Hey guys how are ya? Been a while since I last posted in here. The my car has gone through some changes now. Its a 2000 z28, was an LS1 car till I spun a bearing and decided to with an LQ4 off a low mile 06 GMC 2500HD. Recently my Trans gave out on the last burn out I did on a summer day so I had it rebuilt with a shift kit. The reason im making this post is because my transmission has a vibrating issue more like a shutter. Its minor when it shifts from 1st to 2nd, then you feel it a little more going into 3rd, its smooth going into 4th until I reach a certain speed where its a bit constant. I went online to try and search what kind of issue this could and found one post that it could have been torque converter that was not balanced. So I took it back to my rebuilt guy. He had the car for a week, took a everything apart, replaced the TC along with some other parts. I must say it shifts better BUT that vibration is still there. At this point I know well its not my transmission. I had other doubts like maybe my wheels needed balancing so I did that. My other doubt was maybe I had warped rotors so I replaced those with Brake Motive rotors. I thought maybe replacing motor/trans/torque arm mounts with poly would help, nothing. Where else should I be looking? Replacing driveshaft? U Joints? Pinion Yoke? Any pointers or suggestions are greatly appreciated. Thank you.

 

Hey man. I kept the 4L60E. Did a full rebuilt with a shift kit. Its just a stock 6.0 nothing too crazy, just exhaust really. It vibrates when it shifts, minor at 1st going into 2nd and you feel it a little more going into 3rd. Its smooth on 4th and when Im driving at fwy speed around 75-80 at 2200rpms its constantly.

 

Is it a vibration or a clutch shutter

 

Its shutter as it shifts. I feel it more when I left off the gas.

 

To be honest, Im not sure but If I remember right he did a full rebuilt. He didnt re-use any old parts.
He took apart the transmission twice and swapped out again the same parts with new cause I have a one year warranty. The second time I got it back it responded better, and shifted better but that constant shutter when shifting, and at cruising speed of 75-80 is annoying. I wish I could record a video but it would be hard to tell. He noticed the pinion yoke having a bit of a play but when it comes to that I have no clue what kind of parts to buy and replace.

 

Do I need to buy some sort of full rebuilt kit for that or just the bearings itself?
Im sorry I dont have any sort of knowledge when it comes to things like these.

 

I would greatly appreciate it if you could possibly link me up to what I need.

 

Slipping clutches or a band will make a shutter but not when lifting off the gas. What happens when you manually shift it on the late side? How is the tranny mount?

 

I may just have one of my good mechanics take a look at it. If it requires changing ring and pinion, I might as well invest in some bigger gears or just have the entire thing built. Thats another good option, Looking for a rear end like you said.

 

but how is that possible when its been taken apart twice and swapped for new internals? I havent manual shift on my automatic. Tranny mount is new. Poly both trans, motor and torque arm.

 

Get your rear differential fixed. Replace the poly trans mount with a OEM mount. I personally dislike polyurethane engine & trans mounts on street cars in just about any application.....Using them on Torque arm cars for the trans mount is the worst.

 

I wound change the poly trans mount first with a stock mount from GM before doing anything with the differential. Did he say what type of play is in the pinion yoke (up and down or twisting back lash play)?

 

I was in the transmission business for a long time. Anything is possible and there are lots of guys out there that are hacks or parts re placers. The reason for manual shifting it late is to see if it has a pressure problem at light or normal shift times. Best bet is to put a pressure gauge on the trans and make sure it has the proper pressure. Was there a shift kit/improver kit put into it and what one? Updated servo? Its very hard to determine vibrations in person never mind over the internet but you said you have it on the highway at 75-80?

 

The tranny mount might be the problem. The new 'OEM' wasn't even close in height to the stock one on my Z28. Just a 1/2 inch difference in the height of the tailshaft of the transmission is enough to cause the front ujoint to vibrate. Why because the front end of the driveshaft is actually lower than the back end of the driveshaft. A pinion angle gauge will help to determine the difference between the front and rear of the driveshaft. You might have to shim the tranny mount to raise the tailshaft ever so slightly.

Install the old transmission rubber mount and take it for a drive. It doesn't take long to do that. Compare the the stock and new one for height difference.

Or put it on a drive on lift - some good ones have jacks to raise the car off of the ramps with the car still loaded on the drivetrain. You can see the front u joint vibrate if that is actually what is causing the vibration.

IMO an aftermarket K-member can make a difference too - a 1/2 " difference can and will raise or lower the tail-shaft of the transmission - at least it did on my car.

Pinion angle can cause vibration too. On my Z28, anything more than -2 degrees and it will vibrate as I unload or unload the drive train (shifts gears).

If your pinion bearings are bad or going out - they will shudder terribly if you drive in very short figure eights in a parking lot.

Do you have an auburn or torsen posi?

 

So I did what you said last night, manual shifting. The vibration definitely feels like its coming from the rear when I let off the gas. I believe the shift kit he used was a transgo. after a rebuilt he pressure tests them. He has a dyno to do so. It really is hard to describe it. Really wish I had local buddies to have it checked out.

 

Thanks for your reply. All I know its the stock rear end. I havent done a thing to it since I bought it back in 2007 except for getting the axles replaced a few years later. Its definitely a shudder alright when shifting. for instance today going 50mph on 3rd gear its a bad vibration. All mounts are new, Motor, Trans and torque arm mount and I must say it feels better than the OEM ones. It feels firm.

 

IMO if you checked the driveshaft to assure it is at least level or higher in the front than the rear of the driveshaft - then next step is to set the pinion angle back to zero for now while you test to see if it stops. You can adjust it to minus zero later after testing - to rule out wrong pinion angle.

If it still continues to vibrate, then perhaps the pinion bearings are bad. When mine went bad after a GM installation of the pinion seal - the vibration was terrible. GM did warranty it, however.

After a test drive, listen if you can hear the rear end popping and snapping. It will be extremely hot to the touch if the bearings are bad. The noise is the oil boiling.

https://ls1tech.com/forums/gears-axl...vibration.html

An auburn posi has clutches and requires an additive periodically. The torsen posi does not have clutches and requires no additive. The clutches typically bind when navigating left or right turns if an additive is required for an auburn.

 

I caught that dont worry but what was the initial thread post? After he had his transmission done he noticed a vibration. Who installed the trans and missed a loose rear?

Now to the op...Transgo is a great shiftkit and him dyno-ing it is also a great thing. As I said vibrations can be so much fun!!

 

Yea, go fine tune and adjust the pinion angle and change the mounts, **** the loose pinion bearings.[/QUOTE]

I've owned my 1998 Z28 Camaro since early 1999(8K) miles (almost 19 years) and while it was still under warranty .

Posts about loose pinion bearings and a clunking rear end were in the hundreds back then when these cars had less than 36k. Ask me how I know? Because GM techs admit the 10 bolt should never have been installed in these cars because the rear ends where built so cheaply.

So the typical response to the customer when you took the car in was that they all sound that way and send you out the door up until the car would go out of warranty. After warranty, GM was more than happy to replace them.

Same for the aluminum driveshaft that had internal welding cracks and it would tick and ping when you put the car in gear. Same reply, they all sound that way. BTW - they finally did replace the driveshaft under warranty because the weld was visible externally. And of course - elcheapo front rotors that would warp too -same GM reply

As for my second reply in this thread, I thought the OP should rule out the easy stuff first then move on to the rearend. My statement "If it still continues to vibrate, then perhaps the pinion bearings are bad." is actually in agreement with you. Sorry that you didn't read it that way.

The OP's mechanic said the bearings were 'loose'. If he did suggest to the OP that they should be replaced - the OP doesn't say. Should the mechanic instead have told the OP that the bearings were 'bad' and should be replaced? IMO - if that was his diagnosis - that's exactly what the mechanic should have suggested. "Loose' IMO isn't best word to use if something is worn out and needs to be replaced.

For you, 'loose' means the same as 'bad and should be replaced'.

To me 'loose' means there is some play. Back in the day just loose wouldn't get them replaced.

On a side note; it is suprising that no one has asked the OP how many miles are on the car.

 

Vibrations are annoying but I will take everything in this post into consideration and have one of my dads good ol mechanic take a good look at it and hope for the best.