Torqueflite 727 "clunk"

[woodwiz]

Coming out of park to reverse and or passing back thru to drive and i get that damn "Clunk".
Should i be overly worried or does she need adjusting??

 

[69hemibeep]

Might be the driveshaft, there is a little play in the rear end and you might be hearing it from there. Is the idle on the high side? That can make it sound worse. Could be normal, or wear in the rear end or U-joints or the transmission which I doubt.

 

[Plybeep68]

I agree with Hemibeep, check the driveshaft 1st

 

[woodwiz]

I shall....Thanks!!

 

[woodwiz]

I checked out the driveshaft and it is solid.Looks like it has new u-joints at both ends,perhaps like you said it may be coming from the rear end...the search continues!

 

[Russ69Runner]

What rear end do you have. Is it a posi or limited slip.

 

[woodwiz]

Can I find that out by numbers on the fender tag or markings on the differential ? My guess is limited slip.

 

[Russ69Runner]

You will find marking's on the chunk like this. X for 741- 2 on the 742 Then their is the 489 Three types. I rebuilt my 741 new ring gear and pinion. But still some slack in it. The spider gears are worn also. But going to run it till I can put the other chunk in it I got. Even the spider gears can give you a clunk sound. Going forward then backing up could give you a sound.

 

[69hemibeep]

It might be nothing but it doesn't hurt to look it over. We had an old Plymouth growing up that the drive shaft would almost ring putting it into reverse. Never any trouble with it.

 

[woodwiz]

Took it for a spin to get fuel and it did it at different levels of noise. Could some energy be coming from the torque converter ? But it does sound like it's coming from the rear end.

 

[Russ69Runner]

If you can get some one to sit in the back seat when your driving they should be able to here it better than the driver. ?

 

[woodwiz]

Here’s a pic of the rear end w/numbers.

 

[woodwiz]

How does anyone read these rear ended numbers?

 

[Russ69Runner]

Have you tired to Google those numbers. Several Mopar sight's to look into that. That 9 is throwing me off. May be the rear end has been changed out. Sorry not much help I guess.

 

[woodwiz]

Yes sir, i believe a lot of parts have been changed out on this RR. But I will probably always be guessing on that unless I dissect the vin and fender tag with engine,tranny and rear end numbers. It doesn’t matter to me very much, just want it all to work like it should.

 

[Russ69Runner]

If you have a local Mopar club or a group of guy's that have a car club would get with them. Those guy's work on their cars a lot and are help full also. That is part of the hobby with car guy's. If you can take the drive shaft off at the input to the rear end then grab the pinion and turn it with your hand. Turn one way then the other and see if you feel that clunk sound. Should be some play in limited slip but that is what I did after getting my chunk back in the car. Knew that the spider's where my problem. The pinon and ring gear are new in mine and set up. So this will tell you more or will have to take it out and check the ring gear and pinion.

 

[droptop]

Some noise is common when changing from forward to reverse. What is your idle rpm?

 

[woodwiz]

About 900rpm.

 

[droptop]

Take it down to 650. That is the factory setting.

 

[woodwiz]

Yes sir the idle is down within specs. But of course when it’s cold on a first trip of the day is when it’s more pronounced. Has anyone figured out my rear end numbers...my guess is limited slip. Some research would indicate with that 489 number that it is heavy duty...which is nice!
The search continues!