FR birf spline sheared.. need tips

[itchy355]

Hi all!

After a long time there are first signs of my neglect to service. My front right birf cleaned the flange teeth and itself. Replacing as soon as possible. It happened in low gear backing off a slightly unfriendly driveway, about 15° incline, made it successfuly to the top (as many times before), then hit the breaks, and the second I've gone from R to D there was a big CLANK and then well you can imagine. My error (which I didn't know then) was I removed the driveshaft but not the flanges, which probably destroyed the right birf. My fault. Didn't know I can drive with the flanges off and just duct tape over it..

Now. I'm a beginner self-serviceman (yes, probably the worst combination)) and so I'm doing many mistakes wrenching. It's also my first 4x4 soo yeah.

I've been told this should not happen just out of the blue like this -- no ,,wheels in the air running at high speed suddenly hitting tarmac'' kind of situation. Everything was slow and easy. I don't even drive her off road. They (more car-savvy friends) tell it's probably some axial play in the driveline that makes the flanges take abuse everytime I go from R to D etc. I also do a lot of engine braking, like on every red light, if that's any clue. Also ever since I've had this truck it sometimes goes ,,clunk'' when I stop, sometimes worse sometimes not. Also changed the brake pads while there and front left side is unevenly worn - the outer pad was almost gone, inner pad was yet quite OK, right side was evenly worn out (maybe slightly less than left side), changed all of course.

Would you be so kind and give me some tips where to look? My personal guess is probably the driveshaft spiders, maybe the spider rings in the diff, anything else? I'm scared not to induce any more trouble.
My plan for now:
- drive very very carefully now with the botchered flange on (locked center)
- ordered used drive flanges, they look fine
- will order the birf
- will reseal the FR axle, change all bearings
- shall I change the spindle bushing? If it's a home-possible job

Side note: I've successfully resealed the FL side 2 years back, didn't have time yet for the right side (which is now leaking very very badly and when I'd dumped the diff oil to check if it's got teeth in it, it was very low level, luckily only shavings but still). Refilled the grease in the front and rear shaft 2 years back too, but it's everything just ongoing guess work for me - I definitely don't have the ,,eye'' for any over-the-limit axial plays.

 

[BILT4ME]

What year truck?
How many miles?
Are you SURE you didn't shell the ring and pinion? These are known to be weak in reverse, and if you've done this a number of times, this may have been the one.

Do NOT throw away your "bad" drive flange.

If I had two, I would carry them in the truck so if I broke a front (or rear) axle and needed to cap the hubs, then lock the CDL, I could do it without trying to use duct tape. I would also grind out the inside so it's nice and smooth so there's no chance of binding on anything. Remove the DS and nothing internally will rotate.

 

[itchy355]

Sorry.
93 1HD-T full time auto with a cdl switch. Full lockers although the front and rear are non-functional. Bone stock. 215k-ish miles. Maybe more, it's a sort of complicated build

Thanks!

Well. I am of course not sure I didn't f...ck up the diff .. how to check? One clue, when I engine-braked after this incident, noticed the left front wheel a wee bit skidding, so I guess the diff is working. Fully agree with keeping the flange, yup!

So in general; what's the correct way to drive up a rather steep driveway and then go off? Reverse up the hill in low, hit brakes, put AT to neutral, release brakes to let go off any wind up, put high range and then go Drive? Also one bad thing about my driveway is it's grass from bottom to top, but then of course starts tarmac, so the rear end of the car is on tarmac when I get up.. am thinking of doing the cdl switch mod to disable automatic CDL engage when in low range. I definitely don't need locker to get up.. also is it better not to engine-brake in a full time 4wd? IDK but if that was a factor too, I'd much happier change the pads twice as often than to change birfs. Ordered it now, cost me about USD 180

 

[BILT4ME]

Sorry.
93 1HD-T full time auto with a cdl switch. Full lockers although the front and rear are non-functional. Bone stock. 215k-ish miles. Maybe more, it's a sort of complicated build

Thanks!

Well. I am of course not sure I didn't f...ck up the diff .. how to check? One clue, when I engine-braked after this incident, noticed the left front wheel a wee bit skidding, so I guess the diff is working. Fully agree with keeping the flange, yup!

So in general; what's the correct way to drive up a rather steep driveway and then go off? Reverse up the hill in low, hit brakes, put AT to neutral, release brakes to let go off any wind up, put high range and then go Drive? Also one bad thing about my driveway is it's grass from bottom to top, but then of course starts tarmac, so the rear end of the car is on tarmac when I get up.. am thinking of doing the cdl switch mod to disable automatic CDL engage when in low range. I definitely don't need locker to get up.. also is it better not to engine-brake in a full time 4wd? IDK but if that was a factor too, I'd much happier change the pads twice as often than to change birfs. Ordered it now, cost me about USD 180

If the LF wheel is skidding, then the diff is working and neither flange is stripped.

Typically it's the R&P that break when reversing. The pinion takes a chunk out of the teeth on the ring, so the spiders stay intact and the diff part still works. One guy here was pulling out a shrubbery in reverse when he blew his front R&P. This was a small shrubbery.

You may want to drain the fluid and run a magnet around inside to see if you can find chips before they get pumped to the pinion bearing and the whole thing s***s the bed.

I would raise the front axle off the ground, leave the CDL off, chock the rear wheels. You may have to place the TC in neutral, I'm not sure.
Turn the front DS by hand to see if you feel a rough area as the R&P travel around in there.

Then turn each wheel independently and see if the opposite wheel turns the opposite direction or the DS turns or what and feel for crunchy stuff.

You can still pull your drive flanges to check them. There should be a fair amount of shaving in the cap and hub I would think if it decided to go.

If I am backing up a steep driveway, I will do it in LOW range, CDL UNLOCKED (unless I'm on grass / dirt and I NEED the traction). This gives me the most torque and control backing up and the least stress on the diff because the CDL is unlocked. I did the pin 7 mod on mine to allow it to be locked / unlocked in high or low, depending on what I need. If you have not done this, then you NEED to. Search for it here, you will find a number of threads, but one shows it in detail.

 

[itchy355]

Well I know for sure the flange is **, I have it in my hand .. the left one is intact. The exact process was following:

1; Drive in R; stop; change to D => CLANK gaaawd whazzup!
2; handbrake, D, get below the truck, see rotating front end, facepalms, swearing
3; call friend, says it's probably the front diff. Q - can I drive with CDL and front shaft off? A - probably yes, anything that's f..cked up is f..cked up anyway, just disconnect the DS, lock it.
4; drove some 100km, weird grinding sound half the time (now I know this was the flange & birf getting their teeth off whenever the front diff ,,decided'' to turn from the left tyre or not)
5; started prepping to take off the axles, because I thought it was the diff. Started unluckily with the left one, took out the axle, started to rain so stopped
6; actually checking mud for any clues and guess what, first what came up is ,,check your drive flange''
7; after the rain I checked the right flange and there we go.
8; replacing the left axle & driveshaft, because it's better to drive with everything in place in this situation, as the right flange doesn't grind anymore (the axle shaft is rotating more or less consistently with the wheel being pushed by tarmac).

Now IF I'd checked both the front flanges immediately after the incident (lesson number 1), I maybe wouldn't destroy the birf. Oh well. I also could save myself of the useless work on my left axle, but at least I checked my previous left axle job and everything looks fine..

Okay, definitely adding the 7 pin mod to my list.

The front left wheel really skidded and the right flange is really shot, skidded just a tiny bit but I noticed. Stopped engine braking since that.. not sure if I will do it again after I fix the thing :{. I think it skidded because of the CDL .. and some magic? Or you reckon there really might be a stripped tooth that in that very moment just got caught into the gearing... gawk

 

[BILT4ME]

Well I know for sure the flange is **, I have it in my hand .. the left one is intact. The exact process was following:

1; Drive in R; stop; change to D => CLANK gaaawd whazzup!
2; handbrake, D, get below the truck, see rotating front end, facepalms, swearing
3; call friend, says it's probably the front diff. Q - can I drive with CDL and front shaft off? A - probably yes, anything that's f..cked up is f..cked up anyway, just disconnect the DS, lock it.
4; drove some 100km, weird grinding sound half the time (now I know this was the flange & birf getting their teeth off whenever the front diff ,,decided'' to turn from the left tyre or not)
5; started prepping to take off the axles, because I thought it was the diff. Started unluckily with the left one, took out the axle, started to rain so stopped
6; actually checking mud for any clues and guess what, first what came up is ,,check your drive flange''
7; after the rain I checked the right flange and there we go.
8; replacing the left axle & driveshaft, because it's better to drive with everything in place in this situation, as the right flange doesn't grind anymore (the axle shaft is rotating more or less consistently with the wheel being pushed by tarmac).

Now IF I'd checked both the front flanges immediately after the incident (lesson number 1), I maybe wouldn't destroy the birf. Oh well. I also could save myself of the useless work on my left axle, but at least I checked my previous left axle job and everything looks fine..

Okay, definitely adding the 7 pin mod to my list.

The front left wheel really skidded and the right flange is really shot, skidded just a tiny bit but I noticed. Stopped engine braking since that.. not sure if I will do it again after I fix the thing :{. I think it skidded because of the CDL .. and some magic? Or you reckon there really might be a stripped tooth that in that very moment just got caught into the gearing... gawk

Don't drive it with only ONE bad drive flange. It will overheat the spiders inside because the wheel will push and rotate the axle, but the other side has to "catch up" and that's due to friction internally which causes heat. Disconnect BOTH sides if one bad drive flange and remove the DS.

With that confirmed evidence of a bad drive flange, I think you're good on the R&P. That was the "fuse" that let go. This time. Now with new ones, you've moved the weakest link.

Make sure you clean and repack your wheel bearings due to the drive flange debris getting into the bearings.

Did it actually destroy the birf?

I don;t have a clean explanation of why the LF wheel would skid during engine braking if the RF drive flange was "sheared". This should have relieved all bind on the front drive line. Unless it was due to braking (with the brakes) because there was no differential or drive line resistance to keep it pushing forward or to equalize, essentially doing "driveline braking".

Driveline braking can be done if you lock the CDL and apply the parking brake (only in the rear) and it will also create the resistance through the driveline and "brake" the front wheels due to the driveline being restricted from turning. If the CDL is not locked, the CD will allow the front axle to turn independently from the rear.

On these trucks, with the CDL unlocked, you can place ONE tire on a slick surface or lift it off the ground and you will go nowhere. The viscous coupler (VC) will assist if you give it enough throttle, but with an HDJ, I don't think you have a VC.

 

[itchy355]

Posting pictures. Gah! Seems like my knowledge & logic is even worse, I thought that 1 bad flange & CDL might be fine. I did notice unusual heat on the axle when I touched that.. just didn't think it was anything serious. So just to check; IF I had a working front locker, it would be fine to drive with locked front, center and one working and one botchered flange, right? Darn. Just a note I'm pretty sure that there's a VC because the truck sort of moved even in non-locked mode, although with horrible sounds (coming from the flange).

Current state of the birf after some cleaning:

I think it's pretty shot, it might work for a while but still. The splines are pretty pointy.

Now; the moment I got what's happened, I've quickly ordered used flanges which were cheap and fast, and have them in my hands now. One of them is ,,better'' (it's got some nice flat areas on the splines), one of em is ,,worse'' (it's pretty much as pointy as the current birf but it might still work a while); now thinking. Might it be an option to use either of them now, so I can drive the truck without any bigger issues? Of course no low range, no crawling etc. I just need to pull a small trailer with dirt. The birf is ordered and should come next week, so I would properly fix the thing ASAP then. Thinking I'd use the ,,worse'' flange on this birf, then replace it with the ,,better'' one after I get the new birf.

BTW I'm gonna do the whole FR axle including all the seals and trunnion and wheel bearings anyway. Just waiting for the new birf..

My ,,good'' ,,new'' flange

..and my ,,worse'' ,,new'' flange

And thanks for your patience! I'm really trying to learn the logic to NOT get myself into this kind of trouble next time

 

[BILT4ME]

Posting pictures. Gah! Seems like my knowledge & logic is even worse, I thought that 1 bad flange & CDL might be fine. I did notice unusual heat on the axle when I touched that.. just didn't think it was anything serious. So just to check; IF I had a working front locker, it would be fine to drive with locked front, center and one working and one botchered flange, right? Darn. Just a note I'm pretty sure that there's a VC because the truck sort of moved even in non-locked mode, although with horrible sounds (coming from the flange).

Current state of the birf after some cleaning:
View attachment 2409419

I think it's pretty shot, it might work for a while but still. The splines are pretty pointy.

Now; the moment I got what's happened, I've quickly ordered used flanges which were cheap and fast, and have them in my hands now. One of them is ,,better'' (it's got some nice flat areas on the splines), one of em is ,,worse'' (it's pretty much as pointy as the current birf but it might still work a while); now thinking. Might it be an option to use either of them now, so I can drive the truck without any bigger issues? Of course no low range, no crawling etc. I just need to pull a small trailer with dirt. The birf is ordered and should come next week, so I would properly fix the thing ASAP then. Thinking I'd use the ,,worse'' flange on this birf, then replace it with the ,,better'' one after I get the new birf.

BTW I'm gonna do the whole FR axle including all the seals and trunnion and wheel bearings anyway. Just waiting for the new birf..

My ,,good'' ,,new'' flangeView attachment 2409434

..and my ,,worse'' ,,new'' flange
View attachment 2409435

And thanks for your patience! I'm really trying to learn the logic to NOT get myself into this kind of trouble next time

OK, looking at the "new" drive flanges (DF from here on out...)
The worn DF needs to be placed on the LEFT side since the RIGHT axle is the one that ate the old DF. Because, if you look at it, the worn DF is obviously from the right side of the previous truck based on the wear pattern. You want it so the better splines are on the worse axle.

Yes, that birf needs replaced.

With the front DS off, you can use low range. Doesn't hurt anything. Just keep the CDL locked. Without the Pin 7 mod, you may have to lock the CDL by placing the tcase in low to lock the CDL. Shut off the truck. Pull the CDL fuse. Start up and drive.

Yes, if your front locker was working, you could have locked it and still have 3 wheel drive. Then the RF birf and axle would have rotated "together" but not as much "chewing" would have gone on.

These are known that the RF DF are the ones to go first under "normal" use. Has something to do with physics of short shaft VS long shaft that's out of my league of understanding.

Don't forget to lock your differential before you pull your axle shafts.

With the look of all that, you probably need all new axles.

Get with Cruiser Outfitters to get a kit and possibly replacement axles with birfs. @cruiseroutfit Kurt and his folks are GREAT people and their prices are competitive.

 

[itchy355]

Oh I'm in Europe but thanks..

So the plan is to leave DS on, put the better flange on the right side and drive carefully until I get to replace my birf & everything else, which should be soon enough. I'm looking at about another 100 miles before I replace the birf and be done with it.

 

[BILT4ME]

Oh I'm in Europe but thanks..

So the plan is to leave DS on, put the better flange on the right side and drive carefully until I get to replace my birf & everything else, which should be soon enough. I'm looking at about another 100 miles before I replace the birf and be done with it.

Cruiser Outfitters ships internationally.........