I got a 02 almn DS for almost free. So I went in to swap them out and the u joint to my diff is bigger and longer. I thought it was a bolt up. I do have a 9bolt do that mean any thing. What part # should I use I will grab one at the parts store. I will upload pic

 

 

Looks like you probably have a 1330 series u-joint on the old steel driveshaft, whereas the aluminum shaft probably uses the 1310 series, which is narrower across. You might have to get a conversion style u-joint that's the width of a 1330 one way, and 1310 width the other way. Here's the Neapco part# for the 1310/1330 conversion u-joint (#1-0134). I found a couple of good deals for them on Ebay. The first one doesn't list the brand, but it's $19.95 with free shipping: http://www.ebay.com/itm/1310-1330-U-Joint-Universal-Chevy-Ford-Jeep-conversion-/200631074342?pt=Motors_Car_Truck_Parts_Accessories&hash=item2eb68b3e26&vxp=mtr The second one I found is actually a Spicer brand, which is what I'd recommend using. It's $24.95 w/free shipping: http://www.ebay.com/itm/5-134X-Dana-Spicer-Conversion-U-Joint-1310-1330-/370798319375?pt=Motors_Car_Truck_Parts_Accessories&hash=item56554d570f&vxp=mtr. I had to buy one of these when I put a Tremec 5 speed in my 69 Camaro because the stock, Chevy driveshaft required the 1310 width, and the slip yoke for the Tremec was the 1330 width. The conversion u-joint worked like a charm! You might want to measure just to be sure it's 1310/1330, and not 1310/1350, but I'll bet it's 1310/1330. Hope this helps.

 

1310 is the mm right

 

No, those numbers are just the u-joint series. A 1310 u-joint will measure 3.219 inches wide, and the bearing caps are 1.063 inches in diameter. A 1330 u-joint measures 3.622 in width, and it's bearing caps are also 1.063 diameter. I couldn't find the width measurment for the 1350 series, but I highly doubt you have that series anyways. If it is a 1350 width, it'll be wider than 3.622, and I also think the 1350 bearing caps are a bigger diameter than 1.063. Btw, the width is measured from the flat part of one cap to the flat part of the other cap IIRC. Hope this helps!

 

Ok I mic it out and the alumn is a 1310 and the old one must be 1350 with cap at 1.130 and Lth at 3.670

 

Still not the right stuff. It just slide side to side. The old u joint had c clips on the inside so it don't move on the diff. So it can center itself.

 

Sounds like your best option is gonna be to press the u-joint out of your old driveshaft and take it with you to the parts store and just have them use it to match up a new replacement one for you.

 

That's where I work (ed) and I had them with me. The old caps don't fit the new ds, and the new caps don't fit on the old u/j. This is crazy I'm sure I will think of some thing. I think if I put the 1310 u/j in and put the 1330/50 caps to the diff it will work.

 

Scary! I too bought an aluminum driveshaft to slip in to my 86 one day!!! I will be interested to hear what the solution is here.....

 

Yeah, I feel your pain, I hate playing the "u-joint game" too! Lol. I'm almost sure there's a u-joint made by one of the companies that actually works, but it's a PITA to find the right part number! If you go to Neapco's website they have a cross-reference chart for u-joints that includes the measurements and the part numbers. They even have conversion u-joints listed on there. That's how I found the correct conversion u-joint when I put a Tremec in my 69 Camaro. My driveshaft required a 1310 and the Tremec slip yoke required a 1330, so it had to be 1310 in one direction and 1330 the other direction. So yeah, go to Neapco.com and take a look at that u-joint cross-reference chart. Then you can match up your measurements with an actual part number.