Update: March 13, 2024
I received the first batch of nine Quaife ATB's, and have fitted one to my 2017 F-Type V6 Manual (3.31:1 ratio)
The removal of the OEM rear diff, and the installation of the rebuilt ATB diff into the F-Type was done in my garage with common tools and jacks.
The rear sub-frame (independent rear suspension) was lowered to access the differential retention bolts, and this process wasn't too bad.
See YT video listed here fore more details on this process.

The next step is to start updating diff units for the first group of Forum members.

To answer some common questions :

1. Yes, this upgrade should fit many recent Jaguar models (XF, XE, F-Pace and F-Type) with similar independent rear suspension and differential
2. So far I have identified a few gear ratios with known spacer rings: 3.15 , 3.23, 3.31 (other ratios may need a different spacer rings, and I can help determine these)
3. Yes, I am developing a kit of parts and special tools with detailed instructions to help enthusiasts rebuild their own rear diff with good results. (some shop and automotive mechanic skills are required)

Drive well,
Herman


Quaife ATB's for first group of Forum enthusiasts

 

Update: March 16, 2024
It is a few days later, but I just wanted to get this quick update out there, before I take my car on a 500 mile business trip.

With the car still on jack stands, I thought a bit of spinning the rear axle would help distribute the freshly filled differential oil.
But this resulted in all sorts of nasty friction noises from the back of the car.... full stop.
It turned out to be the rear brake rotors being clumsy without the wheels bolted onto the hubs.

So I mounted the wheels and put the car on the ground and reset the EPB.
Backing out of the garage resulted in a nice big "clunk" from back of the car... full stop #2.
This turned out to be the emergency brake releasing.

These false alarms put me on bit on edge, so I carefully drove over to a parking lot where I could do some slow figure 8's.
No noises, no tires fighting each other, just simple, smooth operation from the rear differential. Good.
Next was moderate torque acceleration. No issues.
Finally, was a high torque acceleration on a highway on-ramp.
Very nice, the rear end "hooked up" with the pavement to send the F-Type forward with authority.

The next step for me is to assess the new rear differential on my week-long business trip.
Hopefully I will see some wet cold conditions where the original open differential had issues with finding grip.
Then I will rebuild units for the first group. @unhingd @Lizzardo @JMO @spinningcog @naif Kasherqri @Blue-F @JoeyTheAsian

Drive well,
Herman

 

My trip up to Vermont went well with the new Quaife helical ATB differential.
Yes it works as advertised, and a quick inspection shows no oil leaks and cool operation.
My only complaint is that some gear meshing noise is perceptible at low speeds when turning and accelerating out onto major cross roads.
Otherwise the ATB unit offered great grip (especially relative to the stock open differential), and the rear end was well behaved even in the winter conditions.
There were no issues coordinating with the F-Type’s Dynamic Stability Control (DSC).

Now on to building units for the forum members.

Test Drive in Vermont of Quaife equipped F-Type

 

Status Update: April 18, 2024

I have worked with the original gang of helical ATB enthusiasts here on Jaguar Forums and have built up their rear differentials.
Many are now being installed as we speak and I can let them report back on how they like their new found grip.

After the dust settled, I have 3 Quaife units availale to interested folks.

You can drop me a PM or e-mail me at OncaEngineering@gmail.com

Herman

 

I still need to send my spare across the country for the ATB treatment but have been a bit overloaded. Even when I have it back I'm not sure when I'll get it swapped. It's certainly an albatross in the garage right now. A 75lb. albatross.

 

@lizzardo
I have a second option... If you are up to it, I could send you a kit of parts, tools and directions.
This would save you from shipping your donor unit to me. You would be the Guiney pig for this DIY process.

 

I was planning on having you do it but this is tempting. Not only do I skip the trouble of shipping but the expense. Now that you've set up several of these I expect your instructions should be fairly well developed. I'll pick up this conversation in private messaging.

 

I spent Sunday with 2 friends, 1 lift, the Onca Engineering diff kit, and 4 hours.

Out with the OEM open diff (3.31) in with the Quaife unit (3.15).
5% less RPMs to equivalent speeds is not much of a difference but it’s enough to make the drive train unique, a little more room in 3rd & 4th for the back roads.

All going well. I will let you know if I hear a clunk, a ghost old school bus or my 64 s type with the non-synchro Moss box approaching from the rear.

Last month I replaced the blown coolant pipes.

Next month Fly wheel & clutch, I got to get rid of dealing with lethargic shifting and managing flywheel momentum.








Jim
Maryland
2016 f type
Basic, 6 speed

 

Hi Herman,

I just swapped my open 3.15 for a V6S 3.31 dif (amazing difference by the way, I was nervous about the ratio change and now i'm glad of it), just wanted to say that we saved a lot of work by instead of lowering the subframe, we made two small flat grinds for a open wrench (to hold the main bolt from under the nut), has no mechanical downside because the modifyed section is under the nut.

Thanks for tall this public work you're doing, it's amazing. I was wondering if I would ever find if the LSD was 1 way or 2 way and you made it very clear by disassembling it. Chapeau!!! And thanks for the porsche rebuilding tip!

I really hope your project goes well, you really deserve it after all this work!!!

Diogo

 

Diogo,
Thanks for your update.
(I am starting a new Forum account called "Onca Engineering" )
I am glad you were able to change out your (Automatic base model) 3.15 ratio for the V6 S model 3.31. This will only lower your car's gearing by 5% (make it a bit more sporty).
The ZF 8-speed automatic has so much range (from a low first gear, to a tall 8th gear), that a slight adjustment of the differential ratio doesn't present much risk.

Can you send a picture of the lower end of the front differential mounting bolts?
How much of a flat grind was necessary?
How much torque was required to overcome the nyloc on the 18mm nut?

This trick will make the differential swap much faster!

 

Hi Herman, I went trough your videos before the "operation", I did it with my friend and his main goal was to be able to do it without lowering the subframe, he was really commited to this, for the left hand drive side he modified a open wrench (bended it into a rainbow shape) and this alone allowed him to reach the bolt from the top, but then, this wasn´t enough to reach the right hand side bolt head so he came up with this ideia, and I agreed with it imediattly. So I suggest that this can be done by the grinding method on both sides!

Its super trick to take the picture without a lift but I think this is good enough to show what I meant (didn´t come to my mind at the time to make a picture!!).


About the torque needed, my friend was unbolting it so I can´t really tell, but it was "normal easy" looking from outside, no trouble.

I hope this helps the process to be faster for you guys! Thank a lot for your help.

Diogo

 

Please update us when you do.
Would be curious to hear about your results as compared to the current "lethargic shifting and managing flywheel momentum".
I can definitely relate to having to manage flywheel momentum 😩.
​​​​​

 

This is a fantastic resource! I'm a junior member here having just picked up a 2015 F Type S with 35K miles. I really like the car. Recently I've had some "rubbing" noise from the rear of the car and my mechanic diagnosed it as rear differential issue. They changed the fluid and it came out looking horrible, very dark, with suspended metallic and clutch friction material. Now I'm looking for a replacement rear diff. I really like the idea of the Quaife ATB. I've sent an email to Onca Engineering this morning regarding one of their replacement units.

 

Hi folks,

I've had my Quaife LSD from Herman/Onca Engineering for a couple of months now, and I have to say it's made a major improvement to the amount of traction available. It's of course most noticible in low traction situations (Merging onto a busy street in wet conditions), but is noticeable more often than you might think. Working with herman was great, and I would whole heartily recommend this upgrade.

 

Likewise. I'm loving the quaife atb in my car. The base trim without an LSD is missing much of the 'soul' of a sports car during spirited driving. For the price, its an absolute must have. The peace of mind of knowing it will work as designed indefinitely without much upkeep is also a huge plus compared to the factory lsd clutch packs on the v6s models.

 

My parking brake also gives a little clunk sometimes. Not sure if this only happens when I forget to release it before putting it in drive or the opposite. Anyone else?

 

@dbritt320
I don’t normally activate or release my V6 Manual’s parking brake. It sort of does its own thing and applies itself when coming to a stop, and releasing itself when I start to pull away. Sometimes I can feel it release if I pull away very slowly. Overall I am very satisfied with the implementation of the EPB in the F-Type. Is if different on the ZF 8sp Auto?

 

AFAICT the EPB with the auto box automatically applies itself on all but the earliest model F-Types.
Mine is a MY 2015 and the EPB does not and never has auto applied itself, I think the change came in with MY 2018 maybe MY 2019.
However my EPB does auto release most of the time but sometimes it does not, I think it's down to when/how the EPB was applied (eg whether in N or D) but I've never tested this to see how it really works.

 

I always manually apply the EPB when I park, but I've only manually released it once, to see that it works. It's always released without any fuss on light throttle application.

 

I've recently had the Quaife ATB installed into my 2015 F Type S (~36,000 miles). I purchased the car about five months ago, and a couple of months into my ownership the rear diff starting making "rubbing" noises. Having spent quite a bit of time researching F Types before purchasing, I knew right away it was the LSD unit. I contacted Herman at Onca Engineering and he worked with Quaife to get me their ATB unit, along with his installation kit. My local shop had the rear diff R&I completed in just over a day, with no issues reported.

Driving impressions: I've not had the opportunity to do a long road trip yet, but on my daily local loop that includes a long roundabout, the Quaife ATB completely changes the way the car handles power-on tight turns. With the OEM LSD, the RWD car was twitchy under power going around the turn, with the traction control engaging to keep the rear end from swapping places with the front end. Using the same technique to navigate the turn, the Quaife ATB torque biases to the wheel with more traction, in this case the outboard to the turn rear wheel. I could feel the right rear tire "dig-in" to the turn and provide a planted feeling in the turn. Amazing!

If you're on the fence as to whether to rebuild your LSD or purchase the Quaife, you really want the Quaife ATB. I have the OEM LSD on my workbench now, and the clutch pack has half the disks with almost all of the clutch material gone, down to shiny metal.

Herman has been great during the whole process. Once we determined the path ahead for my car, he contacted Quaife and obtained the ATB, which Quaife shipped to my address. Herman then put together the assembly package, which included all consumable parts and "special tools" that make the job more convenient and sent those to my address as well. Also included are detailed instructions and a video. Herman is also on-call to answer any questions, and, is a great guy to talk to. Thanks Herman!

I'm just going to close with, you know you want the Quaife ATB, just do it!