hybrid q45 diff swap. which housing and why?

[compactfean]

So after many months of gathering parts and researching I am finally ready to tear into both of my diffs. I have a stock 240 diff and my q45 diff swap. I, want to use the 240 ring and pinion but am wondering if the q45 or the 240 housing will make the swap any easier. Any experience in the matter is more than welcome.

[moso]

when i swapped my j30 diff into my 240 it was to keep the same ring and pinion. basically it was less work to use the original housing because i didnt have to remove the pinion gear. the same would be true for the q45 diff swap, and we all know the housing is built like a bomb shelter so no worries about blowing it up.

[compactfean]

Did you run in to any issues with readjusting bearing load, backlash, or output shaft length?

[moso]

nope, its as quiet as can be too. I cant remember if i used the shims and bearings that were in the open diff or the vlsd but whatever it was it was the "obvious choice" once i got them open. If i remember correctly the center sections of the open and vlsd were the same length so i used the bearings and spacers from the open diff. the passenger side stub axle didnt sit flush, and it needed persuaded into place (dead blow hammer). After 13k miles i still have no issues with it and it will still roast both tires, no problem.

[compactfean]

Dang. if the center sections are the same width than yeah that should work perfect. I had to do the same thing when I shimmed the j30 that is in my car right now (deadblow) and that still didn't work for me. I had to open it back up and loosen the ring gear bolts, stab the output shaft in to line everything back up and tighten the ring gear bolts with the shaft in it. Then pull the shaft out and put the assembly in and put everything back together. I have an abs one piece driveshaft. You think switching to a non-abs diff will have any effect on the abs driveshaft? This will only be until I have enough money for the vg trans swap kit.

[compactfean]

A also did you shim, the vlsd and what thickness? I shimmed my j30 with the 1 shim (the thick one nissan sells) and makes my car chirp around corners and was a major pita to get the diff back together.

[moso]

the difference in length of the stock driveshafts is less than one inch. i cannot see how using the shorter shaft in the longer application could hurt. i also used the 0.80mm shim, it was a pita to get back togeather. i fortunately had the foresight to assemble it with the stub in place. it definitely chirps around corners, still.

[compactfean]

The .80,on top of the stock one? Im trying to see how much I want to shim this setup. Lol. If I remember right I put the 1.0 mm on to of the stock shim..... I won't be doing that again. And if .80 on top of stock still chirps, I might go even smaller then that.

[moso]

yup on top of the stock shim. i had thought about disassembling the unit and measuring the stock shim and ordering a single shim about .040 or .060 thicker than the stock one and running only one shim. I simply didnt have the time.

[compactfean]

Alright cool. Yeah ill probably try the .040 thicker, just because the reassembly with the thick as shim is still fresh in my mind. Not to mention I doubt the vlsd from a q45 was ever used to its full potential. Maybe have the best of both worlds too! If I could have full lock on acceleration only, ill be very happy. I will be installing uprights, struts, and a bigger sway bar when I am ready for the rear end but I'll get back to ya and let you know how the .40 goes.

[compactfean]

Small update. After taking apart the q45 to sell the ring and pinion, find that the q45 bearings look similar. I looked up the part number for the bearings for the 240 and q45 and they are the same bearings so I will be using the bearings and races that come with the q45 cartridge.

[compactfean]

Ok, so I used the 240 housing (saved me a lot of work because I didn't have to deal with the pinion), with the 240 ring gear and bearing spacers. I used the q45 center section, bearings and races. Backlash feals identical to how it was before but I'll double check later with a gauge. My question is, notice the right shaft sticks out further than it should. The seal still seals the shaft but is definately further out. I've heard of people cutting the shaft shorter but I don't understand how that would even make a difference because the snap ring in the vlsd controls output shaft depth and once it snaps into place, that's how far it goes in..... So????

[moso]

I run mine with the gap with absolutely no ill effects. I have just over 14k on it and its first run was a straight through from new orleans LA to cleveland OH. I find myself thanking me for doing the j30 version of this swap.

[compactfean]

Everything went really smooth. I had to use the .80 shim because that's the smallest nissan has. If I don't like it though, at least I know exactly what is in it to change later. I argued with my father in law about the gap like an hour... Needless to say there was no convincing him it was ok. I think I'm just gonna run with it.