Flygtenstein

Coupler leaks. Right through the middle. First mine crapped the seal, now mine leaks through. Common enough on the auto's, only two don't.

The coupler is the same auto to 5 spd on late model stuff. The auto causes problems because of higher pressure, thinner fluid and being right near a jet.

I am not putting as many miles on the truck anymore, so I don't really give a darn about it. It leaks, keep an eye on it.

I have not read all the ways suggested, but Marlin has, supposedly, tried them all. Machining limitations prevent a pure billet piece, not to mention you need to get something down in there to push on the shaft to get it out.

My cheap advice? Stop calling Marlin, they are frying bigger fish. This problem is only a problem for maybe 25 people, and that could be off. It will get fixed when it is fixed. Get one with JB Weld and run it. This is a pretty minor part of a huge project.

At Marlin, talk to Dave. You will never, or almost never get to Marlin and Dave is as good as it gets.

Praufet

Hey why not cut the couple in half and weld it back together with a disc in between the two pieces? You'd have to make a spacer it increase the width of the adapter plate most likely, but is should work.
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weld there

Not sure how good you are with Al mike but your new welder sure looks like it is up to the task.

firemedic

I'm not a welder, but I imagine since all the power from the engine goes through that one piece, they wouldn't want to subject a weld to that kind of force, it would also have to be a perfectly lined up, and balanced/centered finished piece, probably tough to do...

Praufet

true, but not impossible, just throwing ideas out there. Still don't see why you can just cnc it.

dlbrunner

How close does the output shaft and input come where the coupler joins them? The machined piece sounds good, but if the input and output shafts are almost touching then the ends may need to be lopped off a little 1/32" or so to allow the barrier to be in place

mt_goat

Yeah I'm guessing that the coupler is made of hardened/ heat treated steel and welding would destroy those properties. Plus as someone said, you need to be able to use a puller to get it off the shaft so you wouldn't want the center to be blocked with solid steel.

bamachem

Cebby, SS3, Cheese, etc:

This may be a uneducated question, but why not just use some Permatex FIPG on the splines of both sides before you install the coupler? Once the FIPG sets, it should be durable enough to last, and would be just enough of a seal between the two to prevent the fluid loss AND it would flex w/ the thermal expansion/contraction. It would have a good 2-inches of surface to adhere to and should be fine for holding under pressure. Not only that, but it would seal it but wouldn't be permanent so the coupler would still be removable...

It might be worth a try anyway.

Cebby

Well, Marlin is sending his Epoxied version to me that supposedly solves the problem. I'm curious to see how they did it. So far, I think Andy's solution might be the easiest to try if it comes to that.

That sucker is definitely hardened steel. I'm not sure how something like this is made. I don't think they are CNC'd only because it would be difficult to get a tool down inside this thing to cut the grooves. The inside dia is only like 1 1/4 or so.

They told me like a week for the coupler to get done - I've been trying to get through today to see if they can send everything else now so I can build the case assembly sooner.

mt_goat

As I understand it, that was the first thing Marlin tried and it failed for some reason.

Robinhood150

To make the splines of the coupler they probably use a broach. Basically, it's the male side of the coupler made out of hardened tool steel and they force it through the steel which carves/scrapes out the teeth of the splines. Here's something I googled: http://www.usbroach.net/default_files/broaching.htm

To use a broach, it would need to protrude all the way through the coupler.

As for the permatex failing, I'd bet the torque mashes it all up even though the tolerances are close.

Cebby

Steve - I'd love to see a picture of this method in action. Sounds pretty cool.

Robinhood150

Here's another:
http://its.foxvalleytech.com/MachSho...roachingIS.htm

I couldn't find any pictures of the process itself. Broaching is also how they cut gears.

You might be able to braze or solder a barrier in there, but if you'd have to find a solder that will wet to steel or a braze material with a low enough melting temp to not destroy the heat treat of the coupler.

Robinhood150

My friend had this idea of using a rubber high bounce ball jammed in there...or alternatively, get a piece of rubber or better yet a thick piece of silicon gasket material (1/4"?) with a hole in the center. Put a bolt through the hole and a washer on each side. Tighten the bolt and the silicon will expand, sealing the tube. The only thing is we don't know if there's enough room for the bolt.

Cebby

I guess we all have our own theories...

I was thinking of hydrocutting (oversize) the same profile as the void in the coupler out of thick silicon material or something with a lower durometer measurement - slightly thicker than the space between the two outputs, then force it down into the coupler. When assembling the case, by bolting the two halves together, the outputs would squeeze the material tightening the seal. Not sure if that would be hard on the bearings though...

Cebby

One more question - are twin sticks a worthwhile investment for a rig that doesn't see a lot of rocks (ie AZ,CO, CA type wheeling) and mostly East Coast terrain?

FROR has them for $150 currently - Marlins are $199. Not sure I even need that. I guess I can add it later.

Any thoughts on this?

Cebby

Thanks for the link. That's pretty cool.

My stuff is going out today with the exception of the coupler.

dlbrunner

Probably easier to put the twin stick on before the final fitting. From experience messing with linkages while the trans/transfer is in place is a pain. One vote for twin stick, not for any specific reason, but "just because". My Cj3a had twin stick transfer and it was cool to have 2 low for moving a heavy trailer around.

sschaefer3

I don't have a twin stick, it would not fit in my cup holder. For 2WD low all I have to do is hit the front case down.

Twin stick is cool, but certainly not necessary.

Cebby

I'm not convinced I would ever need it. That being said, I can think plenty of other things to with the money.

Thanks for the input guys.

Cebby

A little more progress today and some comparisons...

6 bolts to remove the VZ bellhousing from the A340F. (the ones around the perimeter - the 4 uppers take a 14mm socket, the 2 lower take a 17mm)



Unbolt the kickdown cable (10mm socket):



Off she comes...



A shot of the A340F without the bellhousing: