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i just took out my aod tranny and try putting the c4 but the cross-member to the aod will not let the c4 tail end sit on it properly so do i need to get a c4 crossmember and does it matter what years and what kind if so? the tranny is a tci....:?::?::?:
 

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While I can't tell you which cross member to use, I can tell you IT IS ABSOLUTELY CRITICAL you get it right.

The wrong cross member means the tail housing is not sitting where it is supposed to and the drive line angles will be compromised.

My best advice is to re-install the original transmission with the original cross member and then take a measurement from the center line of the output shaft up to the tunnel and write down whatever that measurement is. When you do find a suitable cross member, mock it up with the new transmission and refer back to the measurement you got and be sure to set the tail housing of the new transmission at the exact same height as the old one. This will ensure the drive line angles stay in tact and you don't have a vibration.

If the new transmission is a different length than the old one, you will have to adjust your measurements accordingly.

Ideally on a passenger car, you want to maintain between 2* and 3* for angles. They also need to be equal but opposite, in other words, if the angle at the junction between the drive shaft and the tail housing is a +2*, then the angle at junction of the drive shaft and pinion yoke needs to be a -2*. They can vary by up to 1/2* but no more than that.

You can easily measure the angles with an angle finder and you can find them at Sears, Home Depot, Harbor Freight or any good hardware store.

I start by making sure the car is sitting at ride height and then get a reading from the bottom of the tail housing near the end of the transmission (call this reading "A"). Next, get a reading from the middle of the driveshaft and call this "B". Finally, with the pinion yoke turned vertically, place a socket directly on the rear u-joint cap and get a reading from the socket, call this one "C"..

Now take the difference between A and B and this equals the front u-joint working angle. Next, take the difference between C and B and this equals the rear u-joint working angle. It is these 2 working angles that need to be equal but opposite like I explained above.`

If you need more help on this, let me know. :bigthumbsup
 

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Either cut the welds so the member slides or spin it 180* which ever works. your aod crossmember works just fine
 

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I had the same problem when I instaled my C-4 into my '89. I read all the advice about moving the mounts forward fro the cross body member. What I did was to weld a piece of steel plate to my original mount on the cross body memebr and drillout holes on the plate where the bolts run up to the transmission. This amy not be real clear but it worked great. I was able to set my pinion angle to 2.5*. All is well.
 
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