M50D Weird Noise

[steveoelo]

Recently swapped my noisy fm132 with a m50d that the guy was unsure of the condition. Opened it up and everything inside looked brand new. Installing it, when putting the fluid in, I noticed metal shavings on the magnetic drain plug. Took it around the block and noticed that 3rd, 4th and 5th made noise but only at certain RPMs. For example anything above 2500rpm in 3rd makes no noise. Anyone know what it could be or am I just hearing engine noise? I figure if it's a bearing it will make noise at any speed in any gear expect 4th, but 4th seems the loudest. The noise kinda sounds like a grinding noise but every gear shifts smoothly. Thanks

 

[Shran]

Metallic goop on the drain plug is more or less normal... every manual trans I've drained has at least some on the plug, others have a lot. As long as there are no big chunks and/or the fluid isn't chunky or sludge, it's simply not an issue.

The noise could be and probably is a bearing. I'd just go with it and see if it gets any worse, you knew it was an uncertain deal going into it... nothing to lose now, really, unless you want to take it out and rebuild at this point. Bearings will last quite a while even with some wear as long as they have adequate lube.

 

[RangerFabWorks]

How was the pilot bearing when you put the new transmission in?

 

[steveoelo]

The entire clutch system was replaced and when in gear out of the truck, all the bearings seemed to feel like glass

 

[4x4junkie]

Is it like a metallic rattling noise?

If so, it could be a weld on one of the heat shields on your exhaust popped loose and is rattling.

 

[steveoelo]

Honestly this might sound stupid but the noise sounds like it's coming out of the shifter. It sounds more like a vibration than a grinding noise. It's pretty quiet but its just annoying to listen to

 

[BlackBII]

Sound will travel all the way through the drivetrain and up into the shifter.

Have you checked the u-joints on the driveshaft?

If it's 4 wheel drive check the transfer case output bearing. Those are notorious for vibration and noise.

 

[steveoelo]

2wd extended cab, did one of the u joints when I did the swap. I know my cat heat shields rattled but I wrapped them in mechanics wire real tight so I don't think they would rattle. The manifold heat shields seemed tight but not to sure how to check if they're not.

 

[steveoelo]

Update: talked to another mechanic and he thought it was the gears in the rear end not meshing probably. This got me thinking, before the trans swap, in 4th gear the truck had not vibration at all. The only 2 things that are now different are the transmission and drive shaft. Since it sounds like a vibration, is it possible I got a crappy drive shaft from the wreakers? It only makes the vibration at certain RPMs/speeds and only when your accelerating

 

[Shran]

It's totally possible, you could take the driveshaft into a shop and have it balanced and checked for wear or just get another shaft from the junkyard.

 

[Needles929]

Update: talked to another mechanic and he thought it was the gears in the rear end not meshing probably. This got me thinking, before the trans swap, in 4th gear the truck had not vibration at all. The only 2 things that are now different are the transmission and drive shaft. Since it sounds like a vibration, is it possible I got a crappy drive shaft from the wreakers? It only makes the vibration at certain RPMs/speeds and only when your accelerating

Following this. I have kind of wondered about a similar sound that I get also. Please update us with info when you figure it out.

I get a slight sound that seems to be more prominent in 4th as well. It almost sounds like a vacuum hiss coming straight from under the boot and console for the shifter. Fluid looked great and the magnetic plug had very little metal on it.

 

[Needles929]

Fixed!

Mine was the shifter being loose. Took off the plastic console and boot. Cleaned and tightened the shifter plate bolts (3 Torx)
Tightened also the bolt with the jam nut.

That was quite a bit of vibration noise from something so simple.

 

[steveoelo]

Right on! Mine ended up being the axle bearings

 

[Terry]

I saw a driveshaft balance vibration posting not to long ago. You can put one or a few hose clamps on the driveshaft. Drive is ara around then loosen up the clamp and rotate it. Do this until there is no more vibration.

Sent from my SAMSUNG-SM-G920A using Tapatalk