07jk wrangler 3.21 to 4.88
 

Hey guys, I know this has probably been done before but I’m just after some clarification.

2007 jk wrangler unlimited sport 4 door 6speed manual.

I’ve taken my wrangler to a shop to have some 4.88s installed. Now as far as I’m aware the 4.88s should fit straight into the rear even on the 3.21 carrier as they are one size fits all in the jk Dana 44? The front however needs a carrier replacement to the 3.73 and up in order for the 4.88s to fit in the wrangler Dana 30? I’m being told they can not do it because the housings need to be upgraded? I’m not a mechanic or anything but I have done a bit of research on it and from everything I’ve read it seems as though I have the right idea. I did purchase the new gears second hand but they were brand new in the box so I’m fairly confident that the gears are correct for the car. Initially I had tried to do the work myself but found it to much for me without the right tools but I had the rear 4.88s in and running smoothly apart from a bit of a whine due to incorrect shimming which is why I took it to the shop to have it done correctly. Just hoping someone could shed some light on this situation as I don’t want to pay for new housings if it dosnt need them.

Thanks guys.

From what I see after a quick google it does seem you are correct and you just need a carrier for the front. Might be worth asking why they think a new housing is required when everybody else just changes the carrier.

I’ve just rang them to reconfirm and there had been a mix up of information. The housings don’t need to be replaced they are saying both carriers need to be replaced. As far as I’m aware it should only be the front one that needs to be replaced to a 3.73 and up carrier and the rear should fit straight in. I can’t seem to find a 3.73 or 3.93 and up carrier or anything for the rear, only info stating that they all run the same size carrier. I’ve found 3.73 and up front carrier fir the Dana 30 on sbr off-road website but the shop is sceptical about me supplying my own parts and quoted me around $1000 for both carriers, does that seem right?

Sounds like you need a new workshop. If they can't figure this out then I would be worried about their workmanship. What you are doing is well documented and been done thousands of times around the world. The info you have is correct, nothing needs to be changed in the D44 and the D30 has a carrier break at 3.73 and up (so yes needs a new carrier).