Follow up.
Have successfully performed the differential fluid change however, realized the differential fluid capacity is 1qt..42 ounces if not mistaken. I believe I usad 1 quart and a little less than the .42. Awaiting additional bottle to arrive however, wanted o confirm if any issues (if any), may be experienced if less than the 1.42 oz is used. If so, what might it be (clicking,heard, impacting launching from a dead stop etc.)?

FOR OTHERS WHO MAY BE USING THE RED LINE QUART BOTTLE;
Have successfully used Plews 55001 Lubrimatic Fluid Quart Pump (PHOTO 1) to dispense the fluid from the Red Line quart bottle.Even though unable to secure the fluid pump cap to the RedLine 1 qt bottle threaded opening (RedLine bottle opening was a smaller diameter than the standard quart size fluid pump cap), the fluid pump sat securely in the RedLine bottle while the fluid was dispensed into the differential, rather quickly. I did us the "third hand butterfly adapter", from the LOZAGU fluid pump (PHOTO 2) to assist with having the clear tube securely stay in the differential fill hole while dispensing the fluid.

PHOTO 1

Amazon

Amazon

PHOTO 2

https://www.amazon.com/LOZAGU-2-Pack-Fluid-Standard-Bottles/dp/B0CKLS7HG3/ref=sr_1_1?crid=20R0BC1C198T6&keywords=Attwood%2Bfluid%2BPump%2Bfor%2B1qt%2Bbottle&qid=1710066330&s=automotive&sprefix=attwood%2Bfluid%2Bpump%2Bfor%2B1qt%2Bbottle%2Cautomotive%2C85&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

https://www.amazon.com/LOZAGU-2-Pack-Fluid-Standard-Bottles/dp/B0CKLS7HG3/ref=sr_1_1?crid=20R0BC1C198T6&keywords=Attwood%2Bfluid%2BPump%2Bfor%2B1qt%2Bbottle&qid=1710066330&s=automotive&sprefix=attwood%2Bfluid%2Bpump%2Bfor%2B1qt%2Bbottle%2Cautomotive%2C85&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

You only bought 1 quart? Plus fluid loss in pump and hoses.
Vehicle needs to be level then fill until it trickles out the fill hole. Running low risks gear and bearing damage. I mean it relies on oil for cooling and lubrication (being slung) up to the pinion bearings.

 

Thank you for the follow up! Fluid change performed on level surface using four ramps. Had purchased 4 qrts., and only used 1 and a half for previous fluid change however, appeared to be less than the .42 in the left over bottle. Will add additional fluid soon, until it begins to trickle out of fill hole.

 

I measured how much I drained and added similar amount of fluid which was 1.58 quarts.

 

I really should have measured what was drained as well however, went by what was specified in the owner's manual;

IS350 / REAR: 1.42 qt. (1.35 L, 1.19 lmp.qt.)
IS250 / REAR: (2WD models): 1.20 qt. (1.15 L, 1.01 lmp.qt.)
IS250 / Rear (AWD models): 1.10 qt. (1.05 L, 0.92 lmp.qt.)

 

I know but I would still recommend you to put around 1.5L. I am pretty sure I drained more than that.

 

Unfortunately, did not keep record of the exact amount of fluid removed / installed. Just filled until fluid began trickling out of fill hole and referenced the amount remaining in the 1 qt. Redline 75W90 bottle.

 

How about doing it from the beginning. Drain and fill?

 

Or fill until it trckles out. No need to measure anything. It's not like you can over fill it easily.

 

I have a stupid question that I cannot find the answer to on the forums. Can anyone please confirm if RWD has a front differential? If so, I have neglected my front differential.

 

Shame on you! Dang! J/K!
Negative captain or it would be AWD.