Topic: T-Case Help! I am stumped. Success!!!

[Slolyfe]

21 spline dual cases 4.7 in the rear. Twin sticks. Everything worked great for last 5 years.

Broke a rear output. Put in a longfield chromoly. Whenever I tighten the flange nut on the output, the 4wd stick will not shift. If i loosen the nut slightly it shifts fine.

Tried to drive it to see if it was just sticky still wont disengage. Stuck in 4wd. the second I loosen that nut it shifts perfect.

[Cheesemaker]

Are they the same dimensions?   

[Slolyfe [OP]]

Are they the same dimensions?   

Yes. Made to be a direct replacement. Bobby even explained that he designed them stock so if it broke on the trail you could throw your stocker back in.

Literally the difference between shifting and not shifting at all is torquing the nut.

[85runner_]

Did you reuse or replace the rear output bearing? Tightening the nut may pull on the output just enough binding the shift forks/rails

[Slolyfe [OP]]

Tightening the nut may pull on the output just enough binding the shift forks/rails

Something like this must be happening. But literally a half turn of the flange nut makes it work/not work.

Yes I reused the rear output bearing. On a visual inspection it looked fine. not damaged, loose, and spun fine.

[Jud]

Did you put ALL the pieces on there? it's as simple as putting one little thing on in the wrong order that could screw you. Oh yea, COME TO MOONROCKS SEPT. 7-9!!!

[Slolyfe [OP]]

Did you put ALL the pieces on there? it's as simple as putting one little thing on in the wrong order that could screw you. Oh yea, COME TO MOONROCKS SEPT. 7-9!!!

Don't think I can make that. Stuck working.

Pretty sure I did. Didn't have any leftover pieces, followed the marlin crawler 4.7 install directions the first time and the FSM the second.

[Jud]

Call in sick, Let all the tweaker huts in Oakland burn to the ground!!!

[fordh8r]

I have a set of 4.7's that I'm gonna be putting in sometime. I only wish I had done it recently so I could have a fresh visual on the arrangement of parts inside there. 

[Slolyfe [OP]]

It's pretty simple in there. I'm thinking I tweaked something when I snapped the out put.

Calling bobby long tomorrow. Guy at marlin couldn't help.

[BigMike]

Loose the flange nut, engage 4WD, then tighten the nut. If you are then able to shift into 2WD, back to 4WD, back to 2WD, et cetera, without trouble then it's possible the step on the output shaft that the 4WD clutch hub rests up against is machined too deep and/or the clutch hub is was not machined correctly and is allowing the clutch hub to preload the front output drive gear.

This has got to be a very unlikely scenario...

Regardless, if it does end up being a flaw in the output shaft, Bobby has great customer service and he'll get ya a replacement part in no time

BigMike

[fordh8r]

Does everything spin ok with the nut torqued? Just the shifting is affected?

[BigMike]

I'm thinking I tweaked something when I snapped the out put.

I'd think that any damaged parts would be evident during assembly. (either visually or by interference)

This has got to be a very unlikely scenario...

Calling Bobby is the best bet of course, but if you have time and are bored, try this to check my theory:

Remove all the parts and then assemble the new Output shaft on your bench, just as you would in the t/case, and then torque down the flange nut and see what component(s) are binding up. The output can easily be assembled without the housings. Just put all the pieces together in the proper order, and you'll be able to see everything first-hand and can slowly rotate components while tightening the flange nut to see where along the line of parts is the binding occurring.

If it was something like a bent shift fork or a damaged shift hub, then tightening the flange nut should not affect the shifting performance (or lack thereof) of these components since they are not mounted or pressed to (ie. they float about) the components of the output shaft.

If it ends up being some bad t/case parts not related to Bobby's shaft, let us know. We've got many good core t/case parts that we can send your way on Monday

Good luck man!!
BigMike

[Slolyfe [OP]]

Thanks guys.

I can loosen the flange nut and shift from 2wd to 4wd. Tighten the nut and it wont shift. Loosen the nut and shift from 4wd to 2wd. Tighten the nut, stuck again.

Everything spins effortlessly and correctly in 2wd and 4wd. Just can't get from one to the other without loosening the nut.

[BigMike]

Okay,

How about this: When the Longfield output first came out they suffered from poor tolerance control. For instance the low speed cage bearing race would have different measurements on different shafts. They seemed to have fixed this years ago but it does leave the question open in my mind if the 4WD clutch hub splines are not machined correctly.

For instance, if the splines are not concentric with the shaft, when the clutch hub is ramped and preloaded on the output splines from the tightening of the flange nut, it would be forced offset from the shift teeth of the low speed gear causing A) the shift collar to bind if in 4WD (can't disengage 4WD) or B) shift collar to low speed gear shift teeth interference (can't engage 4WD).

If you have a good, used stock output shaft then I'd throw it in there to figure out if it is the Longfield component or damage to your case components. That would eliminate all doubt surrounding the Longfield shaft

BigMike

[Slolyfe [OP]]

I like your thinking. Something like offset splines would make perfect sense. When that flange nut is not tight, but the tailhousing is, wouldn't that hold the shaft centered? ie once the tail housing was on it wouldn't shift either?

 Still waiting to hear from bobby if this has been a problem on the past.

I don't have an old output shaft other than the blown up one. I'm just crossing my fingers he has had this problem before.

[BigMike]

The tail housing does hold the smaller bearing in place in reference to the other housings, however, 1) this is a conrad roller bearing which itself has free play, and 2) tightening of the flange nut is inconsequential to the placement of the tail housing. Unless the tail housing was deformed so badly that you can barely pass the flange past the output seal without great force, the mere tightening of the flange nut won't affect the housing's control of the shift collar to output shaft positioning.



I'm throwing this stuff around, but really it could be anything. Maybe multiple parts really did get messed up

Keep this thread updated. We can send you a stock shaft next week to isolate the issue more. While you are waiting, try my advice above to assembly the components of the output shaft outside of the transfer case. Lay everything down on your work bench and then assemble just the output shaft including the flange and flange nut. Be sure to include the shift collar (shift fork isn't needed) and slide the shift collar 4WD-to-2WD back and forth while you slowly tighten the flange nut. I think with everything out in the open and visible you'd be able to see what is interfering.

If it works outside the transfer case, good, it's not Bobby's shaft Then you can look at maybe a bent shift fork or rail, or worse deformed housing(s).

BigMike

[Slolyfe [OP]]

Sounds good. Ill let you know what's going on. Thanks for all the advice.

Austin

[Slolyfe [OP]]

Bobby called me back today. He is overnighting me an output. He measured a few Of his and said they were off by a few mics but within tolerance. I'll let you all know cause I know your on the edge of your seat.

Also going to try big mikes idea of assembling them out of the housing. But am pretty busy right now.

[Goldrush]

Ya man, I really do want to hear what this issue was. Please keep us updated! Thanks!

[Slolyfe [OP]]

So it looks like there is a machining error in the distance on the first step. When the flange nut is tightened it is pinning the clutch hub to the 4wd transfer drive gear not allowing the 2 to spin independently of each other. Thus if they are not perfectly aligned when the nut is tightened you can't shift.

The stock gap is 4.09 and the Longfield gap is 4.55. Bobby overnighted one to me that he machined so we will see on wed.

[Slolyfe [OP]]

Here is where it is binding.

[BigMike]

Wow great photos and thanks for the updated! It's great to know you've ordered from a reputable company who takes care of their customers!!

That's why people should order from companies who 1) have been in the business since the beginning so that they 2) care about the customer because 3) they are here out of innovation and love for the sport!!

Ya better get that replacement sucka in there before the Round Up!

[Slolyfe [OP]]

It will be ready for the round up! still have to french in the rear leaf hangers and new axle perches.

Been on the phone with bobby about 5 times yesterday and today. He has been very helpful, but wouldnt have figured it out with your advice of putting it together outside the case! Thanks again.

Austin

[Slolyfe [OP]]

So bobby machined .3 of a mm off the second output step(where the thrust washer and transfer drive gear seat). When I installed the new output still had the same problem.

[Slolyfe [OP]]

After trouble shooting on the phone with him, I ended up taking another .4 of a mm off the thrust washer which allowed the gear to release. So we are back in action! Thanks for all the help.

Austin.

[Jud]

Nice beer coozie fool

[OOPS]

Nice beer coozie fool

Glad you got it fixed!!!!!

In the old days when I still drank I used to tell people, "if you need a coozie, you are not drinking fast enough"!!!!!

[Cheesemaker]

Beer coozies are only for keeping the second beer cold while your drinking the first one!!