vibration in 3rd only
Thread Starter
On The Tree
Joined: Oct 2002
Posts: 133
Likes: 0
From: illinois
vibration in 3rd only car shakes in 3rd gear at any speed and when it shifts to overdrive its gone instantly. i ran my pinion angle wrong for a few thousand miles. tranny is flp lvl 4 installed apr 5th. i replaced ujoints, did nothing, corrected pinion angle (+2 at ds +3 at rear) and it made a huge diff overall but 3rd gear still vibrates no matter what speed. my only guess is maybe the output shaft bushing was damaged with the incorrect pin angle. car was smooth as butter when i first put in all the drivetrain parts. few thousand miles later i have this prob. anyone know if this could be related to the trans/converter or that output bushing? drivetrain mods in sig
Launching!
Joined: Jun 2004
Posts: 269
Likes: 0
From: Mooresville, NC
Problems like this are very hard to isolate and pulling the transmission to troubleshoot it can be a crapshoot, but since it happens in THIRD only then it really narrows it down to the transmission. Third gear in a 4L60E is Direct Drive so all the internals rotate at the same speed. If something is out of balance in the transmission, third gear is when it will surface.
I doubt its Torque converter related, but you can always try to re-index it to the flywheel and see if it helps.
I doubt its Torque converter related, but you can always try to re-index it to the flywheel and see if it helps.
I had experienced a 3rd only vibration in my 4l60 for about a year now. I went through 4 rebuilds of 3-4 clutches last summer...and just this past weekend.....3-4 went again. Dont' know if that is what you are experiencing.....but mine only vibrated in 3rd as well.....as soon as 4th kicked in......it went away. Might be your 3-4 clutches giving out.....sure is what my recurring problem is...........
Thread Starter
On The Tree
Joined: Oct 2002
Posts: 133
Likes: 0
From: illinois
well i wrote chuck at flp last night. hope to here from him in the next couple days. i havent noticed it slipping but shifts arent as firm as they were when i first had it installed. i never go wot into overdrive, i always let off before it shifts. i find it hard to believe that with only a lid and a catback that ive killed the 3-4 clutches.
i have the largest cooler you can get and a deep trans pan. i checked the fluid and it is nice and pink, like new. i cant wait to have the funds for a 4l80e conversion and be done with the 4l60e, but i would like to get more than 5k miles out of this 2k$ trans. i also have a lot of play in the outputshaft and whatever it runs off of.
i have the largest cooler you can get and a deep trans pan. i checked the fluid and it is nice and pink, like new. i cant wait to have the funds for a 4l80e conversion and be done with the 4l60e, but i would like to get more than 5k miles out of this 2k$ trans. i also have a lot of play in the outputshaft and whatever it runs off of.
STF Veteran
Joined: Oct 2003
Posts: 3,486
Likes: 0
From: Greensboro, North Carolina
Must be a chevy transmission thing. I have the stock 4l60 and my third gear vibrates also. I have asked people about it before and no one had an exceptable answer. Third vibrates until the instant it hits forth and then it stops.
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Telling yall.......3-4 clutch pack...your feeling the clutches slipping........eventually they will go. Of course, i could be wrong.......i've been through 4 clutch packs for 3-4 and it does this everytime. These are the weakest clutches of the tranny and the most common failure.
My fluid looked clean also....till i dropped the pan at no more thna 1000 miles of use since last rebuild......sludge built up on the magnet in the pan at least 3/8 thick. My 3-4 jsut went again this last saturday. Turbo 400......here i come.
I don't know what GM was thinking with this car really. They take a high HP/Torque car and put in a S-10 tranny and rear end behind it. Not exactly one of GM's shining moments!
My fluid looked clean also....till i dropped the pan at no more thna 1000 miles of use since last rebuild......sludge built up on the magnet in the pan at least 3/8 thick. My 3-4 jsut went again this last saturday. Turbo 400......here i come.
I don't know what GM was thinking with this car really. They take a high HP/Torque car and put in a S-10 tranny and rear end behind it. Not exactly one of GM's shining moments!
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Im bumping this as I started having this issue last summer, and I have the trans out as im dropping a HCI lq9 in.
Did anyone ever figure this out, I dont want to go to the effort to put it all back together and have something break now that ill be making a little more power.
Did anyone ever figure this out, I dont want to go to the effort to put it all back together and have something break now that ill be making a little more power.
TECH Resident
Joined: May 2006
Posts: 969
Likes: 119
Since the transmission was rebuilt and most likely the builder installed the Beast sunshell. The Beast sunshell is not balanced and sometimes one is more out of balance than another. It will always show up in 3rd gear, and go away in 4th gear. The late GM hardened sunshell is balanced, and you might consider it if you want this fixed. I have one in a mid nine second 1996 Firebird with over 2,500 passes, and many others in ten & eleven second vehicles with no failures. I offer the Beast to those who want it but with the "out of balance" notice.
Actually Dana the factory shells are not spun balanced. They are balanced to a degree but this all done while they are sitting still. I have very close ties with the manufacture of the beast made by Parker with my new job. In the future they are working on a new designed shell that will have a bearing, machined race, hardened areas and spun balanced. This will be a performance version for the guys that want the best that can be offered! Vince
I do not have an answer on when it will be ready. At this point they are working on it and looking to test the interest on this design in the market place. I think it will be a very popular design and from what I have been told the current design will still be offered as well. To be honest I do not know if the new design would be made any thinner but hardening the sides of it are definitely on the table at this point. I believe you received a call about last week from a friend of mine about what happens to shells on forced downshifts with a sprag that slips. After seeing the pictures of that shell bending I think it might be a good idea to keep it the way it is and also harden it in this area. Vince
same here... DAMN IT. I just picked the car up from the tranny shop today. Full rebuild, Beast sunshell, z-pac, and aftermarket servos, and it's STILL got that vibration/hum in third. Any more thoughts? Think it's safe to drive?
