rx-7fc

i have broke about three of them and one that i just rebuilt and wanted to know if cryogenic treatment will make it stronger because mine broke from the input shaft gear and part of 2nd gear and last time it broke all the teeth from the bottom shaft and input shaft teeth or is it that na trans are not that strong

silverFC

n/a are weak i broke 3 of them to i have like 170 rwhp
and toasted them did a t2 swap and its fine I have a t2 trans. for sale

Rxmfn7

iTrader: (4)

Hmm...while its true that N/A trannys arent as strong as a T2 tranny, 170rwhp shouldnt really be much of a problem. Mine has 123k miles on it, all original, and it still shifts very smooth, no problems at all. (ocassional grinding into 2nd when shifting fast) I dont really take it easy on mine at all either. How exactly did you guys break yours? There are a few guys on here with turbos and N20 using the stock N/A tranny, and from what I know it is holding up fine.

SureShot

Hmm - I wonder if he has the stock 30 Lb flywheel and dumps the clutch at 6k?

mikeric

iTrader: (20)

I have a turbo conversion but I'm still using my N/A tranny. Fine so far!

KNONFS

iTrader: (14)

Same problem here, I'm on my fourth one What clutch, PP are you using? What oil gear are you using?

In my situation (with a solid unsprung clutch), the first tranny wasn't acting up or anything, changed the gear oil to red line. Two months later, while redlining second gear, the input shaft took a dump!!

Replace the the tranny with a used one, filled with valvoline gear oil, decide to go with red line after 10 months of no problems what so ever. Bearing started making noises not even a month after replacing the valvoline gear oil to red line!!

Again, replace the tranny with a used one, and used valvoline gear oil. The red line trend wasn't working for me, so havoline was the one. After a year or so, I had to replace the clutch, while a friend was helping me out, he suggested red line shock proof (or something like that). I must say the tranny felt like new after replacing the gear oil with the shock proof stuff......... But what do you know, 3 weeks later something went run, taking apart a gear (or gears, tranny is waiting to be dissasemble), along with a bearing.

Moral of the story, either:

-Don't buy used trannys
-Don't use a solid unsprung clutch
-Don't use redline oil

OR ALL OF ABOVE

SureShot

A short story... I was getting used to my 91na 127000mi – shifting from 5th to 3rd at 70mph without going through 4th. It worked fine, but as I slowed down to about 50, I downshifted to 4th, and BANG SCREEEEETCH, the wheels locked up. I popped it out of 4th >BOOM< and limped home in 5th. I pulled the tranny in the driveway, took it apart, and found the lock nut on the main shaft had come loose, backed up & jammed 5th so tight I had to chisel the thrust collar off. It cost me $60 for the parts (2 lock nuts, thrust collar & retaining rings). I took a chance the bearings were OK and put it back in.
It was 2 years of enthusiastic driving later when the input gear finally broke out a tooth.

SureShot

A tip for longer transmission life:
Unless your in a race, launch softly, then WOT and short shift to 2nd (about 6k).

For example: short on-ramp video

rx-7fc

i think that redline is not that good too because thats what i had in my frist trany and them it went out and then i used valvoline on the next one and it was ok and about a year later 2nd gear went out but it was because it was grinding a lot and then the one i rebuilt i think that i did not tighten the lock nut enough

Kenteth

my oldie had about 136k before all the gears went. Now shes got a temperary trans that has 83k on it. Like driving a new car Lining up parts for a manual swap though.