Transfer case fluid question

[Msondeck]

I waited too long to change fluids for transfer case as it began making sounds under acceleration.
I recently had it changed at 55k miles yet sound is still there.
My mechanic suggested trying a thicker fluid before replacing TC but doesnt want to order it incase anything goes wrong.
Anyone here know of a thicker oil that would work? Or if a thicker oil will work?

[///MCollection]

I wouldn’t use any thicker oil, are your tyres in spec and were the adaptions reset/transfer case recalibrated as this needs to be done

[Msondeck]

Originally Posted by ///MCollection

I wouldn’t use any thicker oil, are your tyres in spec and were the adaptions reset/transfer case recalibrated as this needs to be done

He said it was reset, car didnt feel jumpy or like gear changes were harsh. Just a whining sound under load before and after oil change.
As for the tires, i have not tried the string method but was assured they are within the limits. Ive had the wheels since 10k miles for 8-9 months of each year. Specs are; front 295/30 rear 335/25.
I have to replace front axles and drive shaft so maybe they could be plaing a role here?

[pachieh]

When did you have the diff fluids changed?

[Msondeck]

Originally Posted by pachieh

When did you have the diff fluids changed?

55k miles

[Yuille36]

I would take your vehicle to another shop and physically watch them recalibrate your transfer case. I would also ensure that there was enough fluid added to the TC, as do don't want to ever run low of fluid in the TC, and same goes for the front and rear diff's.

[tfunk88]

I bought my X5 at 93k miles. Transfer case fluid had never been changed before. I changed the fluid and recalibrated the transfer case and it was like new.

The tire sizes you listed, 295/30 and 335/25 (you don’t mention wheel diameter, I assume 22”?) have a pretty decent sidewall height difference, which means a diameter difference outside of the acceptable range. If it’s actually your transfer case I’d guess that difference did some damage to it.

But if you know your front driveshaft and axles are bad is it not possible the sound you’re referring to is coming from them? 🤷‍♂️