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13K views 74 replies 32 participants last post by  ToeKutter 
#1 ·
If you do one mod, it needs to be changing to the 3.09 gears.

I had mine changed to 3.09 from the stock 2.62 gears today and my car feels like a new car. The snappiness is insane, I can't explain how but it feels like someone added 150hp. It feels lighter, it handles with more authority when you step into the gas.

I wish I had done this much sooner.

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Contact whoever you need to contact. This one mod is the real deal.

No, it doesn't void your warranty. Buy from a Mopar dealer, have them install. Problem solved.
 
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#4 · (Edited)
If you do one mod, it needs to be changing to the 3.09 gears. * * * Contact whoever you need to contact. This one mod is the real deal.
No, it doesn't void your warranty. Buy from a Mopar dealer, have them install. Problem solved.
You're in Canada, dude. Maybe nobody reads the paper work or nobody cares, :rolleyes: but down here if something breaks after the switch, like the DS, the changed gearing will be FCA's "out" to void the warranty on you if they want to, which means you risk footing the bill for replacement or repair.

Not sayin' the switch to 3.09 gears isn't a great mod. I'm sure performance is much improved. But maybe FCA/SRT should've offered it as a factory option from the git-go, huh?
 
#10 ·
Thanks for telling me where I live. I wasn't sure. :cool:

Yes, It should have been offered as an option, especially since the new Demon comes with the 3.09's as well as factory.

This is an official Mopar part, not a Mopar P-Part (Performance) and it is covered under warranty if purchased and installed at the dealership. If it was a P Part, it's not covered.

There are several cars with stock driveshafts in this very forum with 50-100+ pulls and no issues on stock DS.

If you have a 15, yes - your DS is weaker than 16/17 and you might have issues. Dodge will replace up to two DS's on 15's under warranty.

FCA increased the strength for 16 and it's my understanding the same part is in the 17's, and they don't have issues. Then again, if you're building a drag car... the gears are the least of the issues you might have. The pulleys get the voided warranty. If you've flashed your ECU with a tune, it's also gone. Some people think they can switch the ECU and no issues but there are other parts of the car that record there was an ECU swap made. So if you tune your Hellcat, your warranty is voided.
 
#6 ·
That's Right! 309 Gears still are my favorite mod my husband Top Cat had installed on my Charger!

For a surprise for me, he had HHP install them and asked Josh not to tell me. My HC Charger was first to have the 309 gears installed!
Top Cat's HC was first ever to have the 309 gears installed and think about the Demon?
Just think, Dodge was starting the build around the same time. Many similarities.;)

Top Cat wanted Josh to keep the surprise and not tell me about the gear switch but Josh was a bit worried.
That night he said to me "Umm I had your car on the Dyno today ( Truth ) and tonight you will feel a kick in the seat of your pants. I'm thinking Okayyyyyy:cool:
This was back when my car was still in the process for the R&D and T&T of parts, it seemed like every 10 days something changed.


And BTW after the gear switch, my Best 60 ft was a 1.40 Top Cat's was 1.38 with the change of the 309 Gears.
My car gained .2 in my ET and I love the difference in the launch from stock gears. Way more fun at the track!!!
The 309 gears make the car take off like a race car should!
No Tuning required.

~ Linda :)
 
#7 ·
You really can see the launch difference.


OEM 262 Gears





309 Gears
 
#25 ·
Not on Drag Radials... ;)
 
#13 ·
You're in Canada, dude. Maybe nobody reads the paper work or nobody cares, :rolleyes: but down here if something breaks after the switch, like the DS, the changed gearing will be FCA's "out" to void the warranty on you if they want to, which means you risk footing the bill for replacement or repair.

Not sayin' the switch to 3.09 gears isn't a great mod. I'm sure performance is much improved. But maybe FCA/SRT should've offered it as a factory option from the git-go, huh?
All other factors being the same, the 3.09 diff will REDUCE strain on the driveshaft at launch. It's the same as grabbing a ratchet with a longer handle - it takes less effort to break the same bolt loose than with a shorter handle. As long as the diff was bought from a dealer and installed by a dealer (and that might not even be necessary as long as a qualified mechanic did the install) it shouldn't cause any warranty issues. SHOULDN'T. Talk to your dealer.....

Also, I'm pretty sure it's still a 200mph car with the 3.09's - and it might even get there quicker. I suspect the 2.62 ratio was chosen to help with EPA efficiency requirements more than anything else.
 
#15 ·
Okay, thanks. Interesting comment there on the reason FCA went with 2.62 from the factory, and not the 3.09s.

Yeah my Cat is a mid-2016, so it's got the newer DS, but I'm not tracking it anyway. I do run Nitto DRs though. I'll talk to my dealer and his service manager and see what they say, as I know both pretty well.
 
#22 ·
That works too
Do you by chance have 309 gears?

~Linda
 
#23 ·
Just curious how you run 9s with no rollbar and thats the hangup with the Demon? I thought 9.90s even on a production car was rollbar time? Just curious as I see a lot of 9 second passes without cages
Technically, we should have all been relegated to 5pt roll bars as soon as we ran 11.499 or quicker, and 10 pt cages at 10.99 or on cars that exceed 135mph. Stock, unmodified bodies running 10.000 - 10.999 can have a 5pt bar. All of these cars will then also need date coded 5 pt harnesses as well. NHRA has been letting the new supercharged cars run as long as they are completely stock, down to 10.00, at which point it's cage time. We were told at Cecil that even the addition of a DSS driveshaft could result in tech requiring the rest of the safety gear including a cage, but as long as they don't see it.....
 
#24 ·
You are correct about my videos. 1 is untuned 262 gears The other is tuned with 309.

But The OP said it all and the same goes for a tuned track car.
I did look around for a video of a couple guys I knew that had their cars tuned and still had 262 gears. After seeing my car launch they changed. They are not posters on here and 1 is a grudge racer. Maybe someone else can provide video of apples to apple comparison.:cool:

I can tell you the Demon comes with 309 gears for a reason;)

~ Linda:)
Ok, another video my car. It is tuned and still has 262 gears. It is still not apples to apples, I was at the Track for R&D and T&T of tuning parts and we were adding something weekly.


 
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#26 ·
#30 ·
So you're swapping in a factory Mopar part and connecting it to factory Mopar parts...and somehow the latter parts are void?

Tell them to remove their heads from their collective arse.

Find a new dealer.

On an aside, has anyone noticed reduced fuel mileage at all? I drive mine everyday I can on the highway to work, just curious if it's noticeable or not.

This might be my next purchase!
 
#31 ·
So you're swapping in a factory Mopar part and connecting it to factory Mopar parts...and somehow the latter parts are void?

Tell them to remove their heads from their collective arse.

Find a new dealer.

On an aside, has anyone noticed reduced fuel mileage at all? I drive mine everyday I can on the highway to work, just curious if it's noticeable or not.

This might be my next purchase!
No difference in fuel mileage that I have noticed. In fact at 80mph the RPM`s are only increased by 300rpm`s. Was at 1700 rpm`s with the 2.62`s and now at 2000rpm`s with the 3.09`s at 80mph. The A8 has plenty of gears to keep everything sorted and reasonable. In my experience and opinion the gear swap was beneficial and something I would do again - as stated before the 392`s and the new Demon all have the 3.09`s so that should tell you something right there. For me the $1500.00 bucks for the differential and labor was worth it, certainly better than a $500.00 CAI that in my past SRT`s I could never feel a seat of the pants difference by having -- Good luck!
 
#32 ·
Well, this will be one of the many mods I do if I'm not able to get the Demon, but right now I'm holding off on doing anything that I won't see a return from until after I know if I'll have won the lottery or not! :)
 
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#36 ·
My dealer said it would be a problem.

I didn't car for the 3.09's as much. Liked the longer legs on the 2.62's. but that's just personal opinion.
I'm sure the 3.09's are quicker.
 
#37 ·
I have a Scat Pack AND a Hellcat.

I might just swap the diffs between the 2 cars. It certainly wouldn't hurt the Scat Pack as far as fuel economy and it'll have a little higher top speed even. The wife drives it anyway, so........
That's Cool !!!
 
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#39 ·
So it would appear that this is a huge improvement to the factory HC driving experience.

If you were not to track the car and maybe take it to a few drag events, would this be your first mod? I'm going to call my dealer and get a quote, anyone happen to have the part number off-hand? If not, I can ask the interwebz to provide an answer.

I might do this sooner rather than later, I remember seeing them on here priced around $1.1-1.2K.
 
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