Q45 diff.

[Piston1047]

Ok guys, I think my diff. or a part of it is dying or dead. roaring during acceleration and at it makes a whoov whoov whoov sound like a bad tire when slowly gliding in drive. After researching a little i realize that a new diff. is probably 2/3rds the value of my car. I just wanted to get an opinion on other/better/CHEAPER options. i have read around nico and q45.org and i see that the Y33 can use a Z32 one and I know the G50 is a R200v. Thanks folks.

[maxnix]

G50 has the six bolt flange. TCS has different differential accessories also.

What is the car worthto you?

[Q45tech]

We change many diffs on high mileage Q/J......find a low mileage junkyard one................~~$300 the newer year the better. Only 90-96 will fit.

Replaced mine at 225k.

[goody90q45]

There's one on ebay right now for $24 (with no bids yet) and $110 shipping, from a 94Q with 130000 miles.

[Q45CALIBER]

What is the car worthto you?

My thoughts exactly.

[guadofreak]

the diff in mine was replaced around 100K with a junkyard unit. I now have 170K on it. Seems to be holding up. I guses some are just prone to dying.

[JohnPa]

We change many diffs on high mileage Q/J......find a low mileage junkyard one................~~$300 the newer year the better. Only 90-96 will fit.

Replaced mine at 225k.

Since the topic is replacement rear ends, here's an idea I've been playing with. I would like the 4:08 rear end in my 90 Q45t, but haven't figured out how to make the speedometer work even after searching all of the posts. What about using the differential out of the 97-01 Q which splits the difference between the 3:54 and 4:08 ratios, but should bolt right up. Then, and here's the real question, fit the speedometer sending unit from the newer transmission to the older model transmission.

What do you think? Will this work?

Just an idea.............John

[sijoko]

Since the topic is replacement rear ends, here's an idea I've been playing with. I would like the 4:08 rear end in my 90 Q45t, but haven't figured out how to make the speedometer work even after searching all of the posts. What about using the differential out of the 97-01 Q which splits the difference between the 3:54 and 4:08 ratios, but should bolt right up. Then, and here's the real question, fit the speedometer sending unit from the newer transmission to the older model transmission.

What do you think? Will this work?

Just an idea.............John

The 90-96 differential has the 6 bolt flanges. If I am correct, the 97-01 Q diff has 5 bolt flanges.

As far as the speedo calibration for the 4.08, I am using the plastic gear for a 3.9 ratio. Once you get past this size, the plastic gear will no longer fit on the VSS of our cars.

So I just went with the 3.9 VSS gear. The speedo reads a bit optimistic, less than 5%.

If you run taller tires in the rear, then this would work out perfect.

[RobertsnewQ]

1. later diff (Y33) does not bolt up. It's the same as 300zx2. Speed sender isn't the problem - it's the speedometer that tells everything else how fast the car is going. The Nissan system uses the speedometer in the dash as the "head" - it calculates the speed based on the speed sensor & known axle ratio. Maybe you could use a R32 or Z32 speedo mechanism? I've never looked at it, but it might be possible to modify the speedometer to send the proper signal.

[elwesso]

you should be able to use that little yellow box.. but the VSS swap is the easiest IMO... the difference between 3.9x (in the J30) and 4.08 isnt much to cause that big of an issue...

itd be useless to go to a 3.69 diff... thats a waste of money and time IMO!

[DrewQ45]

We change many diffs on high mileage Q/J......find a low mileage junkyard one................~~$300 the newer year the better. Only 90-96 will fit.

Replaced mine at 225k.

Did you replace yours out of necessity, or proactive maintenance? Wonder how long mine will last. Pretty quiet so far (198K)

Had my diff fluid changed years ago at T-3 when I did my guides (you might remember Tech) and changed it again a few months ago to synthetic. Hopefully that might drop the operating temp a few degrees. I keep coming across people who tell me I don't need to change diff fluid...ever! I tell em.... "sure...cause Nissan made the drain and fill plugs just for show!"

Boy that stuff stinks!!! That magnet does a pretty darned good job of catching particles.

[redmanfx]

Since the topic is replacement rear ends, here's an idea I've been playing with. I would like the 4:08 rear end in my 90 Q45t, What do you think? Will this work?

Just an idea.............John

red

[JohnPa]

you should be able to use that little yellow box.. but the VSS swap is the easiest IMO... the difference between 3.9x (in the J30) and 4.08 isnt much to cause that big of an issue...

OK, help this novice out here. What is the 'little yellow box' and the "VSS" you are referring to? Sounds like this can be done if I get the right parts!

Thanks.............John

[elwesso]

yellow box is a vehicle speed interpriter.. rob tried it but it didnt work..

VSS=vehicle speed sensor

[JohnPa]

Wes, one last question on this issue. Does the J30 have a 3.9:1 ratio differential? If so, why not use that in an early Q and the speedo gear mentioned above to get the speedo to register correctly?

Thanks..............John

[dousan_pg]

yes j30 is 3.916

[CVS]

Hey "Q45CALIBER",

Where did you get those BMW style "Angel Eyes" on your headlights?They look the biz! Ya da boz man! How much did it set you back? I presume you installed them yourself?Hope they are available for order online as i am in Australia.

RegardsCVS

Edit: piston1047, Oops sorry for accidentally hijacking this thread... Did not see q45calibre's "Angel Eyes" thread(s) until he pointed them out. Been 12 months since i came back to this forum forgot how it worked. Thats why i shall forever remain a "newbie"...

CVS

Modified by CVS at 8:04 PM 4/10/2006
Modified by CVS at 8:11 PM 4/10/2006

[elwesso]

Wes, one last question on this issue. Does the J30 have a 3.9:1 ratio differential? If so, why not use that in an early Q and the speedo gear mentioned above to get the speedo to register correctly?

Thanks..............John

It doesnt bolt up.. it uses the 6 bolt flanges with 3 groups of 2 instead of 6 evenly spaced

[Q45CALIBER]

Hey "Q45CALIBER",

Where did you get those BMW style "Angel Eyes" on your headlights?They look the biz! Ya da boz man! How much did it set you back? I presume you installed them yourself?Hope they are available for order online as i am in Australia.

RegardsCVS

Thanks CVS. Here you go.

zerothread?id=164207

zerothread?id=165785

Wes-I think I read on e of the post you we saying that you dont have that many dead spots accelerating with most of the mods you have done. Is there any reason you have not put the 4.08 diff on your car?

Trying to decside if this is what I am going to do. I guess I will not be trying to take the car to its top speed that often.

[elwesso]

Wes-I think I read on e of the post you we saying that you dont have that many dead spots accelerating with most of the mods you have done. Is there any reason you have not put the 4.08 diff on your car?

Trying to decside if this is what I am going to do. I guess I will not be trying to take the car to its top speed that often.

I guess you could say i just havent gotten around to it. I was going to buy a diff last fall, but i never did it because by the time i was ready to buy it was almost winter. Dont need the 4.08 in the winter!

Thats basically the only reason i havent done it yet!