Birfield Going Bad? (1 Viewer)

[Groucho263]

Hey guys,
Need help troubleshooting the left front while in 4 wheel drive.
When in 2 wheel drive and hubs not locked, it drives and turns with no problems.
Hubs locked and in 4L, it goes forward and reverse no problem as long as the wheel is straight. Turn the wheel and get a clunking noise whether turning left or right, forward or reverse.
Hubs locked in 4H, same issue.
I have not tried 4L or 4H with the hubs not locked.

I did the disc conversion a couple years ago...did I mess something up in there? Is the Birfield going bad? I got the conversion kit from Georg...so don't think it came with new Birfields...so the old one might be bad? Did I just not add enough grease, etc.

Thanks...see videos.
Video 1

Video 2

 

[peesalot]

Is the front diff open or locked ? either way that noise is not right. Could be a hub gear not engaging properly or it could be a birf, is it specific to one side ?
I would open that side up, it is not that hard to take wheel off, pull & hang caliper , , disassemble, that way you can inspect, locking hub, hub bearings/seals, knuckles , etc..... but yeah, that noise would cause me to open her up.

 

[Groucho263]

Stock 1975 FJ40 differential. Yes, specific to the drivers side.
Ok, I was thinking you were going to say open it up. Once I pull/hang calipers...it's been a bit since I did the disc conversion...but would just disassemble and inspect.
One thing I did think I noted...it might just be in my head though...was when I was going through the process, sometimes the truck would slow to a stop like it would normally in 4L, and sometimes it kept moving...like the hub wasn't engaged. Is that possible?

 

[Jdc1]

Try this- you might not need to pull apart if it’s in the lockout.

 

[Groucho263]

@Jdc1 that's perfect. My old brain...I think I had an issue on install of that front left locking hub. I'll work on this and report back.

 

[Chungas Revenge]

Try this- you might not need to pull apart if it’s in the lockout.

Great vid…

 

[Groucho263]

@Jdc1 quick follow up. That video was awesome. Good news - I did install the hub incorrectly...I had the clutch spring incorrect.
Bad news - that didn't solve the problem.
The clunking in that video is still there and def doesn't sound right. Still isolated to the left front with the same troubleshooting steps as above.
Any thoughts from anybody? Bad birfs?

 

[Groucho263]

Bump. Any thoughts.

 

[DSRTRDR]

have you looked at the adjustment of your steering stops ? - tire rubbing may give a rhythmic sound [I call that "pseudo-birf" - mostly encountered in downhill steering on my 40]

adjusting the steering stop to keep the tire more inside might help

 

[Groucho263]

@DSRTRDR thanks for the post. The problem I have is a definite clunk in 4 low/high with the hubs locked. The left wheel makes a bad clunk if the wheels are turned at all...and it sounds like it's in the axle/knuckle. I don't have the problem in 2wd with the hubs unlocked.

 

[pb4ugo]

It seems you're going to have pull the birf and take a look. While you're taking thing apart look for problems with the lockout, loose wheel bearings and spindles and such. Look for wear or contact marks and slop. There's no way for us to diagnose your problem by looking at pictures and video's. The problem is in front of you. Once you get down to the birf put it in 4wd and twist the birf back and forth and try to get it to click. Afterwards pull the birf and look for slop. You may have to disassemble the birf. Make sure the knuckle pivots smoothly and has no up and down movement or wobble at the upper and lower trunnion bearings. Clean and inspect.

 

[70fj40]

^^^^^This
There is no other way. Check it just the way he said and you will find the problem. It likely is time for maintenance on those parts on both sides anyway.

 

[Groucho263]

Ok. Somehow I knew you guys were going to say this. Was kind of hoping for the magic wand. I’ll get to it this weekend and report back. Thank you guys.