Jerico Transmissions

Does everyone using a Jerico transmission use a cooler? My car is not a horse power or tork monster like a GT1 car. Probably have half the power of a GT1 car.
Terry
 
Mine, Dave's, Manfred's have rear end mounted belt driven 2 stage .400 gear width positive displacement type pumps on the rear ends, circulating gear oil through forced air coolers for both the rear ends and the Jerico/Tex transmissions. Temp gauges on each too. Others may as well.

The rear end is more prone to building temp than the transmissions, but keeping the gear oil in each below 220 makes a huge difference in the service life, and coolers are the only way to do that, even with REM or ISF processed internals.

Depends a lot on the weight of your car, and the power, and of course the ambient conditions.

Typical ambient temps around 70-80 aren't too tough to deal with. That usually means 210 to 230 degree temps in the gear oil, which is perfect to boil out any moisture and reduce viscosity to a reasonable level for lower frictional losses.

Spokane with it's 1+ mile long straight and many times 100+ degree weather can definitely result in high fluid temps, even with a cooler, sometimes up to 270 degrees. That's the upper limit of typical synthetic gear oils in my opinion for continued use and probably actually too high.

I hate to think what the localized temps are in the bearings themselves, which means excessive wear.
 
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Thanks Randy for the information. Sounds like I should plan on building a pump and cooler for my car. The car wieght is aprox 2410 lbs. and aprox 220 hp. Any favorite oil you would recommend?
 
We all run the off the shelf Mobil 1 75w-90, seems to work fine. Shucks, no Oreilly's (sp?) seems to usually have it at a competitive price of $8.99/qt. If you want to get fancy, the Joe Gibbs Racing product line has excellent options, at a premium of course.

At your weight and power, I would probably wait and see if you need external cooling. You'll need a gauge to read the temp, an electric sender in a bushing in the drain hole is an easy way to do it.
 
Can't speak for everyone with complete authority, but I'm pretty sure everyone upshifts without the clutch, just a quick throttle ease, and use a heel/toe type technique with the clutch on downshifts.
 
Do you use the clutch to up and down shift?

Everyone says that it's a waste of time and thought to use the clutch with a Jerico... But, we went 2 seasons on a rebuild when using the clutch on downshifts and only 4 races on another with no clutch at all!
 
Can't speak for everyone with complete authority, but I'm pretty sure everyone upshifts without the clutch, just a quick throttle ease, and use a heel/toe type technique with the clutch on downshifts.

The Jerico is a dog ring box. So, as you would expect, Randy speaks the 'one-true-way'. Others techniques may vary depending on driving style.

Always a good idea to carry a spare set of dog rings regardless of how good your technique is.
 
Having had this same question about my car (different parts, of course) I installed temp senders
in the diff and trans. Discovered that a good diff never got much over 100c. When it had
been whining for a while and kept getting louder, then it'd start to heat up- and I'd think
about putting together another. But it also proved I didn't need a cooler.

Haven't had the same trans in the car long enough to know the transmission answer... :(

but my .02 is that starting with a temp gauge will answer your question definitively.

Given what a royal PITA plumbing a cooler onto a stock- type diff is...

fwiw.

t
 
I have a GT-2 carf with a Jerico 4-sp transmission and a Speedway Super Max Rear end. I have measured the temps of both during a race and found that a rear end cooler is recommended but a transmission cooler is not. If you use the Mobil 1 oil in both you will be fine. I have tried several brands but Mobil 1 runs cooler and lasts longer. My car weighs 2080# with 345 hp in the engine. Good luck.
 
I have installed many dog boxes and raced a few in my Stock Car days. I would recommend at the very least install a gauge to monitor the temp of the trans.

Also to keep the wear down to a minimum use the clutch as much as possible. Rebuilding Gerico's can be costly and the extra time using the clutch will not really be noticeable in your lap times.

Adding a Tilton pump and a cooler will cost around $400 for the parts. Pretty cheap insurance for your box. The ambient temp, engine temp plus trans temp you will see around 250 on a warm day.
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Thanks everyone for the information. I will start with monitoring the oil temp and will add a pump and cooler if the temps are high. Anyone coming to the national race in Portland?
 
Those coolers are designed for RVs to pump cool & non aromatic fluids. They can be made to last longer if you make sure to specify a viton diaphragm rather than the ordinary buna type, but the diaphragms still have a very definite service life, usually no more than 10 hours. Then you need to do a rebuild kit for around $75. A couple of those, and you could have started with the all metal, designed for very hot gear oil, $400 Weldon 9200 pump. Regardless, electric motors performance degrade with heat, and are a less than ideal mechanism. An internal gear type ($$$), or external belt driven type (cheap on ebay) are the way to go. At least that's been my experience.
 
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