Dragaholic

iTrader: (180)

We started the gear swap a couple of days ago only to discover that there were 4 broken teeth on the ring gear and couple on the pinion. We had to slide the rear end back because the driveshaft wouldn't slide far enough forward to remove from the rear end. After inspecting it, we also found that it was twisted inside.

I called Denny's Driveshaft, as we have one of their nitrous ready shafts, and they explained to me that the twisted slip yolk was due to the broken gear. It's that momentary bind that will cause a slip yolk to twist. He also stated that it's very rare that he has customers send back a twisted yolk, maybe 4-5 a year and it's always due to a broken gear.

Anyhow, how does something like this happen? We were already planning on swapping the gear anyway because we had too much, not making it to the end of the track. We have a Strange 12 bolt, narrowed 3" per side, spool, 4.56 gear (swapping to 4.11), aluminum support cover, etc. Again, we have a chromoly nitrous ready Denny's Driveshaft with a 1350 slip yolk.

I heard a noise last time out and it was coming from the rear of the car, so definitely what I was hearing came from that broken gear. I haven't even hooked yet, so I'm confused on how it happen. Last time I was out, I cut a best of a 1.888 60 ft. (spun bad) and it usually runs in the mid 1.30s. Heck, with the new setup, it should be good for low 1.30s. If I break another gear, I'm going to twist another slip yolk. What to do?

csjta2

iTrader: (43)

What kind of gear in the rear?

Standard or Pro?

Dragaholic

iTrader: (180)

Their standard is called Pro Street, their "premium gear is called Competition. The Pro Street is for street use and the Competition is for drag race. Supposedly the Competion (drag racing) is a softer metal, to absorb more shock. I have their standard (Pro Street) gear.

WickEdSix98

iTrader: (4)

As quick as your car is, you should have been running the Pro gear already. The street gears will continue to break over and over.

Dragaholic

iTrader: (180)

I went ahead and placed another order for the Competition (Drag Racing) gears. I decided to play it safe.

Important question: If I replace the slip yolk, do I need to rebalance it?

RAGENZ28

iTrader: (5)

I ran a 12 bolt with 33 spline strange axles and went a best of 1.30 60ft, I ran a Pro Gear and also street drove it and never had any problems.

Sorry about the bad luck hope you get it running and working for you soon.

I recently had to replace a cracked slip yoke on my lady's ride. I just swapped the yoke. I would swap it and run it and test drive it and see if you get any vibration.

I didn't get any vibration after I swapped the yoke and I ran it up to 100 mph and didn't notice a thing.

FASTFATBOY

iTrader: (23)

You dont need a "pro gear" at your level.


If the car wheel hopped AT ALL that is what got it. 12 bolts do not like wheel hop.


Wanna trade rear ends?


David

TXCAMSS

iTrader: (60)

You are leaving the line at over 6000rpm off the t-brake with a street gear pushing some serious HP. You found the weak link. I would footbraked the car to get the proper stall and shift extension data rather than launch it like that. That's just me.

Again..The true stall of the TC could have been determined by engaging the TB in place and watching it for a few seconds on the tach (no harm done) or data logging it during that time.

It might have happened anyway, but ......................

CutlassRacer

I have run street gears deep into the 8 second zone, without failure.

That being said, the 12 bolt does not have the best spacing for the ring gear in that the gear ends up being pretty thin on the lower (numerically) gears. We run a 3.73 in a low 9 second Nova (that got 3rd at the Pump Gas Drags last year) and we inspect the gears regularly to look for cracks.

Dragaholic

iTrader: (180)

FASTFATBOY, what level are you referring to? Don't be confused with my old cam only setup. The car does not wheel hop. I haven't even gotten the best of traction yet with the new setup, so it makes me wonder how the heck it broke.

TXCAMSS, I think you're right. Transbrake, high stall, etc., then bam! I don't want to back off the launch though just so that I don't "hurt" the drivetrain. I want to leave as hard as possible. I wouldn't say serious HP. So are you saying that I won't get good data if I transbrake the car vs. footbraking it? The next time I'm out, I'll have my Autometer Ultimate II tach in, that has data logging and is dual channel to record driveshaft speed. Once I get some hard data, I will pass that along to Joe at Protorque so he can properly set up my converter. If I watched the rpms while just sitting there on the brake, I would definitely need an aftermarket tach because the stock one we all know is off.

CutlassRacer, I was thinking the higher (numerically) gears were weaker being they have more teeth, giving them less material. The lower (numerically) gears would have less teeth which should give them more material. I may have it all wrong, that's just my guess.

FASTFATBOY

iTrader: (23)

DId you consider my offer on the rear end swap?

Moser 9 inch

Narrowed 3 inches per side

31 spline axles

Nodular center section

Detroit locker

4.11 gear

5/8 studs

LCA relocation brackets

Extra(lower hole) shock mounts.

FIll welded in top

Big Truck yoke

Vent moved to axle tube so it dont puke oil like ALL 9 inch rear ends do.

You would have to install a GOOD posi unit and a street gear in yours for me to swap.

TXCAMSS

iTrader: (60)

I would get some one to loan you their HPT stand alone data logger for a single pass. I'll loan you mine if I'm there and I'll set it up for you. Then you can start logging,engage the TB and go WOT on the brake for a few seconds. That'll give you your true stall. Then make a pass off the foot brake rolling it out pretty good and see what the shift extentions are and what MPH the car is capable of.

The point is, your cam only TC was probably a very high STR (at least a 2.5) because you had pretty low TQ,but now you have an abundance of TQ. Say you have 600rwhp/600ftlbs of TQ at now and an STR of 2.5, in theory that has you leaving the line with 1500rwhp/rwtq. I hope that makes sense.

Dragaholic

iTrader: (180)

FASTFATBOY, I have no reason to swap rears. I'm not even sure why you want to trade. My rear end has a spool and will have a 4.11 gear.

TXCAMSS, I don't know of anyone off hand that has HPT. I would have to ask around, but if next time I'm out and you're there, and of course if you don't mind, setting yours up in my car would be awesome. I understand exactly what you're talking about. STR = stall torque ratio