Can you say ‘shock load’ - both spider gears broken in two pieces with the teeth in tact is a dead giveaway.
I’m confident the wheel hop got ya.
I’m confident the wheel hop got ya.
BUILD THREAD 86 GP 2+2~Blown 6.0
- Thread starter 81cutlass
- Start date
Yeah I'm going to agree with you there.
Lesson learned, if you start to feel wheel hop in the burnout box, don't try to power through it. Abort and ask for a bit more water or back in more and get the tires fully wet.
A set of stiffer shocks is in the cards too. Kyb are good street shocks on a budget but are too soft for a real drag car.
Lesson learned, if you start to feel wheel hop in the burnout box, don't try to power through it. Abort and ask for a bit more water or back in more and get the tires fully wet.
A set of stiffer shocks is in the cards too. Kyb are good street shocks on a budget but are too soft for a real drag car.
I'd skip right past the 8.8 ford since an 8.5 GM is the same thing. It's a side step with no real improvement.
At my former employer the manager of the group next to me was a former program engineer at Ford on the 8.8 product line. He said internal to Ford that rear was considered an 8.5 if it went into a car (panther/fox) or a 8.8 if it went into a truck/suv (exploder/f150). They were the same ring/pinion they just called them different names to keep the 28 spline car and 31 spline truck/suv stuff separate.
In my opinion, the only reason the 8.8 ford is a common performance rear end these days rather than the 8.5 GM is that it actually got put in 5 lug applications and the Fox chassis. Ford was smart and put the 8.8 in explorers and fox bodies whereas GM put the 7.5 in S10's, and F/G bodies.
I assume the GM bean counters were more stingy in the 80's than ford and decided to save the $7 per vehicle to put the 7.5" in everything rather than the 8.5. Ford had the 7.5" in Rangers and 4/6 cylinder fox bodies but put the 8.8 in everything pretty liberally. The 8.5 GM was a RARE upgrade in GM (GN/442 and stick 4.3 s10) whereas the 8.8 was standard in the exploders and easily optioned in the fox.
The 8.8 also has some benefits in that it came stock with 31 splines in exploders with a clutch style posi whereas GM stopped at 30 spline with gov bombs. You can put a 30 spline used clutch style posi diff out of a mid 90's caprice into your 2nd gen f body or G body 8.5 BUT again, more B bodies came with 7.5's and if they did come with 8.5's they were often 2.73 rear gears and nobody wants to reshim their rear.
The 12 bolt GM, 8.5 GM and 8.8 Ford are all the same thing from everything I have seen.
The 9" hasn't ended up in a junk yard in 10 years so everything is bent, overpriced, or all new expensive aftermarket. Nobody is dumping nodular iron 9" 31 spine center sections in the yard anymore.
It's my opinion that the 9" ford is like the SBC. It was the best thing in it's day but it's really dried up. LS and 8.8 have overtaken as the new 'standard' and the SBC and 9" are still popular today mostly from inertia. I can dump $2500 into a 9" for all new stuff or get lucky and find a 3.73 31 spline N case 9" center section with a good posi for a good price (not going to happen).
A 14 bolt 9.5 has a more efficient gear mesh than a 9", has factory 33 spline axles and a clutch posi factory and are available in yards in good numbers. People moved from the SBC to the LS because it's a better design. I fully agree the aftermarket for the 14 bolt SF 9.5 isn't fantastic, but it has a lot of great features on paper that I would like to utilize.
If an 8.5 is what you want, why not a 2wd truck axle? I forget the spline count there, was it 28 then 30?
GM went from 28 spline to 30 spline in 89 I think on the 8.5.
This rear started out life as a truck 8.5 30 spline. It was a 97 S10 zr2 rear that I cut the tubes off and replaced with 7.5 tubes. Could have started with a 94 1500 suburban, 02 1500 sierra, or 77 trans am for what I did since I ended up scrapping the factory axle shafts and diff. Only reason I went zr2 is they had the same rear disks as the 2wd blazer swap everyone does minus the rotor offset. $100 for the gear set, disk setup, and pumpkin section was worth it to me.
I turned OD of the 7.5 tubes down about 0.020" so that they were the same as the ID of the 8.5 rear and then pressed the tubes in and welded them in. I bolted the zr2 s10 rear disks onto the G body tubes and replaced the axles with moser 30 spline GN replacement axles and that Yukon posi.
Essentially this rear should go 9's no problem but when you have 10's power and a stick (and random dry water boxes) it breaks stuff.
Ya win some and ya loose some.
This rear started out life as a truck 8.5 30 spline. It was a 97 S10 zr2 rear that I cut the tubes off and replaced with 7.5 tubes. Could have started with a 94 1500 suburban, 02 1500 sierra, or 77 trans am for what I did since I ended up scrapping the factory axle shafts and diff. Only reason I went zr2 is they had the same rear disks as the 2wd blazer swap everyone does minus the rotor offset. $100 for the gear set, disk setup, and pumpkin section was worth it to me.
I turned OD of the 7.5 tubes down about 0.020" so that they were the same as the ID of the 8.5 rear and then pressed the tubes in and welded them in. I bolted the zr2 s10 rear disks onto the G body tubes and replaced the axles with moser 30 spline GN replacement axles and that Yukon posi.
Essentially this rear should go 9's no problem but when you have 10's power and a stick (and random dry water boxes) it breaks stuff.
Ya win some and ya loose some.
The stock 31 spline 8.8 axles have more than just 1 additional spline than the GM 8.5/8.6 30 spline. The axle itself is larger diameter from the spline to the flange than the stock 30 spline GM. The aftermarket resolved this - a 30 spline Moser is a chunk in comparison to the stock GM 30 spline which can also be considered a chunk in comparison to the GN/442 28 spline. And then compare the stock GN/442 28 spline to the stock 26 spline 7.5 rear that was stock and you'll see why the weak link in the 7.5 is the axle. I have a set of each on the property and it's literally night and day. Ford got it right, I hate to admit, with the 8.8 31 spline diff. Lastly, the 8.8 ring gear is a much heavier gear than the GM equivalent - at least for a 3.73.
The equalizer between the GM corporate 8.5/8.6 is an aftermarket axle which will set you back $250-275 depending on where you buy them.
Absolutely, the 8.8 exploder rear is much better than a 28 spline GN 8.5. I have the 30 spline moser set in mine and they even look boarder line insufficient. I assume ford went 31 spline in the exploder 8.8 since they had 31 spline tooling from the 9" days whereas i don't think GM ever had anything about 30 in the 12 bolt so we got stuck there. I've never seen a factory 28 spline 8.5 axle but I've looked at 26 spline 7.5 stuff compared to my 30 spline moser stuff it's comical how tiny the 26 stuff is.
I've never taken apart a 8.8 to be honest so I can't compare the gear width but I don't think 8.5s have a softer pro gear available but I know 8.8 does.
It's odd how gm deciding to make the 12 bolt 30 spline in the 1962 but ford decided to make the 9" in 57 up to 31 spline and we are still living with the reprocussions today.
In other news I swapped my front skinnies for my 17's and pulled the broken carrier and prepped for the truetrac.
When the gears broke it bulged the case and I had a heck of a time getting the ring gear off. It split the case axially through the lock bolt hole.
I remembered watching Mike's 'brown pants' video that my gopro was on this pass.
It made it about 20ft before it popped. You can see the wheel hop 'shake' for about 1-1.5 seconds before I powered out of it.
It made it about 20ft before it popped. You can see the wheel hop 'shake' for about 1-1.5 seconds before I powered out of it.
