Nismo Diff Clunks After Swap

[dongoesby]

The s14 just had a sr swapped, and for the past 2 weeks, I have been suffering with drivetrain problems. Let me explain the symptoms. When start moving from a stop with a little gas, the rear would knock/clunk a least a little bit before gaining smoothly into speed. Sometimes I have to give little gas, then immediately step on the clutch to avoid that clunk, then when the car crawls forward slowly, then i can gas it to gain speed without clunking. Here is the violent part: If I start without gas by simply letting go the clutch slowly, the car would violently wanted to go forward then stop then jump forward then stop. Basically, at such low rpm, instead the engine dies, it would jump back and forth violently.

This symptom happens again when I'm coming to stop in gear, at low rpm anywhere from 200 to 800, it would start clunking violently. If i let go of the clutch, it would go away. Or if i give it gas, it would go away.

A similar symptoms happens but a lot more minor when I'm, again, at low rpm, shifting from 1st to 2nd, or 2nd to 3rd, or 3rd to 4th, it would have a very minor clunk feel. It is very minor. But if I'm gentle on the gas (very little), it won't happens. It happens only if I give more gas at low rpm (1800~2800).

Current setup:
Nismo engine and tranny mounts
Exedy lightweight flywheel
Local custom clutch kit (kelvar disc w/ dual diaprahragm pp)
New factory TOB
New nismo pivot ball
2 years nismo 2way diff (used no problem with KA before, now with new Motou oil)
1 year old stance gr pro (no problem with KA before)
stock old subframe and diff rubber bushings (don't give problem with KA before)
1 minor leak axle (driver side)
1 uneven wear tire (due to excessive negative camber at driver side, inner side is flat)
possible different pressure on tires (car up in the air for 2 month during swap)

Before the swap, I didn't have problem with startoff or shifting at low rpm. I'm positive that I have tranny mounts installed correctly, tranny bracket tight, driveshaft bolt tight and everything.

Any support is welcome!

[karl wasabi]

You know that 2-way diffs are supposed to clunk right? Like it's crazy how much 2-ways clunk. If you didn't use specific LSD fluid when changing the diff fluid the diff will clunk a lot more than you are probably used to. That's the only thing I can think of if everything is all new and bolted up correctly.

[dongoesby]

i don't think it does not suppose to clunk when i start moving from a stop in 1st gear.

before the swap, it didn't with my KA for the past 2 years. Besides, the Motul diff fluid is used because it minimize the clunking noise.

[MrChow]

i don't think it does not suppose to clunk when i start moving from a stop in 1st gear.

before the swap, it didn't with my KA for the past 2 years. Besides, the Motul diff fluid is used because it minimize the clunking noise.
Question... Do you mean in a turn or in a straight line??

Yes Motul help minimize clunking noise in Nismo LSD. It a god sent for me.

Double check all the bolts down there. I had someone have a problem like that and it was from drive shaft to diff bolt being lose.

[nathanong87]

i don't think it does not suppose to clunk when i start moving from a stop in 1st gear.

before the swap, it didn't with my KA for the past 2 years. Besides, the Motul diff fluid is used because it minimize the clunking noise.

if u are turning from a stop -> 1st gear, i'd expect a clunk. my kaaz 2 way is very noisy and it uses the recommended kaaz oil and was broken in properly etc etc. my friend used to have an ATS on his s13 and THAT sounded broken everytime he turned LOL.

cliffs notes: clunkin, it's just a part of having a 2 way

[94_240sx]

I have s15 Helical and it clunks too. It acts exactly same as OP stated, but as bad as his. It doesn't do that everytime though. I think my case is different. I think I didn't shim it properly, so there's a little bit of play. What do you call it? It's where the gear from drivershaft meets gear in diff.

[clark]

I have s15 Helical and it clunks too. It acts exactly same as OP stated, but as bad as his. It doesn't do that everytime though. I think my case is different. I think I didn't shim it properly, so there's a little bit of play. What do you call it? It's where the gear from drivershaft meets gear in diff.

it's called backlash. there is also something called "tooth pattern"

[anton1o]

Its kind of hard to listen to the clunk of it, but make sure you are running the correct fluid in the diff, Nismo Diff oil with nismo, Kaaz diff oil with Kaaz you wouldnt belive the amount of difference we had changing diff oil from Castrol to KAAZ the sound is still loud and still clunks but its much quiter then Castrol.

[dongoesby]

Question... Do you mean in a turn or in a straight line??

Yes Motul help minimize clunking noise in Nismo LSD. It a god sent for me.

Double check all the bolts down there. I had someone have a problem like that and it was from drive shaft to diff bolt being lose.

No, not starting from a turn. Every single stop at a light or sign, it clunks/chatter noticeably while I shift into 1st and give gentle gas. It would be 10 times worse if I just let go of the clutch without any gas.

When I did my swap, I only disconnected the driveshaft at the front portion. I didn't touch the bolts that connecting the shaft to diff. I guess I don't have to deal with the driveshaft alignment in this case?


I have been driving with this nismo diff for 2 years and i know when it supposes to make clunk and when it shouldn't. Now it clunks at a straight line.

[Teknolust72]

I wonder if you have the correct driveshaft? Wrong length of driveshaft would cause the diff to behave oddly in a straight line

[swayray]

if all of that isn't the problem then the last thing that could possibly go wrong would be the teeth on the ring or pinion already being chewed out which would cause the clunking on a straight line. Try putting a friction modifier additive and see if the noise goes away or settles down. We have BG's friction modifier in stock if you want to try it:

The Nismo Shop : West Covina Nissan : BG LSII LSD Additive (http://www.thenismoshop.com/ikorb.php?func=catalog&category_id=1259&product_id=1530)

[MELLO*SOS]

it's called backlash. there is also something called "tooth pattern"

Yup I bet the OP problem is improper backlash on the diff.

You can test with the car in the air, set the ebrake. Put trans in neutral. Spin driveshaft with your hands. You'll notice you can spin the driveshaft a little in both directions then there is a clunk as the diff teeth mate. This slack results in the clunk.

There's another huge thread on here somewhere where we were talking about this, I think Clark was in on that one too?

Probably best bet is to take the pumpkin out, take it to a driveline shop and have them reshim it to set the backlash properly.

I have a similar issue in my s13/kaaz, it's annoying and I should probably deal with it sooner than later.

GL

[94_240sx]

it's called backlash. there is also something called "tooth pattern"

Yeah, that's it. I remember now. I tried my best to install it right, but there was a little play when I turn it with my hand. I guess that's causing it.

[Edgar]

My Kazz kinda use to be really loud and then I solved all my problems kinda by adding Motul P90A to my diff which I think already has friction modifier.

Have you done anything to your subframe? I feel some movement at times in my car and I only have Kazama collars, i'm changing them to solid over the winter and see if that helps.

What kind of clutch do you run?

[Teknolust72]

but the pumpkin wasnt touched during his motor swap? would backlash be an issue if it was working fine 2-3 weeks ago?

[I LUV MY S13]

idk bro i dont think its your diff...double chek your driveshaft

[Sonic Motor]

i heard about a reeeal funny story about this from a past 350z owner. Real funny.
But that is for another time, another thread hahah

We sell redline LSD additive. Its real good. Gets rid of aggressive locking.

[s13 drifta]

Your rear end is clunking because you need new subframe bushings or collars to eliminate the subframe from moving.

[MELLO*SOS]

but the pumpkin wasnt touched during his motor swap? would backlash be an issue if it was working fine 2-3 weeks ago?

Sorry, I thought he installed the diff himself into the pumpkin. OP still try the test I said, rotate the d/s by hand and see if you can make the diff clunk when the teeth engage. If so, backlash. If there's not much slack there it could just be due to bushings and the other shit people are suggesting in here. Subframe/diff noises can be cause by tons of random shit, GL hope you get it fixed.

[dongoesby]

Yup I bet the OP problem is improper backlash on the diff.

You can test with the car in the air, set the ebrake. Put trans in neutral. Spin driveshaft with your hands. You'll notice you can spin the driveshaft a little in both directions then there is a clunk as the diff teeth mate. This slack results in the clunk.

There's another huge thread on here somewhere where we were talking about this, I think Clark was in on that one too?

Probably best bet is to take the pumpkin out, take it to a driveline shop and have them reshim it to set the backlash properly.

I have a similar issue in my s13/kaaz, it's annoying and I should probably deal with it sooner than later.

GL

sorry for the late reply. It has been raining lately. I just finished testing the driveshaft with following method mentioned above.

I locked the ebrake, went under my car and turned the driveshaft by hand. Yes, there is a bit free play and it makes a clunk (or "bung") sound pretty noticeably. The "bung" sound doesn't happen on both direction of the freeplay. It "bungs" only when I turn to one direction.

Why would I have backlash since it was first fine with my KA 3 weeks ago. Does that necessary related to the increased torque from SR or is that the diff is getting old?

[dongoesby]

My Kazz kinda use to be really loud and then I solved all my problems kinda by adding Motul P90A to my diff which I think already has friction modifier.

Have you done anything to your subframe? I feel some movement at times in my car and I only have Kazama collars, i'm changing them to solid over the winter and see if that helps.

What kind of clutch do you run?

I'm running with a customized clutch done by a local Norcal shop calls Illegal Garage. It has a kelvar clutch disc and a dual diaphragm pp.

My subframe is old with stock rubber. I have yet to have time to install the SPL alum bushing. However, before the SR swap, even with stock rubber, my old KA didn't have that clunking sound.

I'm pretty affirmative that the driveshaft bolts are tightened to factory spec.

[clark]

I'm running with a customized clutch done by a local Norcal shop calls Illegal Garage. It has a kelvar clutch disc and a dual diaphragm pp.

My subframe is old with stock rubber. I have yet to have time to install the SPL alum bushing. However, before the SR swap, even with stock rubber, my old KA didn't have that clunking sound.

I'm pretty affirmative that the driveshaft bolts are tightened to factory spec.

how much gap do you have between your tranny snout and the drive shaft.

i'm referring to how much give your slip yoke has. inches/mm would be an acceptable form of measurement. or take picture with a dollar bill yall.

donegoesby, i mean sure, youre subframe bushings are shot, but at this point, anyone who comes on here and says "durr it's your subframe bushings" is a douche.

i fully understand your problem, because i currently have a similar problem.

i am going to be experimenting by putting back a stock driveshaft. i personally have a feeling my driveshaft is too long. i have about 1/8th inch of play between my tranny snout and hte driveshaft. so that's 1/8th inch of slip for the yoke. i know that can't be the right amount.

can anyone chime in on the correct amount of play there should be for the slip yoke? is it 1 inch? 3/4 of an inch?

[ziptiemcfly]

http://zilvia.net/f/members/carparthookup.html buy his redline diff stuff my tomei 2way was klunking and i put that plus lucas gear oil and my 2ways quite now