727 noise in reverse

[crash340]

Trans guru's, when I reverse out of anywhere, the trans makes a noise not unlike when you apply the brakes after the car was wet and the discs have a slight rust film on them, kinda growling/wooshing noise, it has a Tansgo 2 kit in it, outside that its fine, shifts through gears ok etc, any clues?

[dodj]

Back drums maybe?

[crash340]

No, checked that by application, the noise is separate and coming from the trans

[don340-4]

  crash340; I have the same noise coming from my 727 in reverse, kind of like a whistling or as you described a whooshing/growling, mine only makes the noise when it is cold. I have posted my problem on the site before, nobody seems to have ever heard of it. I don't think mine has a Transgo kit. Lets hope someone comes up with a solution, it is really annoying & if anyone is around the car when I back out of the garage they hear it also. I am using F type fluid, how about you?

             

[crash340]

Thanks Don,
yep F type fluid as recommended, I had the pan off it recently to try and determine its condition and fit the kit, there was no crap in the filter or oil so I dont suspect any great issue with the trans however I cant confirm its condition further. I will be rebuilding either it or another in the next twelve months, maybe its just some bush/bearing/gears a little tired. But yes its kinda loudish.
Greg

[6packCuda]

Can't think of anything in the trans that would make a noise like that in reverse only. Could it be a u-joint?

[burdar]

Check that the exhaust is tight and not close to hitting anything.  When I first got my car together, the exhaust made a noise like that only in reverse.  I had to space the tips down away from the valance a little more.

[crash340]

Pipes are good, Uni joints are new, definetly coming out of the trans, a light scrapeing noise

[don340-4]

 crash340, Were you ever able to discover what is causing the trans noise in reverse?  Mine still makes the noise.

   

[crash340]

Hi Don
No sorry, I have not, I have taken to now starting the car in N. That may have helped it a little, but not sure, to be honest I had kinda forgotten about it. I'll pay attention when I back it out this weekend and let you know

[mopar jack]

My car does this every time I take it out of the garage if I don't run it in neutral for a minute. It's usually caused by converter drain back.

[crash340]

MJ, does your car also pull forward a very small amount in N if it hasnt been started for say a week, mine does, just a little

[don340-4]

  I guess we just live with the noise, I will try the neutral start procedure today, Let you know. There has to be an answer to this problem, I have had quite a few 727's, none of them ever made this noise  only in reverse when cold.


     

[crash340]

I just backed the car out again, the noise has pretty much gone, but I do start it in N, I'll start it in P and back it out to see if the noise is there

[1 Wild R/T]

Two possibilities as already discussed convertor drain back and the other is a fluttering relief valve.... When you put the trans in reverse fluid pressure is boosted to maximum allowed by the line pressure... Line pressure is basically controlled an adjustable relief valve, in forward gears the pressure controlling clutch & band application is a combination of line pressure, governor pressure & throttle pressure.... In reverse throttle pressure & governor pressure are removed from the circuit so full line pressure boosted to max is used to apply the band & clutch... Reverse is the only gear where pressure is boosted to the point of lifting a relief... If the relief valve flutters it will cause a groaning or squealing noise....   

Nothing to worry about...