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Bren67Cuda904
 Post subject: Strange 1-2 shift.
PostPosted: Tue Nov 13, 2007 4:56 pm 
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Joined: Tue Jun 27, 2006 8:21 am
Posts: 1614
Location: Orlando, FL
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As many may know I am running a very recently rebuilt and modified 904 with the 999 conversion.
Quote:
Not much to look at here, but it a picture, and I love pictures of anything.
http://tinyurl.com/23k786

The front pump and shaft where change out to the more common larger type which will now match the new 3200 stall convertor I got from Midwest. (ps I am running a 74 crank) The plantaries and directly related gears/drum where installed from a 999 which give me a lower 1st and 2nd gear. I am still a little unsure of the ratio, but the stock ratio was 2.45/1.45/1:1 and the new one is at least 2.75/1.54/1:1 or there abouts. If some one could clear this up for me that would be great. Also because of the drum change we were able to install two more frictions and steels for a total of 5 and the band is wider. The lever that was in there was a 3.2 and it was replaced with a 3.8. The shop had a deep pan lying around and just went ahead and installed it also.
Out the door not including torque converter was $850. It sure seems like a very good price to me.
If I am accelerating with at least 1/4 throttle, everything shifts very nicely. If I am not accelerating or lift off on the gas about the time the 1-2 shift would happen there is a very noticeable clunk when is does shift to 2nd. I sound like it coming from the rear end in the form of a pinion "back lash snap", for the lack of a better term. Other word maybe the drive shaft slows quickly for a second and then resumes pushing the car forward. Its very prononced if letting of throttle around the 1-2 shift but is still noticeable even under slite accelerating. Never under moderate to hard accel.
Any thoughts before I ask the trans builder about it.
P.S. It has always done that since the rebuild.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir
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argentina-slantsixer
 Post subject:
PostPosted: Tue Nov 13, 2007 5:30 pm 
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Joined: Mon Jan 12, 2004 4:20 am
Posts: 2011
Location: Argentina
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my 904 did that. if I laid off the throttle just about the time it was about to shift froms 1st to 2nd, it would "clunk" on me. I believe this has something to do with engine increased performance

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Juan Ignacio Caino

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Romeo Furio
 Post subject: clunk
PostPosted: Wed Nov 14, 2007 3:55 pm 
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Turbo Slant 6

Joined: Thu Jan 04, 2007 6:38 pm
Posts: 878
Location: Boulder City Nevada
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Mine also, it could be that the rebuilder upped the line pressure along with your kickdown adjustment that can cause this. In one car we put the 5.0 lever, that one really snapped when you let off.
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emsvitil
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PostPosted: Wed Nov 14, 2007 4:28 pm 
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Joined: Thu May 12, 2005 11:50 pm
Posts: 6291
Location: So California
Car Model: 64 Plymouth Valiant
My stock engine and 904 do the 1-2 clunk...

I get it in the parking lot/ stuck in traffic speeds where you let off the gas when it wants to shift. (not all the time, just occassionally)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

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dank10fenny
 Post subject:
PostPosted: Thu Nov 15, 2007 12:15 pm 
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EFI Slant 6

Joined: Mon Nov 05, 2007 1:48 pm
Posts: 351
Location: PDX, OR
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well i know my clunk is rear end. when your coastin then your diff is on deccel. when governer pressure builds as speed increases it will make a 1-2 shift, throwing the diff in accel real quuick, makes a pretty cool noise... cept not...
im sure its not this, but just tossin this out there
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70Dart
 Post subject:
PostPosted: Tue Nov 27, 2007 9:47 am 
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Joined: Tue Aug 21, 2007 10:38 am
Posts: 49
Location: Antelope Valley, California, USA
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Actually thats what I was thinking, my dart does this too.
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dank10fenny
 Post subject:
PostPosted: Wed Nov 28, 2007 12:33 pm 
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EFI Slant 6

Joined: Mon Nov 05, 2007 1:48 pm
Posts: 351
Location: PDX, OR
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and those 7-1/4 really make a lot of noise, they just got too much play in them, ive heard of ghetto shimings the side gears and puttin a motorcyle valve spring in the carrier pin to tighten it. i just throw it down into secon on hills....
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