Transfer case questions
 

The car is a 2008 with 135k miles on it.



I have been running in 2wd by disconnecting the two plugs by the transfer case. This is due to trepidation or a vibration that was felt through the car, going to 2wd solved the issue.


My question are:


- how does a stretched transfer case chain manifests itself?


I have an issue where it sometimes does a hard downshift. I also feel some vibration when engine braking. I had it up in the air, and when you shift from D to R or R to D, you can see the rear driveshaft move abruptly towards one of the directions.



At first, I thought the rear differential bushings where bad, but when I inspected those they looked ok. The driveshaft moves like 20 degrees one way, vs 5 degrees the other way when going through the D/R/D exercise.



I was thinking maybe its a stretched transfer case chain, but not sure. It feels like there are some teeth missing from the transfer output to the rear.



Any ideas before I go and buy a rebuilt transfer case?

When last you changed the T-case fluid?

Agreed. I would correlate excessive chain slop to poor maintenance. But the above mentioned symptoms would not correspond to that. I would wager center support bearing, bushings, driveline balance to correspond to vibrations. Maybe the tcase has a worn out bearing--but I'd imagine that would be quite audible.

Sorry guys, I never got a notification on the replies.

To make a long story short, I bought this car from the second owner sight unseen. He claimed a new transfer case was installed as a selling point.

The car was purchased to do a cross country drive with the family and then sell. After putting 10k miles on it, I decided I want to keep it.

300 feet after I picking it up the three lights went off, brake/airbag/4x4. I suspected the guy was having problems and unloaded it on me. No big deal as the car was in really good shape otherwise.

I changed the steering angle sensor, that took care of a couple of lights. But since I had the vibration and I was 4k miles from my house I decided to disconnect the 4x4. That took care of a really bad vibration, but there is the faint one on decel that persist.

Once I got home I went through the whole car. The transaxle is definitely new, but I am sure the shop did not reset the adaptions. The center support bearing is new. Underneath the car looks like it has 5k miles, everything is perfect. I also inspected all 4 axles, which are in perfect shape. I changed the fluid in the transmission, but never did the transaxle.

From digging through Carfax and some research, I believe the first owner had the transaxle swapped for a rebuilt one. The second owner bought the car and kept it for 4 years but barely drove it, probably 3k miles in that period. So I would guess when I bought it, the tcase fluid had 5k miles and 5 years max.

I know I can go ahead and buy the fluid, but I am 100% sure this is not a fluid problem but a mechanical issue. I just dont know if its the tcase or the transmission. I am very mechanically inclined and very well versed in BMWs. Not afraid of removing the tcase, just dont want to take it apart when I am not sure whether its the problem or not.

My next step was to contact Cobra in central Fl and see if maybe I can bring the tcase to him or if he has any ideas as I am about 2 hours away.

Also, I see RocketyMan is in the PNW. In case you are familiar with them, the tcase was replaced by Group 2 Motorsports in Seattle.

I am looking at my notes now, it was replaced at 93000 miles, I picked it up with 113000. So it probably had 10k miles on the fluid.

I'm not familiar with any Seattle dealers. I don't like ANY Seattle dealers. They're crap IMO.

At any rate, make sure the proper level of oil is in the tcase. This helps with longevity and such.

As for the vibration, I suspect the front drive shaft could play a part in that. It's hard to diagnose vibration when using the butt-dyno over the internet. Actual numbers need to be given for a proper corrective action plan.

If you can take off the tcase, it's pretty easy to confirm it's functionality on the ground. Might take an additional hand, but this is what I did when rolling through the pick-n-pull for a good used.