I have had my moser 12 bolt installed for about 8 weeks. A few days ago, the transmission let go. I was driving and BOOM, the output shaft area blew out and cracked the housing losing all my fluid.

The tranny shop was stumped why this happened. They did find out the source of the problem. The distance between the moser 12 bolt rear end and the transmission is less than the distance between the stock axle and tranny.

What does this mean? Well, the stock driveshaft or stock lenght shaft is too long. It put too much stress on the output shaft and caused it to fail. They are cutting down the driveshaft for a custom fit. Moser was not helpful nor wanted to admit this to me on the phone. NO WHERE DID MOSER MENTION THIS SMALL OVERSIGHT. THE DRIVESHAFT NEEDS TO BE SHORTENED or else. Some of you might already know about this but I thought I would inform my peers on this board of the problem. I hate to see anyone have to go through a similar 2000 tranny/driveshaft job after dumping 2,300 in a new rear end

 

thanks for the heads up!
too bad i dont own one

 

This thread reminded me another I read once about the Moser.

http://www.ws6zxr.com/showthread.php...ighlight=moser

It mentioned the shortened DS problem with the Moser yoke.

 

It's probably worth posting this as a heads up, but it's pretty well known. You should always check the driveshaft for proper length when installing a new rear end. The idfference is between 1/2 and 3/4" if I remember right.

Rich Krause

 

Damn, too bad I do. . . That makes sense, I always had that thought in the back of my mind, but wasn't sure. . . Did your machine shop say what length their making the drive shaft now? I would like to know, thanks!

 

I checked mine and shortened it first. Sorry for you problem, ouch...

I would normally view that as something the installer would check for for any rear installation. When the car is up in the air it looks fine, but when weight is put on the tires, everything shortens up. Also, under heavy load the distance becomes a little shorter too. Happens in all rear wheel drive vehicles and is something I would expect a qualified mechanic to be aware of. Not knocking your guy, but checking driveshaft length is a pretty basic thing.

 

These guys are right.. that's something that should always be checked.

Of course, not knocking you like Ted mentioned.. everyone has to learn, and if you aren't told & don't notice.. well, you'll learn one way or another

Good luck with it

 

Yes unfortunately it was an expensive lesson to learn. I am glad to see everyone else was smart enough to check this first

I did not have the luxury of a lift so it was a little bit harder to check for me. BTW here is a response from Moser from email.


"We do not mention it because I do not know of anyone else who has had to
shorten the driveshaft. Generally all you have to do is change the u-joint
to adapt to the 12 Bolt to the stock driveshaft and that is all there is to
it. Something else in your application must have changed if the driveshaft
was too long.

Thank you,

Moser Engineering"

 

Thats why I rarely every call or email tech supports.....most of them dont know what they are talking about.

I have a local mechanic here in town that I trust and thats who I consult. ......and of corase the collective mind of CZ28 never has let me down.

Sorry you had to learn the hard way.

 

...I just bought one of their (moser) driveshafts when I installed mine. It worked perfect. I did this because they (MOSER) told me that mine would be too long without modification. I figrued I would just buy theirs insted of messing with mine. Apparently one or two people there know whats going on...but the new guys must not. Hope you get it working.

 

I've heard of Moser accepting no responisbility in this matter before. Its funny that they still haven't posted this on their site or even included it in the info package they send with it.

Does anyone know if this is the case with teh Moser 9" as well?

 

Well, to an extent it's really not their responsiblity, IMHO. If they tell you that it will fit and you base your purchase decision on their advice, I suppose you have a point. In that case, maybe selling you a driveshaft at cost would be good customer relations.

Still, they ought to get a clue.

Rich Krause

 

I do hold them somewhat responsible. All they had to do is say "The stock driveshaft may need to be shortened" They do talk about the panhard bar deal where you need to notch but no mention of this driveshaft problem.

I will find out today how much I had to shorten mine and post it

FYI - That email I posted from Moser was replied by Rob Moser himself!

 

We shortened the front yoke on my stock driveshaft by about 1-1/2". If not, it would jam into the transmission under a hard launch or on large bumps(RR tracks).

 

I too had the loud bang when going over bumps. I wasnt sure what it was at first. Almost felt like I was bottoming out but now I know it was the driveshaft banging the tranny