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83 904T shudder at 35-40 MPH
https://slantsix.org/forum/viewtopic.php?t=39894		 Page 2 of 3
Author:  Reed [ Wed Apr 21, 2010 8:13 am ]
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We removed the huge transmission cooler and went back to just the stock cooler in the bottom of the radiator. We ordered that spring kit and my brother is going to try and find one of the dealer springs as well. If all goes well, we will install the spring this weekend. I'll report back what happens.

I really hope this spring solves the problem since I don't want to swap out ANOTHER transmission on this van. Four in three years is plenty for me.
Author:  Doc [ Wed Apr 21, 2010 8:24 am ]
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Try to get ahold of a 200 psi oil pressure gauge and check the line pressure.
Factory spec for the 904s is 155 to 165 psi and many used transmissions I check are usually below that. (I readjust them to the high side of the spec.)
Keeping the main line pressure to spec. helps all-around trans preformance and longevity.

Note: line pressure is increased by turning the adjustment screw counter-clockwise... one turn is about a 10 psi change in pressure.
DD
Author:  Reed [ Wed Apr 21, 2010 9:45 am ]
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Thanks Doc! I definitely will get a gauge and check the line pressure. I adjusted the line pressure screw out as per the instructions that came with the shift kit, but I have no idea what the line pressure is at this point. Time to check and make sure all is within spec.
Author:  Eric W [ Wed Apr 21, 2010 9:57 am ]
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Reed, is the line pressure adjustment simular to the adjusting procedure outlined in the magazine artical you showed me and did on the Satellite's transmission, and what I did on the 5th?
Author:  Reed [ Wed Apr 21, 2010 10:42 am ]
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Yes. It is the little allen head screw on the side of the valve body.
Author:  Doc [ Wed Apr 21, 2010 12:00 pm ]
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You have to cut the allen wrench short to do the adjustment while the VB is still bolted into the trans case.
DD

Image
Author:  Reed [ Wed Apr 21, 2010 1:44 pm ]
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Thanks. I will actually be pulling the valve body to replace the lockup spring, but I will also cut down an allen wrench so I can adjust the line pressure without pulling the valve body.
Author:  Reed [ Wed Apr 21, 2010 2:29 pm ]
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UPDATE: My brother was actually able to order the spring replacement kit through the dealer. They found one somewhere in the midwest, so maybe there are a few of these factory kits still out there. :)
Author:  Reed [ Sat Apr 24, 2010 4:10 pm ]
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Quick update: The factory replacement spring arrived but the eBay kit did not. Makes me mad since the eBay springs are shipping from Oregon and I am in Washington, but the factory springs shipped here out of Kansas. :?

Anyway, we will replace the lock-up spring with the factory replacement spring tomorrow and see if that makes a difference. I'll report back with results.
Author:  Eric W [ Sat Apr 24, 2010 6:20 pm ]
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Reed, did you get the TF-TC kit? I think there is a place in Kent to get those looking at their web site..Just sayin.. :wink:
Author:  Reed [ Sun Apr 25, 2010 1:09 am ]
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Yep, we ordered the TF-TC kit off of eBay. Figures that there is a place close by that stocks them. :roll: Oh well. We have the parts we need to see if the problem really is the torque converter lockup spring, so we will press ahead.
Author:  Reed [ Sun Apr 25, 2010 2:31 pm ]
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QUICK UPDATE:

ImageImageImageImage
Author:  Joshie225 [ Sun Apr 25, 2010 6:19 pm ]
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Really now? Care to fill us in on the details?
Author:  Reed [ Sun Apr 25, 2010 7:25 pm ]
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Whew, sorry, just had to vent.

Turns out the lock-up spring in the valve body was already some kind of aftermarket spring- it was longer and stiffer than the Mopar replacement spring we ordered. So, we decided to leave the valve body out that had the shift kit and the big spring and install a totally stock valve body with no shift kit or special lock-up spring. The shudder didn't go away and the transmission shifted like poo.

After reading through the diagnosis section in my 84 FSM, I decided either the torque converter was bad or there was something much more serious wrong with the transmission. So we swapped valve bodies back to the one with the shift kit and aftermarket lockup spring, switch torque converters from the allegedly rebuilt unit to a stock torque converter out of a 79 Aspen transmission, and bolted it all back up. Success! Image Turns out the "remanufactured" torque converter was dead and causing the problem. The shudder is gone and the van drives much better.

So, now I have three of the factory Mopar stiffer lock-up springs and an extra TF-TC kit on the way. :roll:
Author:  Eric W [ Mon Apr 26, 2010 12:37 am ]
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I'll buy one of the springs from you..or maybe the whole kit.

Edit: I forgot, you can use the kit on you van!! 8)
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