor Oil

www.redlineoil.com

75W85 GL-5 Gear Oil

Popular in many late model BMW, Dodge, Ford, GM, Jeep, Lexus, Mercedes-Benz, Ram, Toyota

www.redlineoil.com

 

[Mcard23]

I wonder if they changed the plugs from 22 to 23 - mine was a 1/2 Hex Bit Socket

That's bizarre, but I guess nothing surprises me anymore lol

I was surprised to see that it was much cleaner than my ZL1 diffs oil. Not even close to the same amount of gunk on the drain plug.

Same here, my 1LE's plug was always filthy.

 

[minn19]

That's bizarre, but I guess nothing surprises me anymore lol


Same here, my 1LE's plug was always filthy.

I wonder if it was a supply chain issue? Maybe for some reason they couldn’t get the other drain plugs anymore. Who knows nowadays, it seems bizarre is the new normal unfortunately.

 

[MookdocOE]

Rear Diff done today? Anybody know why GM is not using Magnetic drain plug on these?

 

[DCV]

I suppose you could use some strainer material to pour the used oil through to see if ya got any sparkles in there.

 

[rubberduck]

I just run a magnet through the oil.

 

[MookdocOE]

I suppose you could use some strainer material to pour the used oil through to see if ya got any sparkles in there.

I suppose I could? Most OEM Diffs I have take off have Magnetic drain plugs? Anybody know WHY CTV BW don't?

 

[Deneed4spd]

Anyone know if there is a crush washer on the diff bolts that I have to replace?

 

[rubberduck]

Anyone know if there is a crush washer on the diff bolts that I have to replace?

These are threaded plugs, not bolts and so no crush washer.

 

[Deneed4spd]

Just did my 5BW diff flush. Got the fluid from my local dealer which services approx 1 5BW per month so they gave me the fluid that match the picture listed on this thread. Stuff isn’t cheap! I got my car jacked up using quickjack. Took a while to figure it out. I have a 6000 series that was short 2 inches lifting the car perpendicular. Such then I had to add onto my 7000 series extender that I use to lift my bmw x5 perpendicular. Yes, you can use your quickjack this way and is confirmed by the company. They even have a video on it. I used the smaller rubber block with the quickjack and you can see the jack almost touched the catbacks. Need to see how to use the taller blocks next time. The oil filter and bolt can be accessed even with the quickjack for oil changes which is good.

Anyhow, got a T70 and barely fit the gap to open up the two plugs with my socket set. I’m at 1639 and the fluid had a shiny metallic hue to it when it drained. Even though I haven’t tracked it yet, and kept it pretty mild to 1500 miles, the fluid was not clear. I did the diff in my Honda truck with 7000 miles on it and I could see that fluid was clear. This was not. Glad I did it early even without tracking.

Here are some pics

 

[thefleshrocket]

Just did my 5BW diff flush. Got the fluid from my local dealer which services approx 1 5BW per month so they gave me the fluid that match the picture listed on this thread. Stuff isn’t cheap! I got my car jacked up using quickjack. Took a while to figure it out. I have a 6000 series that was short 2 inches lifting the car perpendicular. Such then I had to add onto my 7000 series extender that I use to lift my bmw x5 perpendicular. Yes, you can use your quickjack this way and is confirmed by the company. They even have a video on it. I used the smaller rubber block with the quickjack and you can see the jack almost touched the catbacks. Need to see how to use the taller blocks next time. The oil filter and bolt can be accessed even with the quickjack for oil changes which is good.

Would you mind sharing a couple pics of your Quickjack with the extenders attached?

 

[techdude99]

Looks to be basically the same as the Camaro... always dirty regardless of how I drove it.

For those that care, Magnetic drain plugs are easy to find for these drivetrains.

I gave up on the Quick Jack's because they weren't quick.... switched to Esco jack stands and haven't looked back. I'll be adding a two post lift in the new garage.

 

[Metal4all6]

I changed my 4BW rear diff oil out tonight at just over 3k miles. I did it without jacking up the car (and I'm a big fat guy). Just needed to scoot under the back as far as i could go and stretch out my arm + use a 6in extension. Mine took about 1.5 quarts before it started dripping from the fill hole.

Anyone know the torque specs on the fill and drain plugs? I snugged them up with a ratchet, but would prefer to have them torqued to spec.

 

[Mircrowaved_Bananas]

Anyone know the torque specs on the fill and drain plugs? I snugged them up with a ratchet, but would prefer to have them torqued to spec.

On the 4BW, 37 lb. ft. for both, per the service manual.

 

[jbawden]

I did mine around 1,600 miles and it was clean, maybe slightly opaque but about as expected for so few miles. There is no crush washer and it's not pipe thread, rather it's a plug with a small oring machined into the sealing face.

@minn19 Does the ZL1 diff use the same fluid as the BW? I thought the BW fluid was different. For as frequently as I'll change it (not very often) I'm not going to risk damage and stick with OEM.

 

[minn19]

I did mine around 1,600 miles and it was clean, maybe slightly opaque but about as expected for so few miles. There is no crush washer and it's not pipe thread, rather it's a plug with a small oring machined into the sealing face.

@minn19 Does the ZL1 diff use the same fluid as the BW? I thought the BW fluid was different. For as frequently as I'll change it (not very often) I'm not going to risk damage and stick with OEM.

Its different weight for the 4V BW, might be the same for the 5V BW since it’s the same engine as the ZL1. Torque specs for the fill/drain plugs are the same.

 

[minn19]

Interesting, just checked Redline‘s website (the oil I use) and they recommend 75W85 GL-5 for both 4 and 5V BWs. But, they recommend 75W90 GL-5 for ZL1s.

 

[jbawden]

Not so much worried about the weight but the additive package difference. The Delco fluid is stupid expensive and while I'm cynical, I'm not ready to accept that GM is just bending us over because we bought BW's, there has to be something different.