Transfer Case Growl

[Morty]

Hi all. New to the forum. I've enjoyed and learned a lot from lurking around for the past few months and reading all of your posts. I have a problem that may or may not be unique, but my searches haven't turned anything up. I have a '78 FJ40 with a SBC and an AA conversion kit. It is making a growling noise and vibration on deceleration. The source seems to be the transfer case, and it only happens when in 4 wheel drive. The t/c was rebuilt by a previous owner about 5K miles ago. The fluid looks fine. I realize that the AA mount that bolts to the rear of the t/c makes a pretty solid connection with the frame that may transfer more vibration than the stock configuration, but I wonder if others of you with SBC and AA have noticed the same growling noise and vibration.

 

[Poser]

Welcome.


What is the condition of the front drive shaft?

If you push up and down on it at the slip and stub, does it have any movement?

When was the last time the front shaft was greased?


If you push up and down on the shaft where it attaches to the transfer case, if there play there? How about at the front diff?


Are the front driveshaft bolts tight?


Any or all of these could make a noise similar to what you have wrote about, while in 4wd...and decelerating...


Good luck!


-Steve

 

[Morty]

Thanks Poser. I'll check that out.

I consider it an accomplishment that I got a response from you that didn't refer me to the FAQ.

 

[fng55]

check the parking brake drum for play to... when mine growls it means i've blown another set of t-case main bearings.
hope you have better luck than i do with it, carl

 

[RUSH55]

I had to run with front wheel drive from a trail to home. When decelerating or when "floating", my t-case made all kinds of rumblings. But this was around 45mph and above.
This was when I was running the stock 4spd. t-case.

 

[Black Dog]

My 73 fj, and a friends 78 makes the same transfer case noise in four wheel drive when you decelerate. His has done it for years and nothing has exploded yet. I just figured it was the nature of the beast. But, I'd be curios if there is a cure before it does explode. My friends is bone stock, and mine is 350/400.

 

[peesalot]

If it is at about 40 mph and happens when you lift and kinda lessens during float and goes away if you barely pick it up then it is your drivelines. Check slip yoke , u joint( I bet rear at tcase is loose) , rear third yoke , tcase outputs , and lastly driveline bolts.. Somewhere in those it is loose. Mine does it pretty bad when lifting for an offramp and it is just a little play in slipyoke, If I grease it with old school drum brake grease and put new TOYOTA ujoints in it goes away for about 300 miles.

 

[1Fine40]

Quick question, do you have a lift kit on it?
When I lifted mine, it changed the pinion angle, which made the driveline cause the same sound you refer to...my solution was a CV driveline after some other ummm, adjustments. (If you consider a cut and turn of the knuckles an adjustment...) No noise, no vibes now.....

Cheers!

 

[Morty]

I do have a lift. OME.

 

[PabloCruise]

I thought t-case noise was due to worn bearings on the idler shaft? Or worn idler shaft itself?

I had some drivetrain oddities due to a spun shim in the rear pinion, and a loose stake nut on the front pinion.

Good Luck!

 

[Morty]

Front diff s**t the bed. Pulled the drain plug and it was full of metal shavings. Thanks everybody for the help in pinpointing the problem.