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Broken input shaft? help please... Trannyman?

C

carfreak967

New member
Hello, this is my first post, but ive been lurking for a while..:th_thumbsup-wink:

so, heres my situation. i have a 99 regal GS, gen V intercooled 3.0" setup with 1.9 rockers, injectors, northstar TB headers... etc

so around november my 170k mile origonal transmission decided to start whining and slipping really bad... wouldnt even move. so i figured it was time to replace...

i found a 3000 original mile trans with the 35/35 gearset and swapped the diff and diff cover from my old trans into it for the 3.29 gearing.

now, only 4 months later, and only 5k miles of driving.. i think it broke :th_shakinghead1:

to be honest, i was pretty damn proud of myself for putting it in by my self in the first place, and am pretty devistated that it broke only 4 months later...


ive been told that it might be an input shaft.... what happened was i was getting on the gas pretty hard going into WOT, but, i was going about 40% throttle... so the trans was getting ready to shift into 2nd.... i didnt know this, but when i got on it, the trans seemed to already have its mind made up that it was getting ready for 2nd gear... this has happened a few times, i dont like it. its like, it slips then kinda grabs into 2nd gear... i wish i could figure out how to fix this. but it seems that with my new setup its more likely to happen

both my old and new trans seem to start shifting kinda long in advance, this is pretty much how i end up flooring it when its shifting into 2nd... no matter how careful i am...

so when it grabbed 2nd gear kinda hard, it quickly went into a neutral-like state. and literally, every gear, D, 3, 2, 1 are all exactly like Neutral...

no funny noises, no leaking fluids. nothing. its like i just lost my gears. its constantly neutral


could this be an input shaft?


whatever it is, i really need to fix it cheap. i have my old trans sitting on my front porch (yea... were a little redneck sometimes). so i could always swap my old input shaft in i suppose.. but i really dont need to be dealing with this now :th_depressed:

so, my question is: does this sound like an input shaft?

and if so, how hard is it to replace this input shaft? would another stock one be okay, or should i upgrade?

and finally... how the hell do i stop this scenario from happening again? it seems like i cant get my shift just... FAST, it starts shifting.. its always slower than i want it to be, then grabs the next gear hard at the end.


all i have is the ZZP "recommended" spacers in the accumulator, and my tq management is reduced about.... 20% lower than stock perhaps...


sorry for the long rant.. lol, im just really looking for answers... i need to fix this thing as fast as possible. so any help would be great

and if anybody knows how i can stop this long, drawn out 1-2 upshifts from happening... please let me know... i was planning on adding a 2-3 shift spring in the 1-2 slot?

and hopefully somebody can shine some light on my problem... need this thing fixed asap

thanks so much in advance, and for reading my long-winded explaination...

-Ryan
 


Get a better shift kit, and someone who knows how to work with it in the tune. The Intense shift kit in my tranny makes all the shifts quick and crisp without being jarring. Should keep harsh jolts from going through the tranny.

Trannyman will probably tell you to just upgrade the input shaft, which is what I'm thinking too. At that mod level you're in the area where your stock input shaft and chain can become weak points.
 
what is a better shift kit? from what im thinking, that 1-2 spring is too soft, so it slips, then grabs when it hits the spacer

my theory is the 2-3 spring for the 1-2 shift will make it firmer from start to finish... is this true?

i honestly think that this was the cause of the broken input shaft. the engine revved a little and got a chance to take a running start at my tranny... and screwed me over

so im trying to find a cheap upgraded input shaft.... is the cheapest one $350? geez... and if i wanted to swap a stronger chain.. like a 7/8ths, where can i find one of these?

and how can i find a write up on replacing just the input shaft? and if im replacing the input shaft, is the chain right there, or is it harder to replace the chain?


thanks!
 
ok, so im reading up on this stuff now. it looks like im going to have to make that choice. the question is weather i can afford beefed up parts like that right now. at least this trans has 7k miles on it, so most of the clutches should be in good shape. it also came out of a 2002 regal ls.

id say if i was going to spend the money on a shaft, i might as well spend the cash on a chain too, so ill have to see if i can afford $700 right now... thats gonna be a tough one

and for my other question... does putting the 2-3 spring in the 1-2 accumulator spot help? whats it feel like? i have DHP powertuner, so maybe somebody can help me stop this sloppy-then-hard shift, and turn it into a smoother quicker shift

thanks

BTW, any info on any special tools and stuff im going to need would be greatly appreciated, im really trying to get a good idea of whats in store for me
 
ok, just an update

the zzp shift kit i have, braggs about how good their instructions are. now my friend and i are not dumb, and we both did not gather that we were supposed to install spacers BELOW the piston, between the piston and housing....

so i only have 2 spacers installed in my accumulator, and they are on top of the piston, sitting inside the 1" diameter springs....

so, does anybody know if this has anything to do with my not-so-quick upshifts? perhaps spacers on top of the piston quicken downshifts, and spacers below the pistons quicken upshifts? because my downshifts got better after this kit, the upshifts... not so much

thanks!
 


It definately sounds like you broke your input shaft especially since you dont have any noise while reving it in gear. One way to verify this is to watch the "Trans Input Speed" signal with your PT scanner if you have that available to scan. If there is little to no rpm signal then your input shaft is broke, if you show rpm that is in close relation to the engine rpm then your chain snapped but I would lean more towards the input shaft. Your cheapest option for an upgrade is the 4340 shaft from ZZP and that should work ok for your setup but I would spend the extra money and get either the Intense shaft or the 300M shaft from ZZP as they are both much more durable. At your level I wouldnt worry about a single chain upgrade but it would definately be a good idea to swap in the dual replacement chain set from the V8 cars which is stronger. I sell these chain sets for $69.95. As far as the shift kit goes the Intense kit is definately the most complete one available and will work better for you. It includes heavier springs which are much needed as well as a number of selective shims and spacers so take Sabrewings advice on this one, you wont be dissappointed. Also the tune has a large effect on shift feel so it would be a good idea to talk to someone with a powertuner to help you out or get some advice. I use HPTuner and things are set up a little different so I cant give you direct examples to use. I have a writeup on here somewhere for a gear ratio swap which entails replacing the chain sprockets and the reassembly of the channel plate and valve body as well as torque specs. You must also make sure your pcm is properly set up for 3.29 gearing as stock it had 2.93 and this will throw an incorrect gear ratio code and cause a number of problems. You may not have your shift mph and timing tables set up properly for the 3.29 gearing so that may be adding to your odd shift behavior.
 
Yep I have been using them for a while as my distributor only stocks that chain and has since it was available so all of my high perf rebuilds with dual chains get a new 093 V8 chain set.
 


Dave, thanks for the info. i have a stock GT trans file on my car. so the shift points are correct. its been modified in terms of line pressure and its commanded shift point is 5900rpm.

this "odd" shift behavior happened on my old trans after my gen V northstar intercooled setup too. it feels like i simply went WOT when it was in the middle of a part throttle 1-2 upshift, and i basically ended up, for lack of better words, flooring it in between gears.

i recently found out that my ZZP kit wasnt installed fully, because their instructions were.... off, to say the least. this might be why i didnt notice any difference in upshift quickness. this also might have hurt my input shaft here because it allowed my tranny to slip more before locking into 2nd when i hit this "odd" shift

the only problem i am having right now, is money. lol. this trans has 7k miles on it and i already went broke putting this in. my old trans just... died of old age (172k miles on it)

so im trying to find out what is the cheapest i can do this for. i have somebody who can sell me some GXP chains for $40 + shipping (are these good?) and i can get a ZZP 4340 input shaft new in box for $325 shipped.. so this MIGHT be feasable... but i still am broke. so ill have to pay this off, and its not going to be fun considering i am in school full time.


if i did these 2 parts, would my trans be sufficient to my level of power without having to worry about breaking it too easily?

thanks. if i had $$$ i would do the 7/8ths chain and the pump shaft, but i am just honestly trying to fix what i got right now, i need transportation....

thanks!
 
yeah... lol

well, i been thinking about how much of a ****ty time i put my poor mother through when my car is out of commission.. and i might just have to suck it up and buy:

4340 input shaft (i can get for $325 shipped)
and GXP drive chains (i can get for $40+ shipping)

this is going to make money really tight for me for now, but i can probably pull this off, and nothing more... lol

so trannyman (or anybody else chime in) will this setup make my car more reliable for my DD with my mods? if i can make my tranny pretty reliable for my current setup, ill do it

cant really afford an intense shaft right now, or a 7/8ths

but if i can do a 4340 shaft and GXP chains and not have to worry about replacing broken **** so much, ill do this.

of course i understand things can always break... just bad luck, but im just looking to make my tranny reliable for my DD on the mods i have without bieng on "borrowed time" so much

thanks!
 


As long as the rest of the trans is still good such as clutches you should be plenty safe with the better input shaft and the GXP chain set as those are stronger than the original V6 chains, just make sure if used they arent worn and badly stretched. Definately go back over the shift kit stuff or as mentioned above get the Intense kit and call it a day because it is a world more complete and nicer setup than what you have now. Single chain conversions really arent a big deal at your level especially since you will be going with the GXP chain set which is a bit stronger and there are plenty of guys well into the mid 12s with those chains that are holding up just fine.
 
thank you so much for your help

the GXP chains are really low miles

and my clutches SHOULD be fine... i would hope, considering this trans only has 7k original miles on it. lol

so now im excited... motor is almost out

thanks!
 
ok, motor and trans are out, the input shaft broke PERFECTLY clean along the o ring groove

now the input shaft i got off my forum member does not have the o rings on it, where can i get rings for this shaft?

can i use stock ones from a stock input shaft?

and while im replacing the shaft and chains, is there anything else i will need to replace while im in there? side cover gasket should be fine i hear?


and what about torque specs?


thanks!
 
The seals on the input shaft are teflon and require special installation and resizing tools to properly install and resize the seals so you can put the shaft in the trans without damaging the seals. You can try to get around this but it can be tricky to do. The oring groove section just uses a regular rubber type oring. I have plenty of the seals either or for the input shafts if you need them or I could install them for you, or you could even try a local trans shop and cross your fingers they dont hit you hard cost wise. You will need new channel plate and valve body gaskets to replace the input shaft and the rest you should be save, just take a peak at things the best you can and check the condition before going back together. Torque specs are on the Info page of my website.
 
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