Rattle/grinding noise at 25-35 mph, mechanic told me AFM and lifters need to be changed.

[iboughtatahoe23]

2014 Tahoe 167k miles.

I’ve posted one thread about this recently that seems to have gone dead. So I’m making a new one.

Noise I’m having will usually happen from 25-35, mph when i accelerate around those speeds lightly. It seems to only happen in v4 mode and then when it “jerks” into v8 mode the rattle goes away. It’s a very audible rattle/scrape like dragging solid metal behind you. People look at me when driving down Main Street.

8/15/23:
Went to the shop again and took a ride. The mechanic told me i most likely will need lifters changed and it’s gonna run about $2500 or more.

On the other hand: My dad told me I should run 15w40 Rotella and I should be able to get another 150 K out of it but I think he’s blowing smoke just a little bit haha.


Wht you guys think? I’m kind of nervous to just take out a loan and throw money at some thing. But I’m pretty sure if it only happens when switching out of v4 and going into full V8 then I’m almost 90% sure it’s AFM related.

 

[Dustin Jackson]

Without doing any troubleshooting myself, a cheap way of finding out if v4 mode is causing your problem would be to buy a tuner or Range AFM disabler and turn v4 mode off and see if your problem persists, from there you can make a more educated decision.

It sounds like your dad is thinking of another Chevy problem but his idea wouldn’t help here really.

 

[iboughtatahoe23]

Without doing any troubleshooting myself, a cheap way of finding out if v4 mode is causing your problem would be to buy a tuner or Range AFM disabler and turn v4 mode off and see if your problem persists, from there you can make a more educated decision.

It sounds like your dad is thinking of another Chevy problem but his idea wouldn’t help here really.

Thanks, I was considering the range AFM disabler. Probably the cheapest fix tbh.but I have an issue where the radio lights draw power (left sunroof open and that’s what I get for doing that) and I’m afraid the disabler may run my battery dead on top of that radio issue. (I get slow cranks on the first start of the day sometimes)

Can it just be unplugged when not using it I suppose? Then plug it in before I start her up?


Lastly, is there any cheaper brands than the $230 range brand ones?

 

[Dustin Jackson]

@iboughtatahoe23 My thought behind the Range AFM disabler was we can take v4 mode out the equation if that is what you suspect is your problem. There are many different ways to go about turning off v4 mode, I would suggest you do your own research on those. I only have experience with Range AFM disabler and Black Bear Performance tune.

I wouldn't be worried about it drawing power while off, if it does you have other problems going on that aren't because of a OBD2 device.

 

[Dustin Jackson]

Cant you prevent v4 mode on a 6l80e tahoe by setting the Tahoe gear selector to M?

If so I would recommend doing that and seeing if you still have those symptoms.

 

[89Suburban]

Can it just be unplugged when not using it I suppose? Then plug it in before I start her up?

Yes it can. But I don't see the need to at all. This is a simple, must have for these trucks, unless you can do a tune or delete. Pricing wise even used ones hold their resale value. I would get one ASAP then go from there.

 

[iboughtatahoe23]

Cant you prevent v4 mode on a 6l80e tahoe by setting the Tahoe gear selector to M?

If so I would recommend doing that and seeing if you still have those symptoms.

Will try that thanks.

 

[iboughtatahoe23]

Cant you prevent v4 mode on a 6l80e tahoe by setting the Tahoe gear selector to M?

If so I would recommend doing that and seeing if you still have those symptoms.

I tried it and it didn’t do it.

 

[Dustin Jackson]

@iboughtatahoe23 Just so I understand correctly, when you put the Tahoe shifter in M mode and drive it like that you do not have the problem?

If that fixed your problem then I would recommend getting AFM tuned out of your Tahoe engine computer and continue to enjoy it until you have a lifter failure and then at that point I would recommend a mechanical AFM delete, no point in throwing money at the motor yet.

 

[89Suburban]

Or tow/haul mode should disable it.