Usually once the car is warm, it really clunks, and I mean BAM when I move it from Reverse to Drive or the opposite. I also experience a similar sound/feeling when the car is in 3rd gear and decelerating towards a stop. It clunks real bad as it downshifts automatically. Will not do this if its in 2nd, or in OD. What gives? Brand new trans, my car did this with the old tranny as wel though. New poly mounts all around. Motor mounts, trans mount, torque arm mount, the works. Like I said, I figured when the tranny went out and I swapped it with a pro-built, that this would go away. But it still persists and it is damn annoying. Any ideas? Also had the ds balanced and new u-joints were installed.

Will

 

Did you ever get this figured out? Check to see if you pulled the stud out of the poly tranny mount and see if the cross member that holds the tranny is tight if not.

 

The wore out 700 I just replaced did that. The U joints were fine. Slipped lots when cold and a bit less when warm. It's perfect now with the newer one.

Some of the resedent tranny guys will know exactly what that is. I haven't rebuilt a 700 myself but when I get a bit of time I'm gonna give it a shot.

 

not really much help to me fellas. but thanks

 

Er, mine does the exact same thing. What about N-D or N-R? Same thing? What's your idle in N and D?

 

yeah same ****, idle does not change but maybe a 100 rpm if even that from n to gear, so its not like its going from 1500 down to 700 or something... what gives. this is really starting to **** me off

 

Sorry, what I wanted to know was what it's idling at when in gear and when in park. Like the rpm, not the difference in rpm.

My idle was pretty high, like 800, so it clunked real bad. Turned it down, and it got a lot better.

 

My idle is fine. It's almost as if there is a **** load of play between the trans and rearend somewhere. like when its engaged it moves or something. ****ing weird, I wish someone could point me in the right direction.

Will

 

mine does to but i dont have any idea. if nothing else i just posted so u know it happens to pther people too

 

Well after asking around the consensus seems to be that it is play in the diff. The rear end must be worn and the play is causing this flexing action. I might just throw in my old rearend as it is super tight and has no play. Figures!!!

Will

 

Im having the same problem. When on jack stands and having a friend shift it for me while im under the car, it sounds like its defiantly coming from the rear end.

What could it be and how can i fix it without having to change or replace the gear?

 

Ive beena really thinking it was the tranny but since i read this post its sounds just like you alls problem. Im just hoping it isnt the tranny?

Can pulling the diff. cover tell me if its the rear end or not for sure?

 

I thought it was the trans too, then the stocker blew out so I threw in a pro-built unit. Still did it. Replaced EVERY mount/bushing on the car with poly ones, still did it.

You should be able to tell by unbolting the driveshaft. If you grab the yoke where it meets the rearend and spin it by hand, you will most likely hear your noise. My original 2.77 rear makes no noise, so I am going to go through it anyway and beef it up a little. Hope that helps

Will

 

I had the same issue with mine, was the rear end too. I went thru with new bearings, and reset the backlash. Lotsa work for a clunk, but it needed new stuff inside anyway.

 

Mine does the same thing. Makes a clunk when shifting from r-d or d-r. It also makes the noise when the trans automatically downshift into 2nd when coming to a stop. I've suspected the rear-end might be the problem. Sounds like it is. My car only has 20,000 miles on it so maybe it's not that big of a deal. I don't think mine is as loud as yours though.

 

if it makes the clunk it sounds like u guys agree the rear end is loose, so if it is will that make it wear faster or have problems?

 

So did anyone ever find out a good fix for this problem, my car also does the same thing, its 85 and has lots of miles on it. I was just going to post this problem,but I searched first,good for me right? lol...

 

I guess the diff seems to be the unanimous culprit. Although I am not sold on that 100% just yet.

Will

 

Mine does the same too (as far as the OD or 3rd downshift) So i just put it in OD as i'm slowing down.

I think its because my 10 bolt is about to die

 

When you rebuild your rear ends, make sure you don't use a crush sleeve, use a solid spacer. Takes more time to set up but much stronger and your backlash will not change. Also you need to install a heavy duty back cover with the bolts that tighten up against the caps in the diff.

 

Why install the heavy duty back cover?

 

Thanks man ill remember that. I am rebuilding the rearend very soon so i'll keep that in mind

 

I have a problem too. when i start my car in 1 from park it hits realy hard. but if i go from park to D or OD it feels just fine.

 

WHen i go from park to drive, i get a tire chirp and a clunk. im pretty sure the tranny has a shift kit from past owner, but if my diff is loose, would it chirp the tires when shifted to drive? im assuming the rear calipers are seized. im ordering that GM REAR caliper REBUILD package..GM #18019028 hopefully thats helps the wheel from chirping. I changed out the tranny bushing, torque arm bushing, and rear sway bar bushing all with poly. i get a less clunk with the sway bushings, and tire chirp when shifting to 2nd while under hard accel. For a 305 TPI, 700r4, you recommend staying with 3.27 or doing 3.73. Im going to rebuild the rear end eventually and just planning ahead. thanks

 

BUT; there is NOTHING sexier than a third-gen. Aint they cool?

 

i have the same problem, except, my torque arm is turn to ****, the tranny is brand new, as is its mount. and my rear calipers are seized. so i get no buck when i start it up first thing in the morning, but once the car warms up it hits pretty hard. but once i lower the idle and put new calipers in the back ill see if it changes

 

Im having this issue,and its getting worse...it use to be just a clunk upon a 1-2 up and 2-1 down,now its thats and a clunk engaging from n-d and espesially from d-r,i have alot of play in my trans and rear end none in the u joints,and at tme its feels like the drive train is of balence in some way causing a vibration..the tranny is less then a year old,I have a T/A cover on a 9 bolt 3.27 with 80k,all tubular pan hard suspention. please help thx! maybe its time for a 3.70 gear?

 

I have the same problem... I just rebuilt my tranny in hopes that it will fix the problem.. i have not tried out the car yet with the new tranny in yet but i will be sure to test it out... I suspected it was the tranny... if it's the rear end then i'll be pissed!

 

Yea,come to think of it,this other noise happins only AFTER I go in reverse while turning a bit(not during)then when moving forward at idle speed, it feels like a binding noise followed or combined with a pop,like "cunkcunk,pop".
so then you goose it to see if you can make it clunk,and nothing,its fine or sometimes feels out of balance, a slight vibration,and then of course the clunk on the 2-1 down shift.

Also has a vibration on take off sometimes,and I swear it throws my knock sensor off,and my car retards.it really pisses me off,i wana fix this.
sometimes itll give a perfect take off,with a nice firm shift and no clunk,but later in the day itll come back..
Only time it feels great and smooth,is usually above 60.