Loose transfer case chain?

[BladeX5]

Hi guys, my X is having a strange behavior since about 2 or 3 months.

I can feel a slight play when going from R to D or viceversa. Also happens when I'm on a flat road and I hit the gas pedal then release it, then again. It feels that the transmission takes some time (about 1 second) to turn wheels all around. The engine revs, but the transmission power doesn't get to the wheels as smooth as it should be.

I have no idea how to explain it, please forget me if it's not well explained.

I believe the culprit might be a loose chain in the transfer case, since my X has 209.000 kms now and I don't think it has been serviced before.

Any ideas are really welcome!

[Sarek]

Loose chain would make a popping noise when u accelerate hard.

[BladeX5]

I heard. But in my case it doesn't do that.
The other thing that seems to cause something like that is shot engine mounts but my mechanic told me they look good. Not much movement when it's accelerated with the brake applied. So, I'm lost.

Again, any ideas are welcome.

[David.X5]

When I first got my X, it was low on tranny fluid and did something similar. Went away after being properly topped off. Have you checked your fluid level?

[BladeX5]

Originally Posted by David.X5

When I first got my X, it was low on tranny fluid and did something similar. Went away after being properly topped off. Have you checked your fluid level?

Actually, yes. The last time it was about 2 quarters low due a bad procedure by another mechanic. Half of it at least is kind of burnt. I want to change as much fluid as possible, without removing the Torque Converter, might be that. Because I can't do a hard acceleration from a total stop, it will emit a weird noise when changing from 1st to 2nd gear, like grinding but not as terrible, but definitively metallic.

I'd do that in a few days. ty

[JCL]

Burnt fluid is bad.

It isn't that the fluid causes the initial problem, it is that it may have been subject to overheating. That means that replacing burnt fluid is unlikely to resolve a problem because something else caused it in the first place, and that root cause is still there. Most likely cause is a slipping clutch, whether from low fluid pressure, or a control or actuation issue. That slipping is consistent with your observation about a delay when accelerating.

[BladeX5]

Originally Posted by JCL

Burnt fluid is bad.

It isn't that the fluid causes the initial problem, it is that it may have been subject to overheating. That means that replacing burnt fluid is unlikely to resolve a problem because something else caused it in the first place, and that root cause is still there. Most likely cause is a slipping clutch, whether from low fluid pressure, or a control or actuation issue. That slipping is consistent with your observation about a delay when accelerating.

Well, it was overheating but not now. The thing is that when I bought her last october, it was in really bad. I had to put a lot of money and work on her to get her in better shape.

So, I started by asking one mechanic to diagnose why she was keeping herself in 2nd gear after a few miles of driving even gently. He told me it was necessary a fluid, filter and gasket change for the transmission. He used ZF fluid which, as you know, is really expensive. I didn't bother about it if it were the real cure to my problem. Certainly it was not.

I finally started learning a lot by reading and I bought myself a scanner cable with INPA included, so I when it happened I went to INPA and looked at the trans temp, to my surprise it was hot, real hot, over 145 Celsius degrees (over 290 F). So, I went back to him, and he told me, you need to swap that transmission... with all the cost involved. I couldn't believe it.

SO, I went back to my research and also went to a good friend of mine shop a little far but I know he wouldn't lie to me.

He inspected her and we found out that the previous owner's mechanic (to not use another word) cut the lines that go to the heat exchanger because the heater was leaking, and he just rerouted them with a piece of crappy copper line (I even have pictures of it).

Anyway, my friend and I changed the lines and the heat exchanger with new ones. That cured the overheating problem, BUT, since I ran out of budget because of the first mechanic, I didn't change the fluid, so we just added some more (2 quarters to be exact).

I've been driving her like that since then without issues, except those 2 I mentioned before. But now I want to solve them. I will change as much fluid as possible and filter again.

Oh, BTW, the original torque converter failed because of the heat and burnt oil before the heat exchanger fix. So, that was another thing this first mechanic told me to do, and he did it. Not for the sake of the love to the brand obviously.

I have put about $1200 just in the trans, because of not knowing anything about it. I think I'd have saved about half of that if the issues would have been fixed in the correct order, but... I can't change the past.

I'm thinking of doing deeper maintenance to the valve body and its parts, like changing o-rings, and so on. I have no issues with the trans at all in terms of driving so far. Just those 2 I mentioned.

We'll see. Let's hope for the best.

[Joshdub]

Sounds like you are on the right path. Sorry to hear about the crappy previous mechanics.

Just to reiterate, it doesn't sound like a tcase chain. If it were loose, you would hear a loud "pop", likely multiple in rapid succession, under acceleration.

[Sarek]

Seems like you need to find a good specialized repair facility to take your x5 to. It will give you peace of mind. Find a qualified place and you will save money in the long run.

[BladeX5]

Thank you all. I'll be looking forward to do another maintenance to the transmission as suggested.

BTW, when I have my car in P, and windows rolled down, I can hear a whizzzzzz kind of sound not loud coming from the transmission, just in that position, so I guess it's a related issue.