Grinding under load - ?Transfer Case? (1 Viewer)

[Steamboat]

Good afternoon!
So I did some searching in the forum and may have come a few conclusions. I'm just hoping for any fresh advice or insight into a problem I discovered this morning.

A buddy and I took our 60's up to place in Steamboat Springs...Buffalo Pass...There's a short F.S. Road - 60.2 I believe...it shoots off the main road about 1 mile before the upper gate. - AWESOME stuff by the way! Anyways, on the way back up a relatively steep and bumpy grade I began experiencing some very load "grinding" that sounded like it was coming from under the car. The grinding sound only occurred when I bounced over large rocks but it was accompanied by a loss of power...at one point I actually stopped moving forward lost all power....had to mash the brakes...wiggle the shifter around and then was able to get moving again.

I have read that this could be something to do with T-Case linkages....and even saw some stuff about motor mounts and fan shrouds. Either way it sounds like I'm going to have some serious research to do. I was able to duplicate the sound...only in 4lo with a tire up against a large rock...so, it would seem that the noise which I can only explain as "grinding" ... maybe a slipping...occurs when in 4lo under heavy load/torque. I also did not notice that the shifters actually moved...they were always in place (never slipped out) oh....and it even makes the noise when reversing up a hill...in fact, that's when it all started...I had to reverse to make a sharp corner (the corner pictured top right)

*sigh*

Oh well...even though this little road was only a few miles long..it was a total blast!! Especially since it's the first time I've actually gotten the '60 in some steeps! - a few pics attached

 

[Steamboat]

Took a look under the hood....wondering if it could be the motor mount fan shroud thing??

Any thoughts?

Thanks so much for any insight!!!!

Ebin

 

[2mbb]

check the drivers side motor mount. I put a jack under the engine and lifted the engine and I could see that the motor mount was split and separated. Of course you either need to put the jack under a solid metal part of the engine (I used a bottle jack) or put some wood under the oil pan to distribute the load.

 

[lovetoski]

As 2mbb says, most likely it's the DS motor mount. Best long-term fix is to remove the torched mount, cut off the bolts, drill a through hole in the motor mount and reinstall with a solid bolt (grade 8). It will never break again, and it'll be cheaper than the new motor mount.

 

[Steamboat]

Hi gang, thank you so much for the feedback! The more I read, the more it does sound like the motor mount is my problem. I crawled underneath and jacked it up but cant seem to see any obvious separation. Will it hurt anything if I crank it up too high? I went high enough to see movement but no signs of damage.....should it be grossly obvious?

 

[Kynot62]

You may want to check the birfs. And backing up a hill with the wheel cranked is not an uncommon place for them to break and you did say this was when you first noticed it. The typical pop doesn't always come with a broken birf. Jack up the front end lock the hubs and start rotating things by hand and listen and feel for grinding, turning the wheels should help as they bind up the birf. And no you won't hurt them spinning them by hand.

Usually broken motor mounts seperate pretty easy when you jack up the motor. No stretch to the rubber part of the mount.

Fan shrouds make a different sound than grinding. Bad sound yes but doesn't sound like grinding to me.

Tony

 

[Steamboat]

.....the Birfs.....I had not even considered that as potential source of the problem!!

Good thing I have not ordered my brake parts yet....Guess I'll be spending the rest of my weekend trying to track down this problem so I can try to order everything I need in one shot!!

Thanks for the great advice, as always Tony! Would if be safe to assume that any grinding or odd noises/vibrations/grinding coming from the birfs would be fairly obvious? I know for a fact that my knuckles are in need of a rebuild since it was a a soupy mess in there when I repacked my bearings a few months ago....would this make the Birfs more likely to break? If I don't feel or hear anything obvious should I go ahead and pull the hub....will I be able to tell if the Birf is broken from that far tip?

To be sure I rule out the motor mount thing....should I have checked the rear mount as well? Seemed like everyone talked about the DS front so I didnt even bother looking at the rear.

I just bought this baby in March of this year....this is the first time I've really taken it anywhere where 4wd was totally needed! But, with that, I have no idea what it's been through for the last 245,000 miles......

Is there any way to check if my Transfer case is the source of the sound....are there any other sources I should be investigating?

**I hear that one of my neighbors is the head mechanic for the city....could be time to wheel a keg of beer to his front door and introduce myself!!

Thanks again everyone....I'd never get out of the driveway without your help!!

Ebin

 

[lehiguy]

My TC pooped out several years ago, displaying similar symptoms as you describe; nasty noises under load. It turned out that the idler bearing had ground about 1/8" into the idler shaft. Is it common for the seal between the TC and the trans to fail and, in complete defiance of gravity, the lube in the TC ends up in the trans. This of course accelerates failure.

 

[Steamboat]

oh man lehiguy....I better do some more reading....everything you just said went totally over my head!

How did you find that problem...do you have to actually take the t-case out/down and open it up...or is there a magical way of testing this problem without totally diving in?

thanks,

 

[Kynot62]

Yes the rear mounts do break and make bad noises so check it as well.

Sometimes it's obvious with a birf sometimes not. If you can't isolate the grinding to any other place I would go ahead and pull things apart to look. And since you mentioned that you had a soupy mess when you repacked the bearings you probably do again if you did not replace the inner axle seals or what most people call the birf seals. They are what seperate the grease from the 90 wt.

And a word of caution about a broken birf. Just unlocking the hub doesn't solve the problem even temporarily. The birf is still moving back and forth when you turn the wheel even if it is not spinning and it can lock up your steering if the break is too bad. We learned this when my buddy broke a birf and we drove back to camp in 2WD. Next day when it was time to head home his rig would only turn to the left, not so funny when you think about it.

If it does turn out to be the birf trying to determine the exact cause is difficult and as you mentioned god knows what happened with it before you bought the rig. As for knowing if it is bad, you may find the inner star broken or possibly just a crack in the bell.

All this has to come apart for a knuckle seal replacement anyways so if you are going to tear it down have all the seals and gaskets handy and combine the two jobs.

Quick way to check the t-case is to drain it and look for metal on the magnetic plug. Grey sludge is common, shiny chunks of metal is not. Like Lehiguy mentioned no oil in the tcase and an overfull tranny is a bad thing. You should be able to spin the tcase by hand if you pull the driveshafts but you wouldn't be able to put a load on it so you may not hear or feel any grinding

Tony

 

[Steamboat]

GREAT stuff!!!

Gotta work tomorrow...had not planned on a possible steering problem....now I'll be sweating all the way there - only 5 miles on pavement - not like that will make a difference knowing my luck though!!!

I'll cross my fingers since I have no other choice for now...but come Monday I'll be draining the t-case fluid and testing the Birfs. - not to mention I still need to get my rear brake parts on order - ugh -

Thanks SO SO much!!

 

[FJ60Seth]

If you can't isolate the problem, I'd tackle the front axle before the tcase. It sounds like the front axle needs to be done anyway and there's tons of front axle posts to help you. The tcase is a more ambitious project. Personally I'd change the motor mounts just for the peace of mind.

 

[Methusalem]

The sound you hear can't be the fan against the shroud. When the fan hits the shroud, it sounds like somebody is using a chain saw on a Jeep.

 

[Heartworm]

These grinding sounds are hard to find! It certainly looks like your fan has hit the shroud at some time in the past. Because this happened in 4LO, I would also suggest that you look at the possibility that the 4LO shifter is trying to partially come out of gear. Usually the damn thing just "pops" out completely, but it could be incremental. I had the 4LO jumping out of gear problem and it was resolved by cutting the undercarraige rubber boot to the 4WDshifter lever. The one you see on your floorboard conceals a second boot that is there to keep noise, dust, mud, etc. from causing problems. With time, the thing gets stiffer than a wedding prick and causes a steady pressure that pushes the 4LO out of engagement. The quick solution is to give it some relief with a pocket knife.

If you can set up a diagnostic trial to replicate the noise, it will help you pursue its cause.

 

[Magic Spool Bus]

Was this ever resolved? I’m having a very similar issue I’m 1991 80 series. Grinding in 4lo in high load situations. Very hard to chase down the issue.

 

[at4fj60]

I'm getting what sounds like a similar grinding noise but it seems to mainly happen when making a right turn while shifting and/or hitting a pot hole if on pavement or, like today, bouncing on a rough trail (Peters Mill Run going north).

Wondering if anyone has any advice on this?

 

[nohermosa]

I recently had a grinding coming from the rear of my truck. It ended up being the rear driver side bearing wearing a groove into the half shaft. Easy to check by jacking it up and seeing if you have any slop (up, down and sideways) in the wheel. Also to note the grinding would go away when I stepped on the brakes.
Not sure if this is the same problem, but just thought I would share my experience.

 

[2mbb]

I'm getting what sounds like a similar grinding noise but it seems to mainly happen when making a right turn while shifting and/or hitting a pot hole if on pavement or, like today, bouncing on a rough trail (Peters Mill Run going north).

Wondering if anyone has any advice on this?

check to see if your fan is hitting the shroud. If the tips of the fan are shredded, then you should check your motor mounts.