Ricky, at your mileage, I would not do that. Instead, remove front drive shaft, inspect, clean and put fresh grease on the splines. As far as TC chain replacement – I didn’t see any failures on 3.0 cars. It looks like higher engine torque and lower final drives gear ratio (4.10 vs 3.64) on 4.4 pre-facelift cars is major contributor to stretched TC chains. My car is also 2003 3.0 and I inspected / lubed front drive shaft at 115k miles when I bout the car and once again at 175k. The first time I remove it - it was completely dry and rust started to develop. There was slight (normal) wear on the splines. Not that bad to justify replacement. As of today, at 201000 miles, both TC and drive shaft perform without issue.

Good call, I will look into that. I only say it, and maybe this is because my car is a 3-pedal that its harsher on the Tcase, but sometimes if I'm on the highway and coasting, and then I get on the pedal, there is almost like a harsh transfer of power, like the smallest of delays, could be motor mounts slightly worn as well, but I do notice it and thought of something like a Tcase chain or driveshaft issue slowly rearing its head. However, good call on greasing it for sure and you are like me - being preventative! I just worry about the lesser contact on the shorter shaft long term, even if its greased - I think it is a bad design from BMW and should have had more spline contact from the factory.

I am in total agreement about design shortfalls, especially AC drain dripping condensation on the spline joint. Also, I am not comfortable on installing replacement shaft that is only ½” longer on cars where original shaft partially worn. It will effectively put most of the load on the extended ½” portion of the shaft. The original length of the splines in the TC will have less contact with new shaft due to higher tolerances caused by wear. The full 1” version will provide at least same size initial contact surface as new factory TC / drive shaft combo.

I got completely hosed by an eBay seller of longer splined front shafts. Hope you have better luck.

If you have spun yours, you need at least 3/4 longer, as the transfer case female splines are damaged and you need to engage the undamaged part way in there. Changing the output piece on the transfer case or a used transfer case would help

Ricky, in regards of harsh transfer of power during coasting – it is always more noticeable on three pedals cars due to lack of torque converter cushioning of the drive train. Besides all common points such worn flex, CV and splines joints – additional harshness may be caused by partially worn springs in the dual mass flywheel. But again, at your mileage it is too early to think about new clutch job.

^^Just want to tell you thanks so much for not making me think I'm crazy! I will drop the shaft and clean and grease the splines so hopefully I don't have to worry about the driveshaft or T-case for a solid 100k!

:iagree:

Your longer splines won't do much good without having enough mating surface on the TC coupling. In fact, you'll probably wind up with less than the OEM length actually engaged into properly fitting spline material.

2002 X5 3.0 294,438 miles (Front driveshaft and TC replaced at 136,000 miles)
2014 428i 14,700 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

So, I'm under the X5 now, looking at how to put the new shaft in with extended splines. I can remove the rear drive shaft guibo, loosen the TC subframe bolts, but how will the entire assembly slide back? Do I need to spilt the TC from the transmission? Drain the fluid and remove all the torx bolts that mate the TC to the transmission?

Edit: Looking at pictures now, I see there is not fluid in the TC to transmission mating, so just removing those torx bolts and allowing the TC to slide back might do the trick. I'm going to try that.

I think you have the right idea. The fluid is contained in the transfer case, and those bolts can be loosened without it leaking (or the trans leaking). If you have a transmission jack, put that under the transfer case to help hold the weight.

Remember that the rear end of the transmission/motor assembly is held up by the transfer case, so you have to do something to support the transmission and distribute the weight (not a single jack stand under the transmission oil pan - load is too concentrated like that). I used my floor jack and a piece of 2x4 to distribute the load.

(Note, edited to correct all the places I wrote "diff" when I meant "transfer case".)

Thanks that is good info.

I've removed the rear guibo and loosened all the subframe bolts. I had to cut one of the exhaust hangers. The owner before me welded muffler deletes in there and made it difficult to get at the subframe bolt.

Have to run to the store for a torx bit, mine are deep sockets and there isn't enough room to fit a ratchet on there.