S13 Drivetrain Slop

M

Minimoke

Member
Hey all,
My S13's got 150k miles on the clock and everything felt a bit tired, especially a large amount of movement when prodding the throttle. Was like the engine and box were banging back and fourth a few inches. I've recently changed the engine and box mounts for Nismo ones and the rear subframe is temporarily on locking collars, but I'm still getting some slop and noticeable wheel hop on launches. The viscous diff is tired and I haven't checked the bushings, is that going to be my issue? It's also whining so it has to come out anyway....I can't seem to find any options for uprated rubber diff bushings, only really finding poly or solid which I'm not sure I want on a road car.

On a separate issue, my alignment is arrow straight and on smooth roads I get zero wheel judder. If the road is less than perfect the wheel shakes as if the tracking was noticeably out. Tired rack/bushings?

Thanks in advance for any advice.
 
Yep probably all the bushes are perished and ready to be replaced.

The stock ones were pretty soft to begin with so when they get tired and worn there is a noticeable amount of play and slop in the chassis.
 
r3k1355 said:
Yep probably all the bushes are perished and ready to be replaced.

The stock ones were pretty soft to begin with so when they get tired and worn there is a noticeable amount of play and slop in the chassis.
Click to expand...


Hey, cheers for the reply. Am I right in saying that getting the diff bushings out with the subframe in the car is going to be a RIGHT pain in the arse? Are they the same kinda thing as the subframe bushings? I need to change them too, so I can see a subframe drop in my not too distant future....
 
Minimoke said:
Hey, cheers for the reply. Am I right in saying that getting the diff bushings out with the subframe in the car is going to be a RIGHT pain in the arse? Are they the same kinda thing as the subframe bushings? I need to change them too, so I can see a subframe drop in my not too distant future....
Click to expand...

Drop the lot.

Are you going to rebush the stock arms or replace them?
Hardrace do bushed arms, stiffer rubber obviously. Bit nicer than polybushes on the road.
 
BenRice said:
What suspension is in it?
Click to expand...

HSD Monopro coilies, Hardrace hardened rubber front tension, rear camber, rear toe, rear tension, Nismo LCA's.

r3k1355 said:
Drop the lot.

Are you going to rebush the stock arms or replace them?
Hardrace do bushed arms, stiffer rubber obviously. Bit nicer than polybushes on the road.
Click to expand...

All the arms are the stiff rubber Hardrace yeah, so it's just the subframe and diff really. Looks like Hardrace do hardened rubber for the subframe but I can't find the same for the diff....
 
Rear end for reference. Got the car dialled in at Garage D, they told me the subframe bushes were shot so they added the collars as a temp fix. I never got the diff ones looked at.
20180824_133536.jpg
 
BenRice said:
Gktech do poly bushes for subframe too:

https://au.gktech.com/products/diff...rame-bushes/polyurethane-rear-subframe-bushes

IIRC the diff is solid mounted to the subframe on S13's (2 bolts either side of the snout and 4 bolts from the diff's rear cover into the subframe). S14 diff's are bushed front and rear
Click to expand...

Ah I see, so they really shouldn't be the issue then. If the subframe has locking collars then it shouldn't be able to move right? Unless it's slop in the actual diff but it feels too much for that. Running out of ideas....
 
Also noticed your rear knuckle still has the stock bushes in?

If stiffening up the dampers doesn't reduce/eliminate the wheel hop I'd swap the knuckle bushes and subframe bushes with poly replacements

If that doesn't work then something must be binding somewhere, possibly due to an old accident. At that point it's new subframe time
 
BenRice said:
How stiff do you have the dampers set?
Click to expand...
Not overly stiff, probably 5 or 6 out of 14 on the dampener setting. Not running too high pressure in the rears either. The wheel hop is one thing, it's the noticeable slop when touching/coming off of the throttle that's concerning me more.
 
BenRice said:
Also noticed your rear knuckle still has the stock bushes in?

If stiffening up the dampers doesn't reduce/eliminate the wheel hop I'd swap the knuckle bushes and subframe bushes with poly replacements

If that doesn't work then something must be binding somewhere, possibly due to an old accident. At that point it's new subframe time
Click to expand...
Thanks for the tips man, appreciate it. I'll do a bit of fault finding when I get a chance. I can't help think the two issues are linked at the moment.
 
Huh. After a long Google it appears the diff can cause a lot of issues like my drivetrain movement. It does have 150k on it I suppose....Makes it easier to justify a Kaaz Super Q to myself....
 
My S13 does it, when you apply throttle theres a quick clunk as everything is put under load and if I put the clutch in sometimes it does it - i've put it down to my diff being fucked but can't afford a rebuild at the mo so just hoping it lasts!
 
Re: wheel hop - try setting the dampers to 80% hard and see what you get

Re: slop. What are you comparing it to? Have you come out of a new(er) car? Things like the driveshaft and axles all have joints that can load and unload which can cause delays. I'd give it a once-over but wouldn't be too bothered tbh. It's a 90's Nissan doing 90's Nissan things.
 
I'll give those settings a go mate, cheers.

As for the slop it's not in comparison to other cars, is just noticeable knocks and looseness. Like something is turning half a turn before it engages. And then going back and forth a few inches. Isn't stuff I got with my haggard old E36 with a welder. Will get under there when I get a chance and unbolt the prop from the diff. See how much slop there is.
 
Righto, well if your comparison is an E36 with a welder then the slop must be significant

With the rear in the air, grab one wheel and rotate it forward and back. Take note of how much your wheel is turning compared to your axle, and how far it needs to turn before it starts moving the stub axle out of the diff.

If that's "reasonably tight" (there will always be a little slop in the axle CV's) then grab the driveshaft near the gearbox and turn that back and forth by hand with the handbrake on, noting how much slop there is in the driveshaft joints before the diff input starts turning. While you're under there, check the driveshaft hanger bushing in the middle. If the rubber has been demo'ed completely then that could be the cause (especially if the gearbox has been flopping round on a shot mount).

The final thing would be the diff backlash - if the diff input / pinion is moving excessively before the axles move then the issue is with the diff backlash. This means you either need to reset it with more shims behind the pinion / either end of the pumpkin or find a diff with tighter clearances (easier/cheaper).
 
Last edited:
Thanks man, really appreciate your tips on this. Since the diff is whining more than it used to I've got a feeling it's gonna be that, but the prop hanger bushing is also a good shout. Since it's an old diff and whining anyway I was considering sticking some shims in there, for the sake of £15 a an afternoon's work. Before I shell out for a 1.5 way! Cheers again.
 
You must log in or register to reply here.
Back
Top