I'm planning on upgrading my Vette from a Doug Nash street 5 speed to a G-Force 5 speed race trans.

It will bolt right in my car, so that part is easy.

What I'd like to know is if anyone has ever run one on the street? How does it really shift at WOT?

Do you have the clutch or clutchless version?

Will the clutchless one downshift at all? I've driven old style crashboxes with removed synchros etc on the street and made them work fine. How does this compare?

Any durability questions with gear materials if you took it on a long highway drive? 1000 miles?

Thanks,


JIM

I knew it would eventually happen, the cage is next tongue.gif

You gonna buy a new one Jim ?

As far as I know, a clutchless tranny can't be used on the street. The kind with the tapered dogteeth. The way they work is that you take your foot off the gas and the deceleration works on the taper and pushes the tranny out of gear.

Any time you take your foot off the gas on the street, you'd pop out of gear.

The clutch assisted ones, don't have that taper so you have to momentarily disengage the clutch to remove the engine force to pull it out of gear yourself. Don't need to have the clutch disengaged to put it in gear, though.

Tim.

"540"
I really dont know how G-force clutchless 5 speed works on the street personally. But about 8 years ago in Hawaii. I knew a guy who had a G-force 5 speed in a 90'iroc with a 400 sbc. It ran deep 11's back then and he drove it all the time. It did sound like a semi when he put it in gear in the staging lanes, but it ran good. He said it topped out around 160 mph on H2 on the top end.

A few years earlier in Hawaii, A local guy had a 69 comaro with a "4XX" sbc with a jerico 4 speed. He had it set up to use the clutch during the launch and not during the pass. Any way he drove the car all the time and the best I seen it run was 10.40's before I left the island, and that was on the motor. Eventually he got the car in to turbo magazine once he put the "gas" and a glide in it to pull off a 8.90 It was a true street car.

TronDD As far as I know, a clutchless tranny can't be used on the street. The kind with the tapered dogteeth. I'm not up on the drag manauls, but I think you're thinking of a crash box. A converted 4spd.
Motorcyles have used dog teeth gears forever. The drag bikes have the neutral on decell thing though.
If the taper is correct, they won't pop out.

The Gforce is a Richmond 6spd with stronger alloy gears, maybe not all of them, 6th removed and a center shaft support installed. There is probably other things too. There're rated at 1000ftlbs I think. I lost interest when I got the price. A Jerico is cheaper.

a friend of mine runs a g-force 5 speed in his 65 chevelle, it is a clutchless design and cannot be driven on the street-he even has trouble getting back on the return road, the trans pops out of gear when he lets up on the gas. Sure sounds good going down the track though---can't hear it shift it's so fast. I guess there is also some sort of shock absorbing deal built into these trannies. I've been kicking around getting the road race version of clutch assisted for my car but wow they are expensive.

540 HOTROD, interested in selling the Doug Nash?

Thanks guys..

I've driven a clutchless Jerico also and it was killer. Unreal how much fun it is to hit gears in one of those things!

The only reason I don't use a Jerico is I want to keep my highway cruising gears. You know...I want it all!

I spoke with them again today. They seemed a little surprised to hear the "1000 mile cruise" question. He said it would work Ok but he recommended their lube that is 140w to make sure it would live. Otherwise he recommended a cooler setup. Not too practical for the street.

There is a torsion bar version just like the old race Nash's. But it makes fitting it in there tougher and he said ground clearance isn't very good in a street application.

The regular version is rated for around 1100-1200 hp in a 3200# car. The torsion bar one moves it up to 1300+ HP.

You have no choice but to buy a Long shifter. They won't sell trans without it unless you are a regular customer that they know already has shifter.

Getting speedo gear stuff is a no cost option.

They said my street twin Mcleod clutch would be fine, but recommended backing off static pressure to 1100-1200 to allow some slippage on shifts.

I figurd so, but I asked anyway. The clutchless ones will definitely come out of gear just as easily as they go in. Have to hold it in gear. Man that would make it tough to hold my Super Big Gulp!

I'm in sticker shock too! Gonna have to have a heck of a garage sale to swing this deal!

I already have a guy that is buying the Nash. It's like letting go of an old friend! If you can find one, they're great!


JIM

I HATED my doug nash 4+1 street transmission graemlins/angry.gif

damnit, I want a 5 speed :mad: anything good on the market that isnt a fortune? :D

I second a 5spd want but what is available on the market for a 1st gen. and is reasonably priced? I need something to fit a motor moaking around 500horses/500ft.lbs.

Jim - We run a Liberty 5-speed clutchless and the design concept is the same as the G-Force clutchless. It pops out of gear on deceleration and you have to bring the car to a complete stop in order to put it back in any gear. Definitely not meant for the street.

baddbob71 and pnutkemist - I have a fresh Richmond 5-speed, pro-shifted by Liberty with a Long V-gate shifter for sale. We used it behind a 575hp/510lbft sbc. Drop me an email if you're interested.

This makes me curious about the Chevy ZL1 Concept Camaro. It uses a G-force 5 speed, definatly a clutchless version from the vid i got of Mike Moran slammin the gears without letting up. However, during the Car and Driver test they did on it, they ran the car on the road course. THey said they used 4th and 5th gears mostly, but on a road course you still have to spend a ton of time decellerating. So maybe they got somethin out there that is streetable. Call G-force, and/or Jerico, Lenco, or Liberty, and see if they got any trannies that are what your looking for.

-SS454- I didn't see the Car and Track article, but I suspect that they were testing the GF-5R. This is available as both clutch assisted and clutchless. My experience is with the GF-2000 which, along with the Liberty, are the two trannies used almost exclusively by all of the Pro Stock teams. Indeed, all of the companies you mentioned (I would include Tremec in the list)make "streetable" versions of their "race only" transmissions. As I often say, "pay your money, make your choice and live with it".