Topic: Odd noise...Tranny?

[germ]

Thanks in advance for any input....

Here's the story...85 $runner, dual cases, 5 spd.

Last week, going down a hill in 4-low, felt/heard a "pop", then heard a metalic noise coming from the tranny/T-case area. I've heard the noise the last few times I drove it, only when down-shifting. Now it seems to make the noise all the time, but only when the clutch is out. When I press in the clutch, the noise slowly goes away. I've played with the tranny, crawler box and T-case, and switching between gear-sets doesn't seem to change the noise. I have noted the shifter lever on the crawl box seems to get pretty hot while driving on pavement. It's noticeably warmer than the tranny or T-case, but the T-case shifter gets pretty warm as well. There is no slippage in the clutch, and the tranny shifts normal. Crawler box and T-case shift without any problems as well.

I'm wondering if maybe the syncros finally died, or if maybe one of the bearings is having chest pain and about to die.

Any thoughts?

[Plekto]

Metallic noises from the gearbox means you're going to have to pull it apart or get a rebuilt one.  Sorry.  Different but similar thing happened to me a week ago.  Once you hear bearings going or things grinding, it's a lost cause.(and fixed sooner, the core's worth more and/or loads easier to fix than if it cannonballs or seizes)

[79coyotefrg]

Germ,  how long have you had the dual case??  is it a  MC05 ??  if its a MC05  you need to call Marlin, chances are  the  adapter bearing is  gone

[Willy Mammoth]

Drain the oil in each box and see which one comes out with metal in it. That will at least point you in the right direction.

[germ [OP]]

is it a  MC05 ??  if its a MC05  you need to call Marlin, chances are  the  adapter bearing is  gone

Thanks Glen, I was thinking the same thing. Kinda sounds like a chain on a sproket (like at the amusement park), only higher pitch and faster. Does change frequency with increased RPM. That to me suggests a bearing, but my experience with bearings is that they tend to genade, and not just die slowly. To be honest, I'm not sure if I have the MC05 or not. Is there an easy way to tell?

Drain the oil in each box and see which one comes out with metal in it. That will at least point you in the right direction.

Dang Mark, your always so sensible. Of course that means I actually have to get out and do it, which is a whole lot more work that having you guys help me figure it out! I suppose it's really what I need to do though.

[79coyotefrg]

Germ,  get under there and look for your  adapter number,  they all have a number on them,  mine is 2919,  stamped on the bottom of the adapter,  then call the shop,  they can tell you if its a MC05 or MC07

[germ [OP]]

Thanks Glen, I'll do that!

Erik