Jerico, G-force dog rings longevity?

Ant · #1 (**permalink**) 07-14-2005, 02:58 AM

I would like to hear from users running the Jerico or G-force transmissions for race and maybe some road, on how the dog rings stand up for longevity?

I read on a forum this guy had a GF-5R and it did five drag days and the third gear dog ring needed replacing, I am thinking this guy may be very hard on gear or why would I want one of these transmissions in my Cobra!

Having said that maybe it could take foreever to get up enough miles for things like that to wear out!

David Kee · #2 (**permalink**) 07-17-2005, 07:04 AM

I used a Jerico in a drag race application in a 3100# car. I put at least 75 passes in the 10.70 - 10.90 range and started to wonder about the dog ring wear. I pulled the cover to check the wear and could see almost none.
I do know that you can not baby the dog ring gearboxes, when it is time to shift you must change into the next gear quickly and firmly. If you try to shift slow it will make very unfriendly noises and beat up the dog rings and sliders over time.
You should get a decent service life out of this type of gearbox, it will last allot longer than a factory synchronized transmission.

Ant · #3 (**permalink**) 07-17-2005, 03:21 PM

Thanks David

I think I have beaten this topic to death!
I have considered a Jerico to the point where I had a deposit on one with Jerico but canned it a few weeks ago, thinking that the T56 G-force would be better with triple cone syncros, but I have my doubts about the syncros lasting, and with the straight cut boxes I have read where the gears have a lot shorter life span than a helical gear!

My car is for road race with a 630+bhp Nascar alloy engine etc, and will be road driven for fun so its going to see 8000rpm which will be tough on a syncro box I think, but maybe one of these triple cone setups might do it!

I havent given up on the Jerico idea, as I think the road race slider version has maybe a better dog ring system than some others, plus mention has been made of using drag race softer gear material on the road etc, but apparently the road race harder gears last longer?

David Kee · #4 (**permalink**) 07-17-2005, 05:49 PM

You may end up with a Cup transmission they use on the road coarses. The oil cooler may not be a bad idea either. If you do what Jerico suggests with the oil type and brand it may last longer than you think.

I have one of those high horsepower small blocks myself, ours dynoed at 700hp at 7400rpm with one 950cfm carb. We are sorting out the some bugs in the brake system right now. Then we can start adding nitrous. We need about 1000 horsepower to be competitive. I can't wait to run a Jerico 5 speed in it.

Ant · #5 (**permalink**) 07-17-2005, 10:29 PM

David,

Thats going to be a machine when you sort it!
We had them out here but they were a four door Falcon, but I reckon the two door looks great.
Regarding the right oil and temperature etc, and as you say if you do the quick positive gear change, even at partial throttle, with the right oil it should last, and I dont see a problem with changing the dogs when they need it, as everything wears out. You mention a Cup box, that would be a four speed? - I reckon with my engine five gears would be better, as I dont really want to change rear ends between race and road!

Rory428 · #6 (**permalink**) 03-07-2006, 11:33 PM

I know that this is an old thread, but I just ran across it. I have been running a Jerico DR4 in my low 10 second 428FE powered drag car for over 6 years now. I run the car regularily, over 100 passes per season.Dump the clutch at 64-6600 rpm, shift WOT at 6200 RPM, and I couldn`t be happier with the Jerico. I pulled it out last year, to try some different gear ratios, and we were able to re-use every dog ring over again. They had some minor chipping on the edges, but otherwise, still look (and work) fine. I have no idea how it would work in daily street use, plus they are noisy & clunky, plus I never downshift mine, so I doubt the drag race version would be ideal for a roadrace application. But I bet a NASCAR version would be OK.

Ant · #7 (**permalink**) 03-07-2006, 11:46 PM

Rory

I have the RR5 Jerico, and I am hoping when I get operational .......long way off yet, I will master the changing, I have had some experience with this type of box, but I dont mind replacing dog rings if I have to!