Low rear differential gear oil volume

[SRZ]

I just drained the rear differential oil tonight (first oil change since factory fill). I first drove the car for about 1/2 hour to warm the fluid and I then let it drain for over one hour until there was absolutely no more oil dripping down. I subsequently measured the drained diff oil in a graduated container and it measured to be just under 1.3 QTs. The manual recommends 1.5 QT fill. My diff is dry without any leaks. Has anyone else noticed that the rear diff fluid appears to be on the low side from the factory?
I also drained the tranny fluid but unfortunately did not measure it.

[Steve M]

1.3 quarts sounds about right to me...that's all I'm usually able to squeeze in to mine. The transmission was probably around 3.4 quarts...keep in mind that if you fill it up to the bottom of the fill hole on the transmission, you'll actually end up filling it with close to 3.8-3.9 quarts, which they don't recommend (probably because it will start puking fluid out the vent if you are driving it hard).

[swexlin]

I just drained the rear differential oil tonight (first oil change since factory fill). I first drove the car for about 1/2 hour to warm the fluid and I then let it drain for over one hour until there was absolutely no more oil dripping down. I subsequently measured the drained diff oil in a graduated container and it measured to be just under 1.3 QTs. The manual recommends 1.5 QT fill. My diff is dry without any leaks. Has anyone else noticed that the rear diff fluid appears to be on the low side from the factory?
I also drained the tranny fluid but unfortunately did not measure it.

When my Viper tech replaced my original diff under warranty, he told me the new unit out of box was low on fluid, and he had to top it off.

[Jprince]

When my Viper tech replaced my original diff under warranty, he told me the new unit out of box was low on fluid, and he had to top it off.

If I were you, I would double check the level. Back when I had my diff replaced, the tech told me the same thing. I later checked the level and it was way over filled.

[swexlin]

If I were you, I would double check the level. Back when I had my diff replaced, the tech told me the same thing. I later checked the level and it was way over filled.

It's going on two years with no issues. I trust my tech.

[SRZ]

Here is an update on my fluid exchange. I drained all the fluids last night and I replaced it with new today.

For the rear diff, I measured 1.5 QTS of Mopar gear oil recommended per manual (I checked my graduated container and it is accurate and my car is on a lift which is very level) to fill the diff. The oil started coming out of the fill hole and I was only able to put in about 1.3 QTS, i.e. same amount that I drained.

Next, I measured 3.4 QTS of Mopar transmission fluid to fill the transmission (per manual). The oil started coming out of the fill hole at about 3.2 QTS.

Next, I filled the engine oil and it required 11 complete QTS with the oil level exactly at the upper hash mark on the dip stick.

Here are the lessons learned from my fluid exchange:

1. When replacing tranny or diff fluid in a Gen V Viper, just put in the new fluid until it starts coming out of the drain hole. There is no need to pre-measure the fresh oil.

2. The manual fluid capacities are over estimated. Rear diff requires about 1.3 QTS (not 1.5 QTS) and tranny requires 3.2 QTS (not 3.4 QTS).

3. Engine requires 11 full QTS

I sent out a sample of engine oil to Blackstone for analysis and will report back.

[kuishe]

1.3 quarts sounds about right to me...that's all I'm usually able to squeeze in to mine. The transmission was probably around 3.4 quarts...keep in mind that if you fill it up to the bottom of the fill hole on the transmission, you'll actually end up filling it with close to 3.8-3.9 quarts, which they don't recommend (probably because it will start puking fluid out the vent if you are driving it hard).

Yo, hopefully you or someone may know of this...

Someone here once posted a pic off the service manual & it says to put the tranny in neutral when doing a flush but never stated why, I wondered since then if this is in fact a crucial step in order to FULLY drain/fill, I imagine if it's in gear maybe some fluid will get trapped in between something? I'm entirely just assuming here so ya...

[Steve M]

Yo, hopefully you or someone may know of this...

Someone here once posted a pic off the service manual & it says to put the tranny in neutral when doing a flush but never stated why, I wondered since then if this is in fact a crucial step in order to FULLY drain/fill, I imagine if it's in gear maybe some fluid will get trapped in between something? I'm entirely just assuming here so ya...

They did indeed: https://driveviper.com/forums/threads/19110-Differential-and-Transmissions-Fill-Procedures?highlight=transmission+fluid

Transmission:
https://image.ibb.co/byD3Ww/Viper_Transmission_Fill_Procedure.jpg

Differential:
https://image.ibb.co/jubCPG/Viper_Differential_Fill_Procedure.jpg

First line in the transmission procedure is to put it in neutral, but I doubt that would have a large impact on fluid capacity. Could be wrong though.

[kuishe]

They did indeed: https://driveviper.com/forums/threads/19110-Differential-and-Transmissions-Fill-Procedures?highlight=transmission+fluid

Transmission:
https://image.ibb.co/byD3Ww/Viper_Transmission_Fill_Procedure.jpg

Differential:
https://image.ibb.co/jubCPG/Viper_Differential_Fill_Procedure.jpg

First line in the transmission procedure is to put it in neutral, but I doubt that would have a large impact on fluid capacity. Could be wrong though.

Well lets hope somebody that knows eventually sees this haha!

[kuishe]

Something silly (or maybe not) suddenly came to mind & thought I share! I wonder if there is any harm to shifting gears with the clutch to the floor but with no tranny fluid while the ignition is off haha...