[Madsen203]

Planning to tackle front/rear differentials, transfer case, engine oil/filter, and spark plugs on 40i next weekend.

While car only have 24k miles on it, I figured the fluid enhange should be quick, easy, and a good preventative given how many posts I’ve seen about these big items shitting the bed early on the X7 - especially being they only hold 6-800ml of fluid.

Any tips or tricks worth mentioning? I’ll circle back with my results.

Ordered OEM parts, fluids, and drain plugs from FCP. About $500 in parts but still less than an extended warranty and should hopefully help with long term durability.

[dannyb89]

[QUOTE=Madsen203;31127674]Planning to tackle front/rear differentials, transfer case, engine oil/filter, and spark plugs on 40i next weekend.

While car only have 24k miles on it, I figured the fluid enhange should be quick, easy, and a good preventative given how many posts I’ve seen about these big items shitting the bed early on the X7 - especially being they only hold 6-800ml of fluid.

Any tips or tricks worth mentioning? I’ll circle back with my results.

Ordered OEM parts, fluids, and drain plugs from FCP. About $500 in parts but still less than an extended warranty and should hopefully help with long term durability.

I'm getting ready to do this on my 40i with 50k on it. I'm hoping it's similar to my past X5, which was pretty straightforward.

[Madsen203]

[QUOTE=dannyb89;31128003]

Originally Posted by Madsen203

Planning to tackle front/rear differentials, transfer case, engine oil/filter, and spark plugs on 40i next weekend.

While car only have 24k miles on it, I figured the fluid enhange should be quick, easy, and a good preventative given how many posts I’ve seen about these big items shitting the bed early on the X7 - especially being they only hold 6-800ml of fluid.

Any tips or tricks worth mentioning? I’ll circle back with my results.

Ordered OEM parts, fluids, and drain plugs from FCP. About $500 in parts but still less than an extended warranty and should hopefully help with long term durability.

I'm getting ready to do this on my 40i with 50k on it. I'm hoping it's similar to my past X5, which was pretty straightforward.

Looks to be straight forward. The biggest PITA is removing the underbody shields. If that’s the worst of it, then no biggie.

Probably excessive to do it this early, but it’ll give me an idea of how the fluids hold up long term.

[AvGeek]

It certainly doesn't hurt to do it early, I'll likely do it at 25k miles as well. I've said it before in another thread but my TRX was known to be severely underfilled from factory, and when I did it at 1k miles that was indeed the case.

Here's a thread with some tutorials that might be helpful.

[Madsen203]

Originally Posted by AvGeek

It certainly doesn't hurt to do it early, I'll likely do it at 25k miles as well. I've said it before in another thread but my TRX was known to be severely underfilled from factory, and when I did it at 1k miles that was indeed the case.

Here's a thread with some tutorials that might be helpful.

I wonder if the internals take up some of the oil and thus leave it at a lower level.

[GCR]

Originally Posted by AvGeek

It certainly doesn't hurt to do it early, I'll likely do it at 25k miles as well. I've said it before in another thread but my TRX was known to be severely underfilled from factory, and when I did it at 1k miles that was indeed the case.

Here's a thread with some tutorials that might be helpful.

Pat particular attention to the front diff fluid when you drain it. I'll bet it's a lot darker than the rear diff fluid.

[Madsen203]

Originally Posted by GCR

Pat particular attention to the front diff fluid when you drain it. I'll bet it's a lot darker than the rear diff fluid.

That’s my assumption as well. If it is dark or concerning, I’ll increase interval to 10-15k. If it’s honey colored, I’ll keep same 25k interval.

I should tackle this either this weekend or next. Given it’s Mother’s Day weekend, not so sure this weekend will pan out.

[lumbrjackedpcj]

Originally Posted by Madsen203

That’s my assumption as well. If it is dark or concerning, I’ll increase interval to 10-15k. If it’s honey colored, I’ll keep same 25k interval.

I should tackle this either this weekend or next. Given it’s Mother’s Day weekend, not so sure this weekend will pan out.

Let us know what you find out. I have 19k on mine and am thinking about doing the front differential and transfer case soon as well.

[chicagox7]

Originally Posted by Madsen203

That’s my assumption as well. If it is dark or concerning, I’ll increase interval to 10-15k. If it’s honey colored, I’ll keep same 25k interval.

I should tackle this either this weekend or next. Given it’s Mother’s Day weekend, not so sure this weekend will pan out.

Rookie question: there are places that oil can be sent for analysis. Are there places that transfer case and differential fluid can be sent for analysis? If so, has anyone sent theirs in and can share the results? I get that the color also tells a tale. Just curious if there is more to the story that can learned.

[Madsen203]

Originally Posted by chicagox7

Rookie question: there are places that oil can be sent for analysis. Are there places that transfer case and differential fluid can be sent for analysis? If so, has anyone sent theirs in and can share the results? I get that the color also tells a tale. Just curious if there is more to the story that can learned.

Color is more heat related. An oil sample analysis would be ideal but cost prohibitive. TC fluid is $37. Cheap. The differential, however, is pricy at $100. I’ll look it up.

[admranger]

Originally Posted by chicagox7

Rookie question: there are places that oil can be sent for analysis. Are there places that transfer case and differential fluid can be sent for analysis? If so, has anyone sent theirs in and can share the results? I get that the color also tells a tale. Just curious if there is more to the story that can learned.

Blackstone labs is who I have used in the past. I have never sent in transfer case or diff oil, but I'm sure you could.

[Madsen203]

Update 1:

Did rear differential today. Pulled out 700ml of fluid (which was dark brown/black) and put in 1L. Still not full. This matches others who said the diff and TC’s come under filled. It seems it could still fit another 500ml easily. Going to order another bottle of OE fluid and put it in until it’s filled after it arrives.

Maybe tomorrow I’ll tackle the front and TC.

[Madsen203]

Originally Posted by Madsen203

Update 1:

Did rear differential today. Pulled out 700ml of fluid (which was dark brown/black) and put in 1L. Still not full. This matches others who said the diff and TC’s come under filled. It seems it could still fit another 500ml easily. Going to order another bottle of OE fluid and put it in until it’s filled after it arrives.

Maybe tomorrow I’ll tackle the front and TC.

Fluid condition after 24k mostly highway miles and 2.5 years. Not horrible condition but it’s definitely not super clean.

[Madsen203]

Worked on transfer case today. Was able to get about 200ml out. I used the oil change service function in iSTA but it didn’t seem to move the piece that is in the way of the fill port meaning I was only able to get my 1/4” fill hose partway into it leaving a substantial amount of old fluid in there. At the least, I was able to swap 30% of the fluid and ensure it was topped off. Also reset the adaptions.

Any tips for getting my small hose into the TC to suck out the old fluid?

Fluid looked pretty bad after only 24k miles. Hoping to attempt this again tomorrow with more luck and swap the fluid again. Accessing this isn’t too bad even with the TC support beam installed still.

[Madsen203]

Finished doing the front today. Pain in the ass but mostly because I did it when the motor was still hot. Fluid was dark as I anticipated. Put fresh plugs on and buttoned it up. Likely won’t touch it again until 50k.

With monkeying around accessing full plug, getting diff oil in eye having to flush it, and cleaning up, took under an hour total.

[Madsen203]

Last item: swapped spark plugs. Took 45 minutes and that’s with following proper torque protocol for plugs and coils. While really early, if this offsets a coil failing in the future, it will have paid for itself. I’ll check gap later to see if any changes. Visual Condition was OK with no concerning signs.

Just picked up a Quinn digital torque wrench. Excellent wrench. Much better than the digital Sata I tried.

[Madsen203]

Originally Posted by Madsen203

Last item: swapped spark plugs. Took 45 minutes and that’s with following proper torque protocol for plugs and coils. While really early, if this offsets a coil failing in the future, it will have paid for itself. I’ll check gap later to see if any changes. Visual Condition was OK with no concerning signs.

Just picked up a Quinn digital torque wrench. Excellent wrench. Much better than the digital Sata I tried.

It’s ridiculous to change plugs at 24k/3y, but it runs so much better now! There was always some slight hesitation in first gear and ASS would stumble a little. Now ASS is smoother and first gear is smooth as ice. Time will tell.

I switched from OE plugs to NGK. Very happy and worth the $100.

[admranger]

Originally Posted by Madsen203

Worked on transfer case today. Was able to get about 200ml out. I used the oil change service function in iSTA but it didn’t seem to move the piece that is in the way of the fill port meaning I was only able to get my 1/4” fill hose partway into it leaving a substantial amount of old fluid in there. At the least, I was able to swap 30% of the fluid and ensure it was topped off. Also reset the adaptions.

Any tips for getting my small hose into the TC to suck out the old fluid?

Fluid looked pretty bad after only 24k miles. Hoping to attempt this again tomorrow with more luck and swap the fluid again. Accessing this isn’t too bad even with the TC support beam installed still.

Did you just do the one fluid extraction and fill or did you do a few to "thin" the old fluid out (solution to pollution is dilution)?

Appreciate the write up!

Is it pretty much 2 bottles of rear diff fluid, 1 bottle of front diff fluid and 1 bottle of transfer case fluid to complete the changeout?

[admranger]

Originally Posted by Madsen203

It’s ridiculous to change plugs at 24k/3y, but it runs so much better now! There was always some slight hesitation in first gear and ASS would stumble a little. Now ASS is smoother and first gear is smooth as ice. Time will tell.

I switched from OE plugs to NGK. Very happy and worth the $100.

NGK iridium? Those are my "go to" plugs.

[Madsen203]

Originally Posted by admranger

NGK iridium? Those are my "go to" plugs.

Yea, something like that. The ones available on FCP’s site.

[Madsen203]

Originally Posted by admranger

Did you just do the one fluid extraction and fill or did you do a few to "thin" the old fluid out (solution to pollution is dilution)?

Appreciate the write up!

Is it pretty much 2 bottles of rear diff fluid, 1 bottle of front diff fluid and 1 bottle of transfer case fluid to complete the changeout?

2 bottles (1.5 actually) for the front
2 bottles for the rear
TC fluid came as a 1 liter bottle. I think I’ll attempt pulling fluid again in the future. Maybe each oil change I’ll swap out some of the fluid. Doesn’t take long and will ensure there is some fresh fluid diluting the old. Other write up’s say 700ml

[Madsen203]

Also changed oil (5k since last factory change). Motul oil + OEM filter.

Now I won’t need to touch anything for 10k as the next oil change is on the dealer.

Funny the computer indicated 10k miles until next oil change (just changed from 11k last week) after 5k since last OCI. While there’s has been considerable highway driving, no way would I got 15k intervals on a turbo charged motor with 0-20w oil.