95' Junker Drag Truck

AsTroSS said:
For me it looks like crack in input shaft , near the hole ...
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Yeah, I saw that when I posted the pictures this morning. When I get home tonight, that's the first thing I'm going to look at. I'm guessing it's just a piece of debris that looks like a crack, but if it's a crack..... :woohoo: ..... I finally made enough power to break a stock input shaft!
 
Carnage Update!!

I did in-fact crack the factory input shaft. Finally this truck made enough horsepower to break the "known" weak link. I can't say that I was overly abusive with the lock-up switch except when running at the drag strip where I would command lock-up at the very bottom of second gear where converter stall was it's highest so RPM drop shock load was extremely high.

I was digging through my box of time slips and this stock transmission shaft has endured over 130 1/4 mile passes and probably all 241,000 miles on the truck's odometer.

Only one side of the shaft is cracked, luckily the forward clutch pack failed before this factory stock input shaft let go, who knows what it would/could have taken out.


I would like to hear opinions if this is likely the cause of my 45 psi pressure dip during lock-up engagement or not? The cracks don't appear to go further than the edge of the seals but I don't know if there are hairline cracks that extend further that open up a little when the shaft is loaded.

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do you need another stocker to get you by? i have one sitting at home i can send out for free
 
I appreciate the stock shaft offers, but I think I'm going with an aftermarket billet input shaft. I feel lucky that this shaft didn't leave me stranded or with other broken parts so no sense in tempting fate twice and running another stock shaft.
 
Wow you are lucky it cracked like that and didn't break clean. Looks like if you were giving it just a hair more juice at the time it cracked, you wouldn't have been so lucky. Its amazing what yours took before she let go.

Sent from my phone, probably while driving, so please excuse the typos.
 
Below are a few pictures of the "new to me" used billet input shaft that arrived in the mail yesterday. It's a little twisted but the price was right...... FREE. Thank you Phil Taylor from Diesel Performance Converters!

Now for pictures of the shaft, it looks like a Precision Industries shaft but I haven't confirmed with Phil where it came from. It's a one-piece shaft and it looks to be in great shape on all of the bearing/bushing surfaces. I did notice that it has a little thicker shaft: larger outside diameter and smaller internal hollow converter lock-up feed passage. It is also quite a bit thicker on the converter lock-up feed hole portion of the shaft, this is the same location that broke on my stock input shaft.

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The inside diameter of the billet shaft is smaller than the stock shaft. This leaves more steel in the shaft to prevent twisting and breakage.


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Just read this entire thread... Awesome to say the least. Keep up the good work. I would petition harbor freight for a sponsorship. Judging by there ads in upscale magazines like playboy (so I've been told) I'd say they have a few bucks dedicated to marketing.

Any updates on the truck?
 
AIRticulated said:
Just read this entire thread... Awesome to say the least. Keep up the good work. I would petition harbor freight for a sponsorship. Judging by there ads in upscale magazines like playboy (so I've been told) I'd say they have a few bucks dedicated to marketing.

Any updates on the truck?
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There's something wrong with that post.


THis is CompD, admitting that you have a Playboy subscription will not even muster a blink from the readers...
 
LOL!! Hey Big Blue, doesn't that twisted shaft worry you that it's gonna let go? Or not? Also, I too would like to hear if this takes care of your pressure drop when locked, as my pressure drops at least 10 psi when I hit lockup. I've got a brand new Sonnax 1 piece, but I'm wondering about my stator support bushing.
 
deerefanatic said:
LOL!! Hey Big Blue, doesn't that twisted shaft worry you that it's gonna let go? Or not? Also, I too would like to hear if this takes care of your pressure drop when locked, as my pressure drops at least 10 psi when I hit lockup. I've got a brand new Sonnax 1 piece, but I'm wondering about my stator support bushing.
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I won't know if this shaft will hold up till I try it. If it lasted a few low 9 second passes in Phil Taylor's truck with just a minor twist, I'm sure it will hold up to my truck for a while.

I personally would expect a 10-20 psi momentary drop during lock-up because line pressure has to fill/pressurize the torque converter lock-up piston.

The two small seals next to the hole are what retain the lock-up pressure. If the lower seal is bad, the stator support bushing would likely help retain pressure as well. If the upper seal is not sealing properly, it will bleed lock-up pressure into fluid coupling portion of the torque converter flow circuit so in that case, the stator bushing would not help. Since you have to pull the pump to replace the input shaft, you should inspect the the large bushing that seals against the torque converter snout to see if it snugly fits the torque converter, if not, you should change it since it will definitely lower pump flow and pressure.
 
Mine wasnt twisted that much! nice find though, should hold up alright at your power level.
 
ive been looking at your thread and videos all day..impressed to say the least. im considering putting an 88 beside my he351 instead of an s366 on my cr now
 
She's alive!

Yesterday afternoon I finally got the Junker put back together. The new input shaft did the trick, line pressure drop during lock-up is just 10-15 psi and it quickly ramps back to pre lock-up pressure.

Cruising in 3rd, line pressure is running 185 psi. Cruising in overdrive unlocked, line pressure is running 205 psi. WOT in overdrive unlocked, line pressure ramps up to about 215-218 psi. WOT in overdrive with the converter locked 200 psi, and a huge grin on my face!

I rolled into in 3rd locked with the windows down and at 80 MPH, there is a definitely loud screech from the rear tires. Might be the cooler weather, but it feels like it's pulling harder than it ever has in the past.

I double checked at 65 MPH, it can definitely turn over these smooth 285/75/16's aired down to 25 psi. It'll spin so hard I have to lift because it goes sideways as the white smoke rolls out of the fenderwells.... lots of fun.
 
Dec 2nd and Dec 9th are the last two street legal track nights this season.

I acquired some MT ET Drag 29.5 x 11.50 slicks a few weeks ago, unfortunately, they don't allow slicks on the street legal night.

I have a buddy with some MT 29x18.50 D.O.T. drag tires, however, they require 14" wide rims and cheap steel wagon wheels 8 lug 15 x 14 run $266 for a set. I might entertain that price if it they were light weight aluminum, but not heavy steel.
 
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