Which Alternator

[Randomrunner12]

Hey yall,

Anyone had to replace the Alternator on the 10-12 4th gen truck? Yesterday i started to notice this low whirring sound when i started the truck. Only heard from inside the Cab and under light throttle in neutral. Seems to go away as the day warms up or the truck is warm.

Checked power steering pump for leaks and fluid. it was all good and it doesnt make the typical sounds like a pump would when low or going out and needing replaced.

Tested batteries and Alternator at Autozone and O'reillys and they all tested good both times. I am wondering if maybe it is the bearing for the alt pulley? Already replaced the Tensior and idler earlier this year with a Geno's Garage replacement and the gates belt as well. Alt has 188k miles on it and is factory.

Which alternator did yall end up going with when replaced and from where? I see the Mean green unit on XDP for 380$ and says that it has up to 340% better charging. NO exp with this brand so not sure on it.

 

[Ozymandias]

Didn't read to much good about the MG quality.

 

[nukegm]

comrade - all i can say is EVERY electrical part i have bought at orielley and the zone is JUNK. most all of them failed in weeks. on mostly fords and subarus - alternators and starters specifically. however, there is a place in boulder co, where an older guy rebuilds starters and alternators one at a time. i have a 70 bronco, where his starter is still going at 300,000 miles. and an alternator close to that on a different vehicle. i cannot comprehend how the chain auto stores stay in business given their garbage rebuilds. cheers!

 

[Randomrunner12]

Thanks guys for all the input. The noise I hear is at startup when it's really cold out. Goes away as the day warms up or the truck has been driven. No visual signs that the alternator might be failing other than the 12v connector I have shows battery voltage on it and it fluctuates from 13.8-14.2 while driving. No flickering lights or dash, no battery light either. Had all tested and everything is good and in working order.

Only thing I can think is maybe it's the power steering pump but it doesn't change noises when steering. Oil smells a little burnt so it's getting a flush on Monday. I haven't checked the pulleys with the belt off but the tensioner feels tight.

 

[nukegm]

Thanks guys for all the input. The noise I hear is at startup when it's really cold out. Goes away as the day warms up or the truck has been driven. No visual signs that the alternator might be failing other than the 12v connector I have shows battery voltage on it and it fluctuates from 13.8-14.2 while driving. No flickering lights or dash, no battery light either. Had all tested and everything is good and in working order.

Only thing I can think is maybe it's the power steering pump but it doesn't change noises when steering. Oil smells a little burnt so it's getting a flush on Monday. I haven't checked the pulleys with the belt off but the tensioner feels tight.

comrade - pull belt and spin alternator by hand quickly. if it growls or " feels " rough then the bearings are on their way out...time to replace....
just my .02 cents. cheers!

 

[Randomrunner12]

I will be doing that tomorrow. Has anyone installed a higher amp alternator on there vehicle?

I see that I can get a 180 or 220 amp if needed to upgrade my 160 and handle my extra accessories but seeing that it's recommended that I upgrade the battery cables as well.

 

[Hoefler]

Could be your transmission, when the lube warms up it quiets down.

 

[Randomrunner12]

It could be but I don't think so. This noise only shows up randomly. It also follows rpms when in nuetral and no load. Brakes are also normal and the pedal has no slop to it or extra stiffness.

I'm leaning towards the alternator but the sound seems to be coming from the driver side but not positive yet. Sound carries in these trucks.

 

[EZeis]

Do they use a one-way clutch pulley those years? If so, that can be going bad.


Earl

 

[Timd32]

You could check the FSM and see if they have the wiring diagram for the larger one and perhaps dual alternator set up if they were availabkr for your year.

It would list the wire gauge differences for them if any so you can make the harness correct.

The older ones are always better to get rebuilt if possible, not sure on the newer ones if the bearing kits are available. Or go to a local place that rebuilds them.

 

[AH64ID]

You should be able to go up to the highest OEM amperage without a wiring upgrade. I don’t recall why they had a 220 as an OEM option thou.

On my 05 I had the alternator rebuilt locally. If you can afford a few days of downtime that’s the best option, IMO. See if they can add any amperage. They couldn’t on my 05 136A, but on other rigs I’ve gotten more.

I will say that a single 220A is a huge improvement over the single 136A.

 

[seafish]

It could be but I don't think so. This noise only shows up randomly. It also follows rpms when in nuetral and no load. Brakes are also normal and the pedal has no slop to it or extra stiffness.

I'm leaning towards the alternator but the sound seems to be coming from the driver side but not positive yet. Sound carries in these trucks.

While more powerful alternators are available for these trucks, ( upgrading to the oem 220a or buying an aftermarket from Singer are both decent alternatives), it really sounds like you could save some money by spending more time with a mechanics stethoscope or a long wooden dowel to track down exactly the noise is coming from before you go throwing parts at it. Even if you have never used one before, they work very well to track down noises.

Just my .02

 

[Ozymandias]

Couple years ago when i was in need i bought a high amp alternator from this vendor on eBay.
Works perfect till today, would buy again.

https://www.ebay.com/itm/300-Amp-Ou...270500?hash=item2f26042be4:g:kucAAOSwOTZd3HPH

The above link is just a road sign to show direction, you would need to find the exact fitting alternator for your application.

 

[Randomrunner12]

You know I'm not sure. I don't imagine it does but can't really be sure either. I have found a rebuild kit that comes with new brushes and bearings as well as a pulley.

Might just order OEM from rock auto or something.

 

[Randomrunner12]

Well I just took the belt off and spun all the pulleys. None of the felt or sounded funny.

I have long screw driver at work that I can use but it had a rubber handle. Will that still work or should I just go buy the mechanics stethoscope.

I haven't started throwing parts at it yet just been researching to have an alternative ready for if I need to replace something.

 

[seafish]

Screw driver will work no matter the handle, though the stethoscope will be substantially louder and clearer and they are available cheap from Harbor Freight if you have one near you. Also a 1/2" x 3' wooden dowel from any hardware store works for extended reach.

To diagnose, it works best follow the VOLUME of the noise to find the culprit...ie as you get closer to the noise you will not only hear the noise more distinctly but also more loudly.

Of course, it is most important to not get whatever you are using CAUGHT up in anything that is turning.

 

[Randomrunner12]

Yeah that sounds like it would be a bad day lol.

I'll go to the freight near me and grab a scope and see what I can figure out.

 

[Timd32]

Can you run with no belt?

 

[AH64ID]

Can you run with no belt?

Yes. No water pump or alternator, but it’s fine for short periods.

 

[EDankievitch]

I would check to see if your Alt falls under the Alt re call they had 2 years ago before you spend any money.