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Clunk diagnosis continues... Requesting a small video from Quaife/MFactory folks

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#1
Hello everyone,

So I'm continuing figuring out why the gearbox w/ Quaife in it clunks violently when shifting 1->2 and between forward and reverse gears (for instance second/reverse). Scheduled an appointment with Ford to double check the fluid level and bleed the clutch etc etc, but meanwhile trying to do whatever small tests I can do myself.

Today I drove around for a bit to warm everything up (which is when the clunk happens), lifted one wheel up (other is on the ground), put the car in neutral and rocked the lifted one back and forth and it sounds like this:

View: https://www.youtube.com/watch?v=lxWOq8K4gnY


If you have Quaife (or Mfactory) diff in I would greatly appreciate it if you tell me whether your car sounds similar when you do the same thing, or if you have a spare moment and could shoot a similar video and post it here, that would be even more awesome. And again, ideally the engine would be warm. Thank you in advance!

---

Here's another video of the actual clunk in action. Again, one wheel is off the ground, brakes are off. Initially I go between some forward gears in sequence and the movement/clunk isn't as strong, but it becomes more pronounced when I go between forward and reverse. Here I lifted the wheel to see how much of the shifting action transmits to the wheels and it seems quite a bit, so maybe the clunk is just an insane amount of lash that was either already in the gearbox and became more pronounced with a different diff in or is coming from the diff itself...

View: https://www.youtube.com/watch?v=L93CkwJJMJ4
 


haste

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#3
Just to clarify. This happened after the quaife LSD was installed? If so, was it by a shop or yourself? Did the shim need to be changed for the preload of the diff bearings? Was the preload checked/adjusted as needed?
 


MagnetiseST

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#4
^ this x1000

Did you measure the run-out of the differential while you were installing it to see if you needed more / less shim? The very first MFactory I installed sounded like this because I had unknowingly removed the shim in the bellhousing side when I replaced the axle seal.
 


OP
foodtruck
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Thread Starter #5
Ok... so I went back to the shop and talked to them. When I asked about preload, the tech's initial phrase was "I set it to zero". Not great, so I tried getting some details... He talked about that it's important to get the float so that the bearings sit there snugly and not too loose and not too tight, but I couldn't get the actual float number out of him. So, overall, it sounds like he set the float... by feel :rolleyes:

I feel super conflicted about it. It seems like reputable shop, reviews are good, and they don't sound like they're trying to brush me aside at all. The tech who did the diff seems like an experienced person and I can believe that he is able to say whether preload is set reasonably right by just feeling it up. You'd think if there was a gross lack of preload, it would've clunked all the time while driving, but it doesn't. However... I'm personally a giant stickler for following the specs and this makes me really uneasy. The shop warranties their work, however I figure I can drive like that for some time before something falls apart (if the float _was_ incorrect). Or, it could be working for a decade without issues other than the clunk, but I don't like the clunk.

At this point, I also don't think there's any point pushing them further, cause if that's how they do things, they're not going to do them differently for me, and if they do, then I don't want the work to be done in a grudge. Current plan is to go to Ford and have them check fluid for shavings / overheating. I will then ask them to drop the transmission and check the end float. Looking at the procedure, it seems that it should be possible to check the float without taking the transmission apart, does that sound right? And then look at what the measurement says and go from there... It's possibly money down the drain but I just don't know what to think at this point.

Incredibly frustrating.
 


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#6
My car has a bone stock transmission but I have observed the 1-2 shift clunk and determined the cause. It's actually very simple, Homer Simpson slapping the head simple.
.
.
.
It is caused by the placement of the foot on the clutch pedal. There is sort a "hole" in the floor of the car and it is critical to get that clutch pedal all the way into that "hole". What has worked for me is to make sure that the ball of my foot is dead center on the foot pad on the clutch pedal. Get sloppy and have the arch of your foot there and you'll get a klunk.

Yeah, I know, it can't be that simple. Been testing this all summer and if i place my foot properly I don't get a klunk. I'll also note that your second video shows the car going forward as you engage the gear and the cause for that is because your clutch is partially engaged. So, just try it out, it won't take even a minute.

PS; I do not know diddly about the Quaife Diff but as I understand it this is a Torsion Differential. This relies on gear angle resistance instead of friction clutches that may explain why you have that much free play with one tire locked.

Just read your report of what the shop who did the work told you. This is the reason why I'll be installing the differential if I ever decide to take that step. Ford has a very specific procedure for installing the differential and IIRC it requires the use of shims and a certified straight edge supported between specific points on the case. It's obvious to me that Ford's procedure was not followed and I would not trust this install as far as I could throw a FiST. Hopefully the dealer will have a technician that will actually follow Ford's procedure for checking this install. As for the cost, if they do find the install wasn't done properly I would be asking the shop who goofed to pay for the correction. If they don't want to do that take them to Court.
 


Last edited:
OP
foodtruck
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Thread Starter #7
Yeah, I know, it can't be that simple.
Yeah, I wish it was. I hear the thump when just moving the selector between second and reverse without even touching the clutch pedal. The synchros are doing their job and teeth are not engaging, so it's not the gear clash... Something pretty heavy is moving back and forth when torque is reversed and according to the tech he just took out the ring gear and left the rest of the shafts in the box as is, so... the suspect is the end play.

From the heft of the thump, it's just hard to believe that one would leave that much slack even if they're setting the preload by feel... Maybe the gearbox heats up and the housing expands more than the differential? Aluminium expansion rate _is_ higher than of steel... :unsure:
 


anticon

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#8
I can't add much to the conversation, but this is definitely one of my main concerns of having a shop install my diff. I have done all the work on my car due to a general distrust of others working on it and cutting corners. At least I know what corners I cut.

Any thoughts on how I can gracefully suggest they review the Ford manual and follow all instructions especially when it comes to setting and checking preload?
 


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#9
Ford's procedure takes the effect of heat into account. It's one reason why the instructions are so specific. Unfortunately my service manual is with my laptop at work so I can only comment on what I remember when I scanned this procedure well over a year ago and my memory is not as good as it once was.
 


OP
foodtruck
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Thread Starter #11
Alright, appointment with Ford is scheduled for Tuesday... meanwhile found a new reliable way to make the transmission clunk.

If I go straight and go on/off the throttle, its normally quiet. However, if I'm in a middle of medium to full lock turn, it chatters every time, both on throttle tip out and back in. Similarly, shifting 1-2 in the middle of a turn results in pretty heavy chatter when 2nd gear synchronizer engages.

Is that something anyone experienced a helical LSD do? Could it be axles going?
 


Last edited:

MagnetiseST

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#12
Alright, appointment with Ford is scheduled for Tuesday... meanwhile found a new reliable way to make the transmission clunk.

If I go straight and go on/off the throttle, its normally quiet. However, if I'm in a middle of medium to full lock turn, it chatters every time, both on throttle tip out and back in. Similarly, shifting 1-2 in the middle of a turn results in pretty heavy chatter when 2nd gear synchronizer engages.

Is that something anyone experienced a helical LSD do? Could it be axles going?
Unlikely the axles, they provide a rotational clunking when going bad.

Chatter might be from your clutch, did you replace it when the transmission was out?

Also what brand / how worn is your rear motor mount?
 


OP
foodtruck
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Thread Starter #13
Clutch/flywheel is about year old, same with motor mounts. I had chattering clutch before, this feels different, like ... gears. And again, its way more chattery when I'm turning, not sure why clutch would cause that. It rattles/chatters both on tip in/out and 1-2 shift when clutch is disengaged.
 


OP
foodtruck
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Thread Starter #14
Alright so... according to Ford, transmission fluid came out totally clean :unsure: Just taking the transmission out is going to be 1k+, so... I guess I'll keep driving it and keep an ear on it if it ever gets worse and check the fluid again in 6mo. Could it be that I just got a unit that has a bit more slop inside? Once they open up the border and I don't have to pay $60 for shipping, going to see if Ravenol is bees knees like everyone says.
 


MagnetiseST

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#15
The fluid can come out fine but you can still have the wrong shims / preload. It should not clunk.
 


MFactory

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#16
Does the clunk only happen when cold? Some play with the worm gears/side gears inside the LSD is normal when cold as we need to account for expansion when heated.Metal expands under heat. If there was no play in the gears when cold, the gears would seize/friction-weld together when heated up
 


OP
foodtruck
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Thread Starter #17
Does the clunk only happen when cold?
Hey, thanks for checking out the thread! Yeah I would totally understand that, but it's actually the opposite, there's more clunks/chatter after I drove for a while, the maybe left the car to sit for a bit, then drove again etc and shifting becomes a bit more notchy in feel.

Going straight, I start getting thump moving lever into second gear and doing so while turning at low speeds results in what feels and what I can only describe as.. small gear chatter and also adds pronounced clunks on tip in/out. Feels like whatever is thumping in unison while going straight is doing so in quick sequence while turning.

Just to add something, Ford techs did the basic diff operation test per manufacturer instructions (turning wheel while holding another one etc) and it all checked out fine.
 




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