I just had my 4.56's replaced with 4.10's and my rearend builder called me and was like "these gears (the 4.56's) are already trashed man". He showed them to me when I picked up the rearend and I asked him what caused it and all he could figure from looking at them was too much power. I thought this was kindof strange given what I run but who knows. The best way to describe what the gear looked like is this. On the teeth of both the ring gear and the pinion you can always see the normal wear pattern as it is shiny. The gears had this shiny wear pattern, but in the middle of this shiny pattern on all the teeth (both ring and pinion) there was a black (looks burnt) patch running long ways with the teeth. I hope I'm explaining this right??? Does this sound right to yall? I don't know much about setting up gears, so I don't know. I literally had only 9 passes on these gears and thats it. They were GM gears, not that cheap **** either.

My next concern is that this guy maybe wanted my good used 4.56's for his own benefit and showed me another set that had been torn up. I don't know. Doesn't seem to me that I'm at that power level yet that I have to worry about this. Or am I?

 

So you had no break in since there were no street miles? If so, you ruined them because you didnt break them in properly.

Your supposed to drive on them very easy for several hundred miles then slowly get on it and break them in/

 

yeah you should have broken them in

 

break-in really depends on how they were setup... I always set mine up on the tight-side so I do break them in a good bit and put fresh fluid in the rear before I really beat on them. setting them up looser normally requires less break-in...

I think its really subjective. I've seen people throw a brand new ring and pinion in at the rack on jack stands, go make passes with them, and get years of use.... there's really no rhyme or reason to me. I hope you get better service out of your new ones. My GM 3.73's have held up very well setup at .005" backlash. How he set pinion depth will also determine how the pinion "climbs" the ring gear (since in affect, this is what happens) if its too deep it will sometimes cause those hotspots on the ring gear.

 

In my dirt track car I only have a few laps of easy break in until i go wot..thats 6.00 in a 9 in

 

What about race cars that don't see any street use at all, how do those gears get broken in? And shouldn't factory gears be good to go since they are heat treated anyway? Not arguing, just asking...

 

Mine looked fine, my break in was 5 heat cycles, 1 good burnout, and changed the fluid after about 500 miles.

 

Yep,Need a few heat cycles and a few hundred miles before dropping the hammer on them regardless of brand name.More than likely they overheated and got damaged before they got cured to take the abuse.Installation setup is very important also.

 

Ben, so are u sayin u setup your rearend, & add new fluid. Break them in, then change out fluid that may've only been there for a bit, say 500 miles (whatever, pick a #) before beatin on it & then swap that for brand new fluid?

Or did u just mean add fresh fluid when doin rear, take it easy, then thrash on it? Cause this is what I'm thinkin. I prolly just read into it too much.


I read what u had done then said, well it sounds like it doesn't have that much power for 540+. Then I saw the High 10 ET, reread to see a Procharger. It didn't stick out the 1st read
So that's how u were gettin 540+. Anyway, if he's your rearend builder & u think it's possible he wanted your 4.56's himself, find a new builder. Trust is huge. Myself, if I didn't see him pull em out after 9 passes, then I'm noy goin to rule that outta the question.

Even if I had a "track only" car, & I could put my trailer (if I had 1), right next to track, wheel it off, then flog it. I wouldn't, back that's just me. Myself, even on a strip only, I'd find a way to get a few gentle "breakin" miles on the gears.

 

Did you not like the 4.56s? What size tire are you running?