C3 Race Car Build
- Thread starter Oneball
- Start date
Daytona Vette
Well-known user
Something to do with the Factory assembly line I believe, Just filled / sealed with the windscreen "Dum Dum" at the Factory (can be a concern for leaks)
Oneball
CCCUK Member
Thanks DV I’ll just weld it up.
Oneball
CCCUK Member
Turned a little corner this evening.
Diff cover removed. Unfortunately the mounting holes have been stripped at some point so that’ll need a new one.
Diff carrier out in preparation for a rebuild with new bearings and clutches. Going to go with the existing ratio of 3.36:1 which will give 177mph at 7500, so a bit on the long side but we’ll see.
Case cleaned and painted. First shiny bit completed instead of disassembling rusty crap.
Diff cover removed. Unfortunately the mounting holes have been stripped at some point so that’ll need a new one.
Diff carrier out in preparation for a rebuild with new bearings and clutches. Going to go with the existing ratio of 3.36:1 which will give 177mph at 7500, so a bit on the long side but we’ll see.
Case cleaned and painted. First shiny bit completed instead of disassembling rusty crap.
Oneball
CCCUK Member
It’s just the cover that’s stripped. The diff itself I’m rebuilding with a 400lb spring and 22 plates and uprated output shafts. Will also tap the case for a cooler.
To my knowledge the only difference between big block and small block diffs is the output shafts.
Correct but GM had the bolt in caps for a reason. I too have a diff cooler set up.
Dazaa
Well-known user
Why not Helicoil the diff case? I just did 2 of the sump bolt holes on my TH400 and it took about 10 minutes!
Also how difficult a job is rebuilding the diff? I know mine leaks and will need a rebuild soon but i'm worried if I pull it apart it'll never go back together right.
Also how difficult a job is rebuilding the diff? I know mine leaks and will need a rebuild soon but i'm worried if I pull it apart it'll never go back together right.
Oneball
CCCUK Member
If it was just a sump retainer I’d Helicoil but it’s a couple of the holes that hold the diff to the crossmember and therefore hold the suspension to the car, not worth the risk in my opinion. The rear cover isn’t too expensive anyway.
If it’s just leaks, it’s relative easy to change seals. Rebuild is a bit harder as you need to set the lash/tooth interface between the crown wheel and pinion. That requires use of a dial gauge, engineering blue and often multiple assembly/strip downs. Not hard if you follow the procedure but a bit of a faff.
If it’s just leaks, it’s relative easy to change seals. Rebuild is a bit harder as you need to set the lash/tooth interface between the crown wheel and pinion. That requires use of a dial gauge, engineering blue and often multiple assembly/strip downs. Not hard if you follow the procedure but a bit of a faff.
Dazaa
Well-known user
ah I see, I wouldn't helicoil the mounting holes either, thought it was just the cover bolts.
It appears to have a small leak on both sides so I guess it's a full rebuild or is it just a seal?
Oneball
CCCUK Member
Gearbox strip down today.
Sidecover off, two of the threads are buggered so they’ll need helicoils.
The selector forks are worn, especially for 4th so new ones of those to the list.
Extension off and gears out, reverse fork also needs changing.
I’m changing the gearset from the M20 that’s in there to an M22 so most of this is useless.
The only bit that could have been reused is reverse gear but that’s trashed too.
Time to give the cases a proper clean and order a load of bits.
Sidecover off, two of the threads are buggered so they’ll need helicoils.
The selector forks are worn, especially for 4th so new ones of those to the list.
Extension off and gears out, reverse fork also needs changing.
I’m changing the gearset from the M20 that’s in there to an M22 so most of this is useless.
The only bit that could have been reused is reverse gear but that’s trashed too.
Time to give the cases a proper clean and order a load of bits.
