Trans or TC Screeching Noise - Freezing Temps (Video)

[howeitsdone]

To preface: I've owned the truck since June and all winter it was kept in a garage. So it's never been left out in freezing weather for extended periods, only throughout the day when at a store, restaurant, etc. But was never cold-start outside of the garage all winter.

 

I camped up in the mountains where is got down to about 25f or so overnight. When I was ready to leave, the temps were maybe around 30f, so it never got above freezing. Started up fine no problem, but there was a rubbing & screech coming from the transmission tunnel. You could hear something turning. The clutch is new within the last month too. Of course it got worse while pulling out of the camp space. I made it across the road to get it in the sun and when I depressed the clutch, it died. Tried to start it up but wasn't working.

 

Ended up sitting in the sun (8,500ft so get's hot quickly) for 10 minutes or so and fired right up. The screeching stopped maybe 5 or 10 miles down the road and was non-existent except for a random time climbing a hill in 3rd. Hasn't happened since I returned either so tells me it's freezing related.

 

I'll note that the trans was in neutral and it was still happening. I put the TC in neutral and still happening too. While the TC was in neutral I could move the shifter into gear without depressing the clutch too which I thought was weird.

 

 

[gogmorgo]

With the transfer case in neutral you don’t have anywhere near as much inertia for the synchros to fight to match engine speed. It’s not super surprising to me you can get it into gear without the clutch, but I don’t know if I’ve done it myself. 

 

Pretty difficult to diagnose a sound from a video. I’ve heard blower motors make similar noises on cold startup, also wipers, but those aren’t in the trans tunnel.
You checked all fluid levels? Made sure no wildlife crawled up somewhere nice and warm for the night? Unless there’s water in something I can’t imagine simply being below freezing causing any of your transmission bearings to do that, and then recover when warm. I’ve cold-started my Jeeps below -40 even and never heard anything like that from the trans. Not to say it can’t happen. 
It it was my own vehicle I’d probably shrug it off and wait for it to happen again before worrying too much, provided I knew everything was visually okay underneath, including fluid levels. 

 

[howeitsdone]

10 hours ago, gogmorgo said:

I’ve heard blower motors make similar noises on cold startup,

This sounds like it could be exactly that now that I think about it. If shifting has nothing to do with it then I wouldn’t think transmission. It’s just so crazy that it sounded like it was coming from the tunnel so I would never have guessed otherwise

 

too bad it’s not like I can just go replicate the noise unless I decide to camp in freezing temps again 

[JYau]

That's a strange noise but if you think it's coming from the tunnel, one thing I would check the speedo gear cable. I have a noisy cable in my MJ and it gets better as it warms up. 

[gogmorgo]

On 5/22/2022 at 9:55 AM, PocketsEmptied said:

It’s just so crazy that it sounded like it was coming from the tunnel so I would never have guessed otherwise

 

This is why it's so difficult to diagnose a noise from a video. You're the one who's with the vehicle and can tell where it's coming from. Blower motor noise would be more bottom of passenger side dash, which would be in line with trans tunnel as a general area, but it's not like I can tell you what you were experiencing firsthand. It's also sometimes hard to tell a specific source of a noise just by hearing. If it were me I would be turning stuff off and on, getting out of the vehicle and under the hood, underneath, trying to figure out where it's loudest, etc. If it's not making the noise now and you can't find anything else obviously wrong there's not a lot to go on.

[schardein]

I'll relate a cold start story just for fun.  I live in Missouri, and it doesn't get super cold here, but it does dip into the negatives from time to time.  I had parked my 2001 Chevy 2500HD (330,000+ miles at the time) in my shop overnight.  It got down to about -10 F that night.  When I started it, got a strange rubbing noise from the engine bay.  It stopped after about a minute.  I drove to work, drove during lunch, drove home.  Got home, crawled underneath and started looking.  The engine cooling fan had rubbed on the bottom of the fan shroud, actually wearing a hole in the shroud at the very bottom.  My theory is the almost 20 year old motor mounts contracted enough in the cold to let the fan hit the shroud.

 

And just to mirror that story, when I first bought my 91 XJ, I would get these strange noises as I drove down the road.  Finally found the transmission mount was completely oil soaked and sagging, and also allowing the transmission/transfer case to "bounce" up and down almost 2 inches as I drove down the road.  Replacing the mount fixed the strange noises.

 

If it isn't the blower fan, you might want to crawl underneath and just look around, and push and pull on things.