Help needed finding Transfer Case Parts

[DSSA]

Originally Posted by trader4

I recently replaced the chain on my TC and was looking at sources for
the chain, seals, bearings, etc. I didn't need the part you're talking
about, but I did see that there were not many sources for TC parts
other than the chain, seals, plugs. And I spent a lot of time looking
at what was out there. I too only saw what you're looking
for at Cobra.

The TC case here had 160K miles and the splines, while rusted,
were fine. I think you're assuming that if the shaft splines go, then
the female end on the TC will also be shot. In doing my TC research,
it looked like that definitely happens in some cases, but I'm not
sure it happens in all cases. I agree that they would be suspect
and certainly should be inspected, but I personally would not be
on the costly and difficult repair path without inspecting them.
With it as is, from what I see, the worst you have to lose is the
car becoming disabled again because the splines on the shaft are
shot again and the TC side is too. But then from a repair point,
you're where you are now. You'd need the $400 TC part. And
you'd cut off the fouled spline end of the shaft and replace it
with the longer aftermarket part like you intend to do now.

Another data point is the BMW dealer did what they did. If
they had experience that says the repair is going to fail in
a short time, taking the new shaft with it, then I would think
they would have told your buddy that it needed not only the
shaft, but also the TC replaced too. BMW is certainly not shy
about handing out big repair bills.....

IDK how many miles your car got before the splines went, but
if it's typical high miles, I think you have to wonder if it's worth
it doing the extended shaft thing at all. In my searching, I came
across people talking about the issue and there were people
reporting that the new extended splines failed in only a year
or two. I also saw someone who had been selling them stop
selling them for that reason. Again, I didn't look into it that
extensively, because it wasn't my issue. Those people who
had failures may have been using the original TC female end.
On the other hand, it would seem the extension seats about
twice as far into the TC, so the ends of the new splines should
be about as far into the unused part of the TC female end as
the original shaft was. So, those early failures with the extension
are a mystery to me.

Back to the parts, this is what I found for parts for the NV125,
not sure which TC is on your car:

Chain - Multiple sources, including Cobra and Ebay. They
all seem to be Borg Warner

Seals - Multiple sources, FCPEuro, other typical BMW vendors, and BMW

Sealant - I used Permatex automatic transmission rtv sealant

Fluid - Dexron ATF

Some people may get away fine with the original output gear in the t-case if they have a failure. However, when you strip the splines off of the drive shaft, the splines remaining in the t-case *are* going to experience increased wear (along with the wear from the rusting that seems to contribute to the initial failure). To what extent? Like snowflakes--no two are going to be exactly the same.

What I *DO* know is that if you sample 100 people with this failure that just replace the drive shaft, and only two of them have an issue with the output gear splines failing and taking out the new shaft--I will be one of those people.

I admire your outlook on BMW's processes at the dealer level, however, having a background where I've worked with many dealers and with a few manufacturer's (on top of reading about other people's BMW dealer experiences), assuming that they're going to do the best procedure in every instance like this is not something I can get on board with.

They (like every dealer) weigh and balance profits on repairs, and getting the job. I can assure you that some (not all, as there are some really good service writers and techs out there) would happily sell a new shaft at full list that they can install quicker than book time as opposed to hard-selling someone the higher cost fix. If it fails? "Well, it looks like you needed a new transfer case too, but we have no way of knowing that for any certainty" (which if the splines don't look too visually damaged--they don't). It's a lot easier to sell a profitable, quick job, than it is to sell a job that will equal 1/2 to 3/4 of the vehicle's overall value.

I have yet to get the car transported and up on a lift, so I can't say for certain at this point, but it seems as though this car/situation is a supporting case for this. The shaft was replaced about a year and 4,000 miles ago.

While you seem to be correct in what you're saying about the new shaft seating into the formerly unused splines just as far as the original did from what I've read thus far, that's another point--there is a seemingly high failure rate with said amount of engagement. While rust is certainly a contributing factor, the load to engagement area is less than ideal. I'd prefer to start out with that extra engagement area from the start as opposed to getting back to the limited amount from the factory.

I appreciate your logic with the aspect of "giving a try" with the longer splines. It does stand to reason. I would just prefer to try to repair the system as completely as I can and (hopefully) not have to worry about it again. At $400 extra, the output shaft does make me pause and examine the situation, I'd certainly rather not spend the money unnecessarily, however with the aspect of having the t-case out, on the bench, and torn down making the gear replacement cost me an extra 15 minutes time vs. an additional 6-8 hours to do the job over again, I'm leaning towards just buying it from Cobra if I can't find it elsewhere cheaper.

I think I'm just remembering my friend's 540 that I had to put a used transmission in (auto, GM tranny) and found that the replacement he had purchased was bad. The 2nd time around it only took me about 2-2.5 hours, but I was still hating life at the time. ;-)

Josh

[DSSA]

Sorry, someone had asked about mileage (if it were high).

This X5 currently has 59K on it.

[bcredliner]

I agree with Trader4. This problem is usually associated with high mileage vehicles which yours is not. I would rebuild the transfer case as you intend to do. I would not go to the longer spines. Reason being the stock parts, other than the plastic gear, usually last well over 100,000 miles. Maybe the previous owner was pulling stumps with it to tear it up that soon, who knows.

[bcredliner]

Originally Posted by trader4

He's not intending to rebuild the TC, nor is there any reason to
do so from what I've heard. His only interest in the TC was concern
that the female spline part on the TC was compromised by the failed front shaft that the dealer replaced. That *might* be true. The dealer
apparently didn't think that the TC part was a problem, they replaced
just the front shaft. But if he
does nothing and it fails someday, other than being stranded on the side of
the road, the cost of the eventual *possible* repair is the same as
if he does it now, preemptively. That was my point.

Oopsie, I missed the point it had been repaired. Assuming annual mileage in the 15,000 range I would leave it alone and not worry about it. As you said "might" go.

[DSSA]

My apologies, as I guess I wasn't very clear on the status of the car currently.

The dealer fixed the spline issue by putting in another shaft, however, there's now an issue about 4-5K miles later. That is how I have purchased it.

The previous owner drove it as a car, no off-roading, no towing. Commuting to work and back on the highway.

I just got back from picking it up with the trailer as my towing company fell through for the day and I wanted to get it out of the previous owner's way.

Now that I've gotten to drive it (pre-purchase, I was only able to drive the car about 75 feet in an busy suburban area with lots of kids playing in the area), while I'm still very certain it's a transfer case issue, the grinding noise I hear (now that I have room to actually drive it) sounds more like a loose chain hitting the casing.

Hopefully that's all I'll find as the issue, but I'll still be examining the splines on both parts once I find lift space to put it up and pull the transfer case. I'm also ordering the actuator gear to do while it's out.

[upallnight]

Originally Posted by DSSA

My apologies, as I guess I wasn't very clear on the status of the car currently.

The dealer fixed the spline issue by putting in another shaft, however, there's now an issue about 4-5K miles later. That is how I have purchased it.

The previous owner drove it as a car, no off-roading, no towing. Commuting to work and back on the highway.

I just got back from picking it up with the trailer as my towing company fell through for the day and I wanted to get it out of the previous owner's way.

Now that I've gotten to drive it (pre-purchase, I was only able to drive the car about 75 feet in an busy suburban area with lots of kids playing in the area), while I'm still very certain it's a transfer case issue, the grinding noise I hear (now that I have room to actually drive it) sounds more like a loose chain hitting the casing.

Hopefully that's all I'll find as the issue, but I'll still be examining the splines on both parts once I find lift space to put it up and pull the transfer case. I'm also ordering the actuator gear to do while it's out.

If I'm not mistaken, you have a NV125 transfer case and the actuator gear is for the later transfer case.

[DSSA]

Originally Posted by upallnight

If I'm not mistaken, you have a NV125 transfer case and the actuator gear is for the later transfer case.

You are absolutely correct.

I need to get this thing up in the air today before I make any further moves.

Thanks!

Josh

[DSSA]

Originally Posted by trader4

If it's the TC chain, the classic symptom is several loud snaps,
like gears stripping, when you accelerate from a stop. With
gentle throttle, it can be avoided and with sharper throttle,
you will get it. The chain here was slack to the point that it
was starting to rub on the case of the TC, but there was no
noise from that while the car was running. All that was heard
was the few snaps when starting out.

You can check the TC chain very easily on the NV125. Just
remove the drain plug and look inside with a flashlight.
The chain goes right by the hole. It's on a sprocket there,
but you can still put a thin screwdriver or ice pick in there
and try to move the chain off the sprocket. If there's play,
you'll see it. The one here was obviously loose when inspected.
Another indication would be if there is silvery goo in the fluid
which you get if the chains is so loose it's rubbing against
the case, wearing it down.

I actually did just that about an hour ago. All of my lifts are currently tied up, so I pulled it up on ramps to check the chain tension.

The chain doesn't budge with a flat-head screwdriver.

However, the bad news is that with the front end up on ramps, I still only drained about 1/3 of a pint out of it (1.1 pints seems to be the capacity). Fluid, while smelling a little burnt, was red and clean.

I'm going to toss some fluid back in it, mark the front drive shaft and output gear with a paint pen and see if it moves at all.

Side note: The transfer case has two different types of sealant on it, so someone has been in it before.

Additional side note: I'm now hearing the ABS motor run after removing the key. So it looks like I have to have the module rebuilt as well. I guess these cars sometimes live up to their name of "Worst Used SUV to Buy Used".

I hope after sorting out the bugs, I enjoy driving it. I have yet to actually drive one. So far however, I'm glad I bought it to replace my current "local driving" car (528iT with 240K). I think the Sequoia/Land Cruiser hunt will continue.

[DSSA]

Finally got a chance to open up a lift here at the shop and get this thing up on it this morning around 11am.

Found a couple of things:

1) Front, right axle is new--also wiggles quite a bit. Pulled the axle out, and discovered that whomever performed the "repair" pulled the bearing out of the carrier with the old axle, and just stuffed the new axle in. Axle was just floating in there, and cracked the outer race in the carrier assembly. Called the local BMW dealer and will have one monday (along with a new axle as the flange on the axle also separated.

2) Previous repair on the splines for the front drive shaft was worse than I expected. Place "claimed" to have replaced the front axle and I was worried that the output gear splines were worn as well. (Similar to customers who want a new synchronizer tossed into a transmission to fix their shifting issue and ignoring that the sleeve/meshing teeth on the gear are also ground flat--temporary fix at best). What they actually did was weld an inch long coupler on to the front of the output shaft with matching splines (extending the output gear).

3) Chain is loose in transfer case as well.

Problem arises when I pull the transfer case (air tools and lift make it a quick job). I disassemble the transfer case on the floor to the point of pulling the output shaft gear out of the case. Surprise, surprise, their "professional" welding skills (imagine silly putty thrown at a wall and then the resulting blob somewhat ground down) make the shaft too large in diameter to pull through the seal.

So, end result, I'm either replacing the output shaft gear (cutting out the old "repair"), or looking for another core. Front drive shaft splines will have to be addressed as well.

1 point for BMW engineering and longevity, 2 points for hack mechanic fixes.