Replacing 5th gear

[John Baird]

How hard is it to replace just 5th gear? Just ran the 1/2 mile this weekend and the car stops pulling after shifting into 5th. It needs for 5th to be closer in ratio to 4th gear. Can you replace just 5th gear?

[Dan Cragin]

It requires special tools. Not something you would want to try yourself.

Dan

[DEMO MAN]

How hard is it to replace just 5th gear? Just ran the 1/2 mile this weekend and the car stops pulling after shifting into 5th. It needs for 5th to be closer in ratio to 4th gear. Can you replace just 5th gear?

What did u run in the 1/2 mile? Is your Viper stock?

[John Baird]

Stock 2017 GTS, 149.7mph. What's it gonna take to make 160mph? In my question above, I meant can you just replace 5th gear, with a lower ratio. How much would it cost to replace the gear in the transmission.

[EvilWon]

I've run 158.8 two years in a row with just an arrow ecu and smooth tubes. Everyone I've talked to says my car is a freak of nature though. I keep debating headers but everyone tells me it's both worth the money and I have other projects I'm working on where $3500 would go a lot further.

[Bill Pemberton]

Just get in touch with Dan Cragin who responded to you. You are right there in his home state and he is considered by many as the best Viper mechanic in the Country. He has been working on them since the 90s, so save yourself time chatting with many folks who may have just gotten a Viper and give Dan a call -- or PM him now!!

[DEMO MAN]

Stock 2017 GTS, 149.7mph. What's it gonna take to make 160mph? In my question above, I meant can you just replace 5th gear, with a lower ratio. How much would it cost to replace the gear in the transmission.

The biggest issue u would have keeping u from running faster is that 3.55 differential forces u into 5th gear before the 1/2 mile ends. I have a 2010 and stock ratio is 3.07, I swapped that for a 3.21 and my car will run 159+ in the half and I only need to go to 4th gear. That single change in my opinion will make the biggest difference in your speed. Plug in your values in this and u can see what it will do for your runs.

http://xse.com/leres/bin/gearratio?title=SS+%23670+with+MM6+manual+and+3.73 +gears&rpm=6400&mph=55&gear1=2.26&gear2=1.58&gear3=1.19&gear4=1.00&gear5=0.77&gear6=0.63&reverse=2.90&axle=3.55&diameter=24.94&circumference=78.35&revs=809&tire=wheel&section=355&profile=30&wheel=19

[John Baird]

Thanks Demo Man, but I can't get your chart to work for me with a 3.21 gear

[slowhatch]

I have the .80 5th gear in my car from the 2010 ACR and the car pulls like a freight train on the top end.

[drabe]

How hard is it to replace just 5th gear? Just ran the 1/2 mile this weekend and the car stops pulling after shifting into 5th. It needs for 5th to be closer in ratio to 4th gear. Can you replace just 5th gear?


I have the same problem at Mosport down the back straight. It falls right off

[Racingswh]

Stock 2017 GTS, 149.7mph. What's it gonna take to make 160mph? In my question above, I meant can you just replace 5th gear, with a lower ratio. How much would it cost to replace the gear in the transmission.

I did a bunch of studying on this and it looks like a 3.73 differential gear with a .84 5th gear would be your best option with the 27.4" tall rear tire with a top speed of about 169 at 6500 rpm. I am guessing Dan can help you out with what you need.

I was going to look into doing just this during the off season.

[Brad00GTS]

I will order my pulley when you order your new transmission, ha!!

[Jack B]

There was a .84 aftermarket gear, I do not think it is still available. The .84 grows physically in size, therefore, the case might have to be modified for interference.



I did a bunch of studying on this and it looks like a 3.73 differential gear with a .84 5th gear would be your best option with the 27.4" tall rear tire with a top speed of about 169 at 6500 rpm. I am guessing Dan can help you out with what you need.

I was going to look into doing just this during the off season.

[Arizona Vipers]

There was a .84 aftermarket gear, I do not think it is still available. The .84 grows physically in size, therefore, the case might have to be modified for interference.

The Gen 5 Camaro's had the .84 in them, so they have to still be around I'm sure. I've got the .80 in my '13 now, but am looking into getting the .84 soon.

[PkB2014]

Any thoughts on a 0.68 6th gear to go with the 5th gear change? The standard 0.63 seems easy enough to find, but 0.68 seems a bit more rare.

[RedTanRT/10]

AZ, talk to Dan. I looked into this a few years ago for my G4. Seems like he uses (used) the 5th gear from an Aston Martin

[ViperPete]

Changing out the rear end would be a lot simpler. I ran 157xx in my car many times and 5th does suck.

[Arizona Vipers]

Changing out the rear end would be a lot simpler. I ran 157xx in my car many times and 5th does suck.

And the ACR is MUCH worse. Feels like you opened a parachute out the back when you shift into 5th. The first time I shifted into 5th on a track in the ACR, i thought something was broke, it didn't even feel similar to the '13.

[Jack B]

The Gen 5 Camaro's had the .84 in them, so they have to still be around I'm sure. I've got the .80 in my '13 now, but am looking into getting the .84 soon.

A 13 could be a .765. Merely divide 4th gear speed at 3000 rpm by 5th gear speed at 3000 rpm, that will give you the 5th gear ratio. You can compare at any rpm, however, the higher the rpm, the better the resolution or accuracy

[Racingswh]

And the ACR is MUCH worse. Feels like you opened a parachute out the back when you shift into 5th. The first time I shifted into 5th on a track in the ACR, i thought something was broke, it didn't even feel similar to the '13.


Correct and unfortunately I use 5th everywhere. Right now it's a 2,3,4,5 car. At least with the 08 and the 3.07's it would go mid 160's in 4th. With a move to a shorter final drive and 5th gear it makes it a more effective 3,4,5 car that won't fall on it's face in 5th. I have a little more mechanical advantage than the OP because like you I run a 26.8" tall tire.

Like bas been suggested for the OP if he didn't want to change 5th he could go the other way with the rear end gear so he doesnt have to use 5th. It will do the 1/2 in 4th. The problem then becomes if you ever do shift to 5th acceleration will be non existent.

Once again the reason I have sequential box envy and their plethora of ratio options. It always gets back to that. :)

[Racingswh]

Any thoughts on a 0.68 6th gear to go with the 5th gear change? The standard 0.63 seems easy enough to find, but 0.68 seems a bit more rare.

What is your thought on the benefit? The car needs to make more power (like a TT setup) to use it as a top speed gear. Currently it struggles in 5th. I have nothing against more power though. :)

[Racingswh]

There was a .84 aftermarket gear, I do not think it is still available. The .84 grows physically in size, therefore, the case might have to be modified for interference.

Interesting point and something I will more seriously research. Otherwise it makes more sense to put in a taller final drive and all but eliminate the need for 5th. Like both of my Wife's cars and 3.42's. Rarely is 5th used for what we do.

[PkB2014]

What is your thought on the benefit? The car needs to make more power (like a TT setup) to use it as a top speed gear. Currently it struggles in 5th. I have nothing against more power though. :)

Not my car. A friend that went with me to the Texas Mile hit the limiter in 5th, and 6th is worthless at 0.50. A 6th gear @ .68 would still give a top speed of 206-211 depending on tire size and should pull well enough to see improvement in the mile events. 0.63 would be an improvement over .50, but not sure if it is ideal for a mile event.

[RedTanRT/10]

Once again the reason I have sequential box envy and their plethora of ratio options. It always gets back to that. :)

Racing, I'm with your and love mine;

1st) 2.760 2nd) 2.056 3rd) 1.598 4th) 1.296 5th) 1.112 6th) 0.958

But changing 5th is a whole lot cheaper!!!!

[Racingswh]

Racing, I'm with your and love mine;

1st) 2.760 2nd) 2.056 3rd) 1.598 4th) 1.296 5th) 1.112 6th) 0.958

But changing 5th is a whole lot cheaper!!!!

Look at that. I love that!! Interesting how short 5th and 6th are. What's final drive?

Just take top speed for the tracks frequented and back down through the ratios in 1500 or so RPM increments. Basically match it to the dyno sheet from 5000 or so to 6500 rpm and set the ratios. Here's my wish list. :)

Stock 3.55 Final

2.60 1st

2.06 2nd

1.69 3rd

1.35 4th

1.08 5th

.86 6th

Thanks for the sobering reminder that it's cheaper just to find another 5th gear. My Wife would probably say the same thing. lol!! Thanks!!

[RedTanRT/10]

Racing,

Stock 3:07's. Lightly modified motor (headers/cam balanced/BP), not sure of the G2 redline, 6300?? Dan Cragin told me it will top out at 174, I saw 163 at CA Speedway in June.

Hasn't been dyno'd yet, I think about 575 at the crank. I ran with a guy in a stock G5E and was able to easily pull him on the oval from say 80 mph on.

I tell my buddies, compared to a T-56 or T6060 in a G3 or 4, My 3rd is you second, my 4th is your third, my 5th and 6th straddle your 4th.

A whole new track learning environment coming our of an '08 G4.

[Racingswh]

Not my car. A friend that went with me to the Texas Mile hit the limiter in 5th, and 6th is worthless at 0.50. A 6th gear @ .68 would still give a top speed of 206-211 depending on tire size and should pull well enough to see improvement in the mile events. 0.63 would be an improvement over .50, but not sure if it is ideal for a mile event.

That car must make good power. Sixth is exactly what you say. Anything shorter will be better than the .50 of course.

If I was doing a mile event I would pick a top speed I wanted to hit and gear the car to do that. Then make enough power to make it go that fast. Power does wonderful things for cars that are geared correctly and have decent aero. 1600-2000 hp get's you scooting right along quickly. PITA to maintain though usually if that matters.

A guy in town had his shop build him a fast Dodge a few years back, 252 mph in the Nevada Silver State classic. It's not a a mile event though. It's open road driving. He did that with careful attention to slippery aero. Made good power too of course.

[Racingswh]

Racing,

Stock 3:07's. Lightly modified motor (headers/cam balanced/BP), not sure of the G2 redline, 6300?? Dan Cragin told me it will top out at 174, I saw 163 at CA Speedway in June.

Hasn't been dyno'd yet, I think about 575 at the crank. I ran with a guy in a stock G5E and was able to easily pull him on the oval from say 80 mph on.

I tell my buddies, compared to a T-56 or T6060 in a G3 or 4, My 3rd is you second, my 4th is your third, my 5th and 6th straddle your 4th.

A whole new track learning environment coming our of an '08 G4.

So nice. Impressive what good gearing does especially when coupled to a car that is set up well and makes good power. Your's are about perfect to me and the thing doesn't have to go faster than 174 unless we here in the US are meeting up at Daytona!! That could definitely be fun!!

I certainly get the OP's desire for a better 5th. I have it for sure. An 18" wheel on the rear with a slightly shorter tire 345/35 helps a little too.

I am just happy to be driving this weekend and the weather looks like it will be perfect!! So many cars though. Should be a wild time!!

[John Baird]

What would the speed be at 6200rpms in 4th gear with a 3.23 rear end?

[Steve M]

What would the speed be at 6200rpms in 4th gear with a 3.23 rear end?

Assuming a stock Gen 5 rear tire (355/30/19), you'd be at 156.35 MPH.

[John Baird]

Thanks Steve, so I would have to go back to a 3:07 to hit 160mph in 1/2 mile in 4th gear?

[Steve M]

Thanks Steve, so I would have to go back to a 3:07 to hit 160mph in 1/2 mile in 4th gear?

Well, the stock rev limit is 6,400 RPMs, which would get you to 161.39 MPH. The Arrow PCM bumps that another 200 RPMs to 6,600, which would get you to 166.44.

[SolidViper]

Is this also the case on fifth gear with gen 5 twin turbo cars ?

[PkB2014]

Is this also the case on fifth gear with gen 5 twin turbo cars ?

Power solves a lot of acceleration problems. ;)

A calculator was posted on the first page, but I'll put this link for the Tremec website calculator again so anyone wondering about gears and speeds can play with it and see the numbers themselves.

http://www.tremec.com/calculadora.php