G50 trans issues!

[James]

Ok I'm buying a rolling chassis that comes with a G50 transmission. From what I have heard from the current owner is it will shift into Reverse but no forward gears. I will know more when I pick up the chassis in two weeks.

I am planning on putting an Olds Aurora 32 valve DOHC TT 4.0 in the car. Desktop dyno is putting it at about 600-650 hp and 450ftlbs torque.

For right now I am wondering if anyone has links or sources for what I need to flip the tranny for use in a mid rear setup. I've heard it is better to put an oil sprayer in to oil the ring gear to help cool it and get the entire tranny oiled better since it is now upside down.

Also would it just be easier or better to just get a different trans all together?

 

[Peter Delaney]

Hi James,

If you were getting a decent G50 (and were not going to race the car), I would have suggested that you didn't bother with the sprayer - just flip the box, swap the drain & breather plugs, & use about 5 litres of oil.

BUT, as the box sounds like it will need to be stripped down anyway (5 working forward gears might just be handy !), I would suggest that it would be worthwhile to go the few extra dollars for the spray bar setup.

Then comes the bigger dollar option - better ratios. I ran my G50 with stock ratios for a while & it wasn't much fun to drive - the gearing was too low, especially at freeway speeds. I eventually had a higher 5th gear set installed & it is a much nicer car on the freeway - but I still have the "stump puller" 1st gear (which doesn't get much use), & there is quite a step from 4th to 5th - not ideal.

Not long after I made this change, higher ratio ring & pinion sets became available (damn !). A mate of mine here recently bought a complete rebuilt, warranted, sprayed G50 with the higher R&P from the US & is delighted. Let me know if you would like me to chase up the contact for you.

Kind Regards,

Peter D.

 

[Erik Johnson]

The G50 is a great gearbox for your application, with the correct modifications, in my opinion. A spray bar is not needed, if you install a good transaxle cooler and pump, which I very much recommend.

Heat is the biggest killer of gearboxes running in the inverted position. There are several things internally that need to be done, again in my experience, that many people do not consider.

New oiling area need to be drilled and installed so that you get adequate oil movement from front to back, and good overall oil cooling.

Many people do not do this, and simply change the file, drain and vent locations. This is not the best way of doing an inversion, as the oiling passages that were originally in place, are now on the wrong side of the gearbox, thereby limiting the amount of oil that actually circulates through the gearbox. Heat can build up as a result and issues can arise.

We can certainly help you and others with the inversion, as well as diagnose the forward gearing issues. Let me know when you get the gearbox in and I am sure that we can work something out to help you with your build.

It was good speaking with you, btw and I hope to be a part of your future build.

Warmest Regards,

Erik Johnson
Carquip Sales
(303) 443-1343 ext 2 work
(720) 980-9407 cell