Nothing real technical here...but I had to pull the trans out of the Vette to fix a pesky lube leak it developed. Had to split the case and reseal everything.

Just thought I'd post the inside of a GF5R trans in case you haven't seen one before. It's a race trans with no synchros, straight cut gears etc...but man I love this thing! Everytime I look at one...it just makes me feel good! What you can't see is the really neat way the shift forks work. They slide on an internal rail/shaft arrangement so they stay stable and straight. Still uses an external bolt on shifter (Long..another great piece!)..but on the other side of the shift levers insode the case it's a whole different world.

I haven't opened it up in about 10 years or so....when I changed a couple of gears to re-gear it to match my power curve a little better. It's been bullet proof as opposed to the old Doug Nash it replaced. The Nash was great..but when we got into the 800+ HP range it had a tendency to shear the teeth off 3rd gear pretty regularly. Got expensive!

Also thought it was cool to still see my name still written inside on each of the case halves. When they build you one..it's for YOU!!

JIM

 

It looks like it is very easy to work on. I did not know that a doug Nash would even take on a 500 hp bbc?

 

Yea same here Jim, surprised the Nash handled both you and that much hp lol! That thing may look like a Richmond/Nash on that outside, but looks a little different on the inside for sure. Very cool. Looks like new! You have given me hope that the Richmond I will be putting in my 69 will survive 650 or so hp.

 

Looks sweet!

I have never driven one but it looks very strong. Sort of reminds me of an older Fuller transmission on the bigger trucks.
How do you slow the rotating mass when you go to put it in gear? I don't see any type of clutch brake or anything.

 

The Nash did well up through the 750 HP or so range. I was using a Centerforce DF clutch even behind the 540 version of my engine. That probably saved it a lot. When the engine power went up..the Centerforce was no longer able to hold it. If you "flat footed" it with any sort of traction at all...even running 50 mph...it would start to slip and never recover. I went a little overboard probably and installed a Mcleod dual disc clutch with some added base pressure. That sucker wouldn't slip no matter what I did. On a launch it would drive the tires into the pavement. I'm sure it didn't help the life expectancy of 3rd gear! I used same clutch for awhile with the G-Force...but later moved to the McLeod Soft-Lok clutch which made everything work well for the type of driving I do. hardcore parts for sure, but they work for me.

It is very similar a Fuller trans actually. No problem getting it in gear as long as clutch is adjusted right. It can be a little "clunky" in daily use...but actually shifts OK at low speeds...REAL NICE at 7500 RPM! The only thing somewhat noticeable at times is the "slop or play" in the system as you let on and off the gas or if you get the engine in a "bucking" mode. There are big slots in the sliders and the gears that can bounce back and forth sometimes..but as long once you're either acclerating or decelerating it's solid. Not really that noticeable..but I probably drive it knowing what it does and keep it out of that mode.

JIM

 

Looks cool, nice straight cut gears. In my experience I have blown three trannys and everytime it was 3rd gear. I don't know why 3rd seams to be the problem, any ideas ?

 

Interestingly when I was spec'ing this trans years ago..3rd is the one they worried about too. Not really sure..but you're right...it's a common one when you're making power. You would think first gear with launching...or maybe 2nd...but they weren't concerned about them at all.

JIM

 

Motorhead, If you actually find the specs on most transmissions their is a different TQ spec for each gear. 1 + 2 are usually the strongest and top gear is stronger than the middle gear or gears because the most time is spent in it.

 

There is the key to those 7500 rpm shifts right there.
Very nice.