FJ60 25mph+ drivetrain whine (1 Viewer)

[MBurroughs]

Hello everyone.

I'm chasing a drivetrain whine on my FJ60. Tomorrow I'm going to get the truck up on the lift and start exploration, because everything I've tried so far has had no luck. But I wanted to ask in case my symptoms are identifiable to someone with more knowledge than I have.

The truck is an '85, running a 6.0 vortec and a built 4L65E that I purchased as a freshly rebuilt unit from a shop that specializes in them.
I have the factory transfer case, which I did a total rebuild on, following the FSM, and finished the job with no hiccups and nothing seeming out of place.

Symptom:

The truck begins to whine somewhere between 20-30mph, and the whine is high pitched. It grows higher and louder with speed, and to my ears, sounds like a gear whine, but what do I know?

The whine is only under load - acceleration and deceleration. Under a steady cruise with minimal throttle it tends to fade away. The whine will also disappear if I shift into neutral while driving.
The sound does not "shift" with the transmission. It's a completely linear sound.

I assume it must be the transmission, the transfer case, the rear driveshaft, or the rear diff.

I never drove the truck before the swap, as I bought it not running.

I assume it's not the diff, as the sound seems to be coming from around the shifters, but anything is possible.

Do these symptoms sound familiar to anyone else? Gut instinct tells me it must be the transfer case, since I did the work on it.

I've checked my fluids in both the transmission and the transfer case and they're both full with brand new fluid.
I used 75w90 in the transfer case.

I greased the zerks on the driveshaft.

So far, no luck.

Any other tips, tricks, or things to look for so I'm not going in blind?

Thanks as always.
Mike

 

[RustyNailJustin]

Got a pic of the rear driveline angle?

 

[MBurroughs]

Got a pic of the rear driveline angle?

I don't have one handy, but can post one in the morning.
Think pinion angle could be a culprit? I wouldn't imagine it would cause a high pitched whine but I wouldn't be upset if that were the answer.

 

[RustyNailJustin]

The part that made me bring up the angle was the noise being there on and off power. Not being able to actually hear what you are hearing, start with the basics.

 

[MBurroughs]

I'll provide a photo tomorrow morning then. I'll also measure the pinion angle difference between the transfer case and the axle.

 

[MBurroughs]

Just updating for anyone who finds this thread via searching in the future.
I got the truck on the lift and it is definitely the transfer case.
Not sure if it's something I got wrong on the rebuild, or if it was a preexisting condition when I purchased the truck.
I'll report back again once I find out.

 

[cruisermatt]

You've gotta have a bad bearing or bushing.
I've ran one dry and mine currently has a bad output bearing and it still makes no noise.

 

[MBurroughs]

I rebuilt it with all new bearings and such. I have to imagine I have it shimmed or torqued incorrectly. Otherwise I'm clueless.

 

[MBurroughs]

So I went through and shimmed/torqued the shaft correctly but it doesn't seem to have solved my problem.

I have noted that the whine seems to go away in 4WD, but I need to drive it more to know for sure.

I'm really scratching my head. And quite disappointed.

 

[fjdemon]

Possibly a bad new bearing? I have a Silverado with a new clutch kit installed and the throw out bearing is whining....parts today are hit or miss.

 

[MBurroughs]

Just following up with this thread in case anyone in the future finds it through searching.

I've continued to try and solve it, with no luck at all. After having the transfer case rebuilt again by a reputable shop, and having them replace anything that even - looked - like it could use replacing, she still makes noise. I'm beginning to think its the bearing supplied by Advance Adapters, but I don't have it in me to tear everything apart again.

No harm in turning up the radio a bit!

 

[stevebradford]

Check the rear diff plug for metal. The diff gets extra hot and wines when the bearings are on their way out.

 

[MBurroughs]

It's absolutely coming from the transfer case or back half of the transmission. I've had it on the lift and have listened with a stethoscope.

 

[stevebradford]

No harm in checking... noise travels strangely. Especially such an easy thing to check.

 

[MBurroughs]

Of course. I do appreciate it.

 

[stevebradford]

Actually a good thought have you checked all your magnet plugs for signs of extra metal?

 

[MBurroughs]

Yeah, I've checked pretty much everything. I hate to sound dismissive as I do appreciate your input in any case.
The sound originates right between the transfer case and the transmission - which is why I presume it's the bearing in the AA adapter. I replaced the input gear on the transfer case as it walked on the shaft a tiny bit, and was a potential culprit.

 

[stevebradford]

I got nothing else... sounds like a tough one.

 

[Brandon Rains]

I got the same setup on a 89 FJ62, and I have the same problem. It's driving me nuts!! Did you ever seem to figure it out?

 

[morganism]

speedo wheel and cable?