BadAss SRT-Z - 2.4L / A568 - Update!!!

[BadAssPerformance]

Jt not to stir the pot, but are you sure it is spark plug problems and not standalone/ mechanical problems.

Good question. I was questioning the coil since that was the other thing I changed when chasing last years issue which turnout out to be the cam sensor. But for now at least, the plugs seem to work, but really need more testing than the couple runs on them to know for sure.

FYI, and you probably know this, but 4306's will not work in early 2.4l's. Early 2.4's take gasket-seat plugs. Later ones (01-up) take tapered seat plugs.

Good to know, I only have the older head and was wondering why SRT4 folks were suggesting those, LOL

[BadAssPerformance]

Update on trans...

So took it most the way apart and the pinion and ring gear were both missing teeth. The last time this happened I wrote if off as a chipped pinion tooth (that I knew about) finally coming off. This time all the teeth were good going in, so maybe case flex helped them come off? Also I think the case split this time cuz a tooth got caught between the ring gear and case, maybe the taller ring gear of the 3.85 vs the 3.50 helped that?

I'm cleaning up another 568 to go in and thinking about welding on some bracing, but not sure where I want to put it. Really don't want to add too much rigidity to one are and put all the stress to another area to make it worse. Might just put it in without bracing and try to GoPro it and see if the flexing is visible

[135sohc]

That would have to be a lot of flexing to see it without some sort of strain gauges mounted on there ?

[BadAssPerformance]

True... I'm wondering how much it would have to be to cause shallower tooth engagement to let them break?

[Vigo]

I dont know how much time you are ok spending swapping transmissions out but if it were me i would probably be trying to build a tunable clutch release setup and then seeing if i EVER broke another transmission once the launch was truly controlled. I am guessing all this damage is coming from clutch release primarily. Momentary stresses are fatiguing the aluminum in the case and as it fatigues more and more it may actually fail at a lower stress moment like in 1st or 2nd or during a shift. Just like if someone manages to throw a rod at 5000 rpm it was probably because of 8500 rpm some previous time. I have felt what loose teeth going through a diff feels like and if there were foreign objects floating around in there BEFORE the case started breaking i think you would know it. My guess is teeth are breaking AS the case is splitting from fatigue unless you somehow know for a fact that the broken teeth came first..? There are a lot of pages in this thread so i might have missed that part..

[BadAssPerformance]

Good question on which broke first, the teeth or the case. I was thinking teeth cuz there are several cracks in different directions and case was cracked straight through the diff cover, meaning line of crack thru case and diff cover. Pics on FB I'll add them here later. I could be talked into the case breaking first tho... hard to say.

I agree, the root cause regardless of case or teeth is fatigue from some heavy hits. I'm not really surprised or upset at all that it broke and expected it to sooner or later. This trans was on borrowed hopes and dreams really... it went in 2 years ago and lived through all of the hits on the 26's

[BadAssPerformance]

After some good quality time dissecting 3 transaxles (broke one, new A568 and an a523 to grab ring-pinion out of) it went around the block last night shifting through 5 gears plus reverse of the new frankentrans...

When the last trans went in almost 2 years ago I picked upa spare A568 from Jackson. Although it was oily it has seen some WI winters and was a tad corroded. A couple cans of brake cleaner, paper towels, wire wheel, it looks decent. I decided not to weld any bracing on thinking that the recent failure was tooth decay... Wanted to keep teh 3.85 gear and was planning was to use a Quaif but the axles didnt seem to fit right (story later) so I also dug into a spare A523 that was bought for the ring/pinion.

Parts from broke trans:
TOB
clutch fork/lever/bushings
shifter housing
DS diff bearing retainer
shift cable bracket
trans mount bracket

Parts from A523 (the pinion bearing was going and the trans looked rough inside but input shaft looked new and speed gears decent if anyoen needs any LMK):
main/intermediate (pinion) shaft
ring gear

New Parts:
OBX diff (new batch of these things looks better and fits better too.
diff bearings & seals
input shaft bearings & seal
pinion bearing (the one that is a real MF to get off the shaft)
lengel pads on 1-2 & 3-4

Also while apart, changed oil, new plugs (same AutoLites gap 0.23"), adjusted tune a little to try to idle better (no AIS on this car) plun some new skinnies after finding a couple flat spots one down to cords

Also removed 2-stage boost control because it would not go lower than 35psi on high setting an put single stage 29psi setup back in...

Hoping it runs well thsi weekend in Norwalk! A win thsi weekend is being able to drive back on the trailer LOL

[Reeves]

Woot woot!

[contraption22]

Good luck!

[jonnymopar]

Good stuff right there JT!

...Wanted to keep teh 3.85 gear and was planning was to use a Quaif but the axles didnt seem to fit right (story later)

Curious about this since everything I've read makes it sound like the Quaife is the holy grail of LSDs.

OBX diff (new batch of these things looks better and fits better too.

I am even more curious about this after finding the issue with the direction of the gear teeth. I would love to see a very recent unit disassembled. Obviously it wouldn't be yours since it's already in. What about it looked better/fit better?

[turboshad]

I took these for you the other day JT, just forgot to post them. This is what I have for my clutch switch.



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[85glht]

I decided not to weld any bracing on thinking that the recent failure was tooth decay...

Maybe the oil you are using in the transmission isn't doing its job. Heavy car, lots of power, you might be shearing the oil clean off of the teeth causing excessive friction. Ran into this problem on a friends car.... Chysler 300 with a 540 ci Keith Black engine, car was 4800 lbs, made 900 hp with a lenco transmission. The car had a Dana 60 for a rear end. After a few passes, the rear end made weird noises. We took the cover off and the gears looked like they were machining themselves into oblivion. My friend then used an oil from Torco Oils. It did help the situation. I know it sounds extreme but it could be happening to you. Good luck in Norwalk!

[GLHS60]

DJ, can you post the picture again or the link to the screen door hydraulic clutch engagement system you posted a while back.
It seemed like a neat idea, did you ever try in out?

Thanks
Randy

I took these for you the other day JT, just forgot to post them. This is what I have for my clutch switch.



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[turboshad]

DJ, can you post the picture again or the link to the screen door hydraulic clutch engagement system you posted a while back.
It seemed like a neat idea, did you ever try in out?

Thanks
Randy

No I didn't try it Randy, it's a little bit too hillbilly for me. I prefer a more engineered and intentional purpose built approach.

http://grannys.tripod.com/hillbillyclutchslipper.html

[Rrider]

That is a great idea whoever thought of that.

http://www.ebay.com/itm/like/190836928447?lpid=82

These might be worth a try. They go from $20 to Ohlins.

[GLHS60]

I appreciate the link DJ, I know your certainly more Hill William, than Hill Billys like me, but its still a neat idea!!!

Thanks
Randy

No I didn't try it Randy, it's a little bit too hillbilly for me. I prefer a more engineered and intentional purpose built approach.

http://grannys.tripod.com/hillbillyclutchslipper.html

[Reeves]

Hill William! Love it.

[Ondonti]

I just wish the picture attachments were a little less hillbilly. I still don't know what the transmission looked like

[jckrieger]

I'm guessing no matter what you do to the case you're still going to see similar failure modes. The used transmissions all have accumulated plenty of fatigue damage over the years of use, so failure is likely going to be inevitable. Why not go with a more modern 2.4L transmission? Maybe a low miles SRT4 trans? At your power levels, even HD transmissions like a T56 can die given enough miles/torque.

[83scamp]

I'm guessing no matter what you do to the case you're still going to see similar failure modes. The used transmissions all have accumulated plenty of fatigue damage over the years of use, so failure is likely going to be inevitable. Why not go with a more modern 2.4L transmission? Maybe a low miles SRT4 trans? At your power levels, even HD transmissions like a T56 can die given enough miles/torque.

Because they are junk. The SRT guys want our trans because they live longer...