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2nd gear downshift near 100MPH. HELP!!!
This is a discussion on 2nd gear downshift near 100MPH. HELP!!! within the General Help forums, part of the LSx Technical Help Section category; ...
10-12-2006, 07:48 PM #1
2nd gear downshift near 100MPH. HELP!!!
Hey guys, I really need your help here. Ok, I was driving down a wide open street and I was ahead of all the traffic, so I decided to down shift and hit it. I was in 5th doing about 60mph, and I downshifted to fourth, realizing I still wasn’t in the power band, I shifted to 3rd. I got into 3rd fine, and climbed up the RPM scale until I was at about 5600-5700 RPM’s when I went to shift hard into 4th. However, for some reason (and I still do not know how) I shifted into 2nd. The whole rear-end locked up, as quickly as I could, I shifted into neutral. The check gauges light came on (not SES light, though), and I shut the car off at the next stop light (almost immediately after). When I went to start it up, it hesitated for a second and then started up. To my extreme surprise everything seemed to be alright. The reared wasn’t blown, and the car was actually driving. As soon as I could, I pulled over and popped the hood just to check everything, and I heard a distinctive tapping noise coming from the block. I pushed the throttle body chain and the tapping sped up, relative to that. What the hell did I do? What is this noise? How should I go about fixing this? Also, 2nd gear felt longer/looser than it ever did, after this incident. Will I need substantial transmission work or what? Please let me know anything you can about any part of this, it would be a huge help. Thanks a lot guys.
10-12-2006, 07:54 PM #2
well, hopefully your rev-limiter stopped you from floating your valves, but if it didnt, your pistons could of hit your valves and f'd up something to that nature. maybe-someone correct me if i'm wrong- but you could have jumped timing.
10-12-2006, 08:21 PM #3
Well did the some thing...TWICE!!!!. once when i first got the car(the same day) and the second at the track. scared the crap out of me.. then that horrible ticking... i thought it was all over for me the first time that i heard it.
But all is not lost. it is most likely a push rod - EASY FIX
For this process you will need to get a couple tools:
1. a engine stethoscope - any pep boys, auto zone, O Riley's.. etc etc
2. 6 pack of your favorite beer - any liquor store and some grocery stores.
find on which side the ticking is coming from with the stethoscope. You really need to use it too. I thought my ticking was coming from the passenger side but the scope said driver... and what do you know it was. the scope even told me which cylinder it was on.
1. Remove your tower brace- if equipped
2. remove the coil pack form the affected side
3. relieve the fuel pressure at the shrader valve located at the end of the fuel rail. be sure to place rags around to catch the lost fuel...but it won't be much. i had maybe 1/8 of am ounce come out of mine.
4. remove the fuel lines with the proper tool required.(I didn't have the tool nor know what tool to get. i worked with them still secured)
5. remove the valve cover
Now from there i removed the each of the rockers one by one. once one rocker was removed i pulled the push rod out.
as soon as i pulled it out i marked the top end with a magic marker so that i could put it back in the way that it came out.
check each rod for bends by rolling it on a piece of plate glass(i used a old fish tank on its side)
The stock rod will all have a slight skip to the when rolling them as there are small burrs at the end from when the pressed the ends into the rods.
You will pretty much know when you pull it out that it is bent by looking at it.
if you find one that is bent go down to the dealer and get a new one for 17.88 or order one from pep boys and wait the one day it takes to come in for 5.23. you call on that.
when installing a new push rod be sure to put assembly lube on the ends. be generous with it too. the lube is cheap. i put lube on all my push rods when i put them back in but I had nothing else better to do with the tube i have.
once you have all that back together just torque down your rocker arms to the specific torque....off the top of my head i think it is 22ft lbs... but not sure. make sure that you are not on the valve "open" part of the came lob for the particular cylinder's rockers.
For myself i tightened them all down to specified torque then turned the engine over till i got where one of the sets were fully closed then i re torqued. then turned engine over a bit more till the next one was fully closed and repeated till i was done. put the valve covers on and torque to 122in/lbs(11ft/lbs will do) and coil packs back on and you should be good to go.
Hope this help. i got a new valve cover gasket but have been told that you can reuse the stock one.. your call on that. if you have any questions you can PM or reply thread.
I just did this fix 2 weeks ago so it's still kinda fresh in my head.
10-12-2006, 08:29 PM #4
Wow. Thanks a lot. I really didn't expect such a thourough anwser from anyone. So, you did it as well, and everything's ok? Except for the pushrod of course. Thats really good news to me, because i was expecting a whole list of things to be screwed up. How are your gears/ trans. after your similar experience, worse or no difference?
10-12-2006, 08:46 PM #5
my bet is bent pushrod(s)
10-13-2006, 05:16 AM #6
- Join Date
- Mar 2006
- St. Louis
- 02 z28
most likely bent pushrod, pretty easy to check and change, pull off the coil packs, then the valve cover, loosen the rocker arms and rotate them out of the way, pull up the push rod then check to see if it is bent in any way. if not put it back in (i like to put a little oil on them when i put them in) line up the rocker arm and then tighten it down to the specific torque specs(i can't remember but i think it's like 21-22 ftlbs), keep going till you find the bent one, i'm betting it's a bent one, as soon as you change it the tapping should go away.
edit, i just fully read plash riots post...his is more detailed but you get the point.
if you need some push rods i have some laying around i could ship out.Tony
02 Camaro Z28
UltimateSR <-- Join it!
10-13-2006, 08:20 AM #7
As far as my gears. I so no differance. shift just like it did before. luckily tires broke loose instead of something else breaking. had freind that did the same thing in his mustang and obliterated his tranny.
10-13-2006, 09:04 AM #8
- Join Date
- Jan 2006
- Shepherd, Michigan
blacker than wesleysnipes
- 98' trans am
i'm about 99% sure its a bent pusrod..but man you are sooo lucky you didnt float the valves and screw alot more up..and your tranny..but yea good luck man ! tell us how it goes/ what was wrong.
10-13-2006, 09:13 AM #9
one time I redlined 2nd and went to first too! Scared the shit out of me too. I've got no ticking though. I haven't shifted on a hard turn since hahaha!
10-13-2006, 10:23 AM #10
Glad I bought a auto...i'm sure there's people out there that would just pawn their car off to some poor soul after a miss shift like that....basturds
10-17-2006, 05:21 PM #11
Ok, it ended up being bent pushrods like you guys all said. 7 of them were bent, and 1 was tremendously bent. I mean, 1 of them had like 30-40 degree bend on it. The compression test came out good on the heads, so thats all good. All the pushrods have been replaced w/ chromoly ones so everything should be good. I barely drove the car at all after this happened (less than 25 miles) but is there anything else w/ the engine that could have been screwed up, besides the heads(cuz it was fine)? Thanks for all ur help guys.
10-17-2006, 05:27 PM #12
it depends on how high it revved when you shifted. If you lefted it in 2nd long enough for the motor to rev all the way up, then there could be more damage. No matter what your rev limiter is set at, if you lefted it in gear long enough for the motor exceed the factory rev limiter, it will pass the rev limiter and continue to climb because of the clutch being locked to both the flywheel and the transmission which is also locked to the rear end. So the rev limiter is only good if you are accelerating the motor through air and fuel combustion, it does no good if your rear tyres are turning the motor.
But if it doesn't make any noise now then you are probably good to go.
10-17-2006, 05:37 PM #13
How it run after replacing the pushrods?? Any unusual noises??
10-17-2006, 05:45 PM #14
There is little change that the engine jumped timing, the LS1 has a double timing chain, not a stupid belt like a Honda. For that chain to jump it would either have to be very lose or just break completely, in which case the engine wouldn't run. Not something I would even consider worrying about
10-17-2006, 05:50 PM #15
But, thats what im saying, if significant damage was done, redlining, then the cylinder would have hit the the valve and there would significant leakage. Right? Then the problem would only be the head, and nothing else?
10-17-2006, 05:53 PM #16
Yeah, it seems to run fine now. I guess im just trying to make sure that there are no problems or potential problems i do not realize. But just by driving the car, it seems perfectly fine w/ the new pushrods.
10-17-2006, 06:01 PM #17
If that were the case (unlikely by what you described), you probably need a new head as well as new pistons, since they would be damaged from the impact with the valves.
10-17-2006, 06:08 PM #18
Oh ok, thanks. But i doubt that is a problem, because like u said that would be very noticable. and right now there is nothing noticably wrong w/ the car, so hopefully i got lucky, and need to move up to pro 5.0 to ensure this never never happens again.
10-17-2006, 06:15 PM #19
I love my Pro 5.0, best shifter I've ever used. Took it to the track, shifted as fast as possible, and didn't miss one gear either run.
Its got the most direct feel of any shifter, absolutely no rubberyness at all. Hard to miss gears when they are exactly where they should be and easy to find
10-17-2006, 06:39 PM #20
"response to the first post"
that must have scared the living SHIT out of you!!
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