Hey Forum,

I was going to go for an oil change tomorrow, but my Crossfire is about to hit 80k miles. However, I have a coupon from the dealer that would change my front and rear differentials for free. However, I may want to save this one, but when should I change the fluids? I've heard it was every 40-60k Miles, and I don't recall myself ever changing it.


Thanks again!

 

This is a joke right? You're joking?

 

OK, I feel bad in case this was a legitimate question.

Check you owner's manual. It probably says "lifetime fill", I don't know, I haven't checked. I recommend changing the oil on the REAR differential every 75,000-125,000 miles, based dramatically on driving conditions. Frequent racing may require more frequent changes. You can't change the oil on the front differential, because there isn't one. The Crossfire is not all wheel drive.

 

I would just ask them to change the front now and wait until 200k to do the rear

 

You guys are so mean!

 

Never...unless you have an issue with the differential hardware and dismantling is required.
Similarly, replacing transmission fluid with preventative maintenance in mind, can lead to more harm then good. Differentials and Transmissions are in the catagory of "if it ain't broke, don't fix it" category IMO.

 

I agree with you in a lot of cases.

With transmissions, FLUSH (not change) it every 75-100k, or not at all. You don't want to go from super dirty to super clean fluid at once.

For open differentials, the factory fill should be good for the life of the car. Clutch type limited slip differentials contaminate the fluid as the clutches wear, so those should be changed every 75k or so.

Frequent burnounts, racing, extreme & driving conditions can shorten the oil's life.

 

The owners' manual says change the trans fluid at 80,000 miles. I had it done at the dealer last year and they only put in 4 quarts so I'm figuring that they just dropped the pan and cleaned the filter and refilled what was lost from the pan.

 

I'm guessing automatic transmission? If I recall, standard transmission is "filled for life".

 

Sounds like it. When I flushed the transmission on my ML320 (same transmission I am pretty sure) it took 18 quarts before the the fluid was coming through clean.

 

Yep, the auto. But now the manual states that it never has to be done again. I guess there's an exceptionally long "break in" period.

 

Eh, I disagree. I'm not one to drive around with dirty fluid that's been used for 100k miles. All fluid wears out, regardless of the owners manual.

 

If you take your manual transmission equipped Crossfire back to the dealer and complain about it being hard to shift, I think it's pretty much standard procedure to replace the ATF fluid with synthetic motor oil.

 

I'll be thrilled to get another 100K out of the car as it's got 85K on it now.

 

I have 110K now, so far so good.

 

Any reasoning behind this? I am simply wondering. I did both my tranny (manual) and diff around 50K and the stuff came out pretty nasty, glad I did it. The car seemed to drive a little easier and it greatly improved shifts to go to Mobile1 full synthetic in the tranny.

I would say do it as often as you like, if it is a coupon for free and it is an SRT, get it done for sure...

 

I can't provide any scientific proof just real world experience aftert 40+ yrs of driving. When younger, I drove some real high mileage beaters and never touched both the transmission nor the rear differential with no failures that I can remember. I currently own an award winning '82 Volvo 240DL (all original, original owner) with over 230,000 km. Again, have never replaced the tranny fluid nor the differential, however I did replace the clutch a couple of years ago, only because it was starting to show much wear, and while replacing the rear engine seal, it made sense to replace the clutch at the same time. Also, I recommend not touching the tranny fluid (assuming their are no issues) as again, I have witnessed first hand, perfectly running cars with auto transmissions, that had their owners replace the tranny fluid (automatic transmission) because they felt it was the right thing to, only to cause days/weeks later, catastrophic transmission failures....my understanding is that most differentials are factory sealed with no access to either check or drain the fluid....just my two cents!

 

Exactly what I asked for

I can understand on a car that is very old or has a crazy amount of mileage on it and has never been done, but I think for a car that is newer and can be taken care of properly its whole life, it is a good idea. Newer vehicles, with all their computers and sensors, also have stricter tolerances than older cars. Again, I do not have the ultra old car, or been driving for 40+ years, but I have been around a car or two in my time, and worked at a few dealerships

I also race my cars from time to time, and that makes a big difference, so if there is spirited driving involved, as with the OP and his SRT-6, I would highly recommend changing the diff after what I pulled out of mine at 50K.

 

Heat would be the enemy here. It could break down the viscosity. The other thing is wear. Little micro size pieces of metal. I think changes at 100k would be good as long as it is a complete drain and flush or you didn't accomplish much. Final thing is have the fluid you want to check sent to the lab. We did on the big rigs. Gives you an idea of wear items like bearings. If it comes back good no change needed.

 

Joshnosrt6. A lot of those coupons have hidden agendas. XF takes 8-81/2 quarts according to who you believe. I use 8 1/2. Dealers usually only give you 5. Same goes on filters etc. But you really don't have a front diff. And if you do hang on to that 1 of a kind. It's priceless like some of the characters on here.