# Chevy Bolt differential



## Yodastien (Oct 25, 2020)

Does any body know if the Bolt Differential is shared with any other GM platform, I was wondering if there was the possibility if it was shared with something like the sonic to lend possibility for a limited slip unit.


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## rmay635703 (Oct 23, 2008)

The Bolt is a Trax, you would need to scope out the mounts and other goodies to see if it roughly fits anything else.

ive never seen a tear down of the transaxle , spline and other components would need to be identified


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## Yodastien (Oct 25, 2020)

This is a great tear down video


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## brian_ (Feb 7, 2017)

rmay635703 said:


> The Bolt is a Trax, you would need to scope out the mounts and other goodies to see if it roughly fits anything else.
> 
> ive never seen a tear down of the transaxle , spline and other components would need to be identified


A Trax, or Sonic, or Spark, or any of the GM Gamma II platform vehicles could share this component. On the other hand there are so many differences between the Bolt's transaxle and the transaxles used in the other vehicles on this platform (at least two different manuals and at least two different automatics) that it isn't at all certain that the differentials are shared. Because the Bolt is more powerful than any engine in any Sonic or Trax, it's possible that the differential is from a differents parts bin, shared with a larger model.

Bearing diameters and spacing, output splines, ring gear bolt circle diameter... there are a bunch of critical dimensions if comparing potential differentials. A complication is that one output of the Bolt diff is inside the hollow motor shaft, which changes the bearing configuration on that side - you can see the very large diameter bearing on that side at about 24 minutes into the video.

The GM 6T40 seems like the most likely transmission to share components with the Bolt, since it is used in Gamma II vehicles and is also used in much heavier cars so it should be able to handle the Bolt; the 6T35 is also a possibility, and may use the same differentials. The Ford 6F35 is apparently the same design; the diff might be interchangeable but that's far from certain.


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## lj516 (Mar 11, 2020)

There are a few companies that make lsd's for any diff, they can tell you if dimensions are shared with any other part.


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## diggerdave (Dec 25, 2020)

Yodastien said:


> Does any body know if the Bolt Differential is shared with any other GM platform, I was wondering if there was the possibility if it was shared with something like the sonic to lend possibility for a limited slip unit.


In this video Kelley has the drive unit all laid out and explains that it is a one speed trans. As such no gas car is going to share this drive.


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## brian_ (Feb 7, 2017)

diggerdave said:


> In this video Kelley has the drive unit all laid out and explains that it is a one speed trans. As such no gas car is going to share this drive.


That wasn't clear to you from post #4?

The whole transaxle is not shared with any other model, but the differential could be; however, as I mentioned, due to the bearing configuration resulting from the coaxial design, it likely that it's not shared with anything.


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## Yabert (Feb 7, 2010)

Yodastien said:


> ..... possibility for a limited slip unit.


I'm also really interested to put a LSD inside my Bolt (Vanabolt). Live with a 1x4 vehicle (as most vehicles) is sush a pain during snowy winter.

I don't know how to find a Torsen LSD for my Bolt, but there is all the dimensions of a Chevrolet bolt differential below.

If someone can suggest a way to find a compatible LSD based on the dimensions, please let us know.
Thanks


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## remy_martian (Feb 4, 2019)

Sounds easier to play with the ABS...what inverter/VCU you using?


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## brian_ (Feb 7, 2017)

Yabert said:


> I don't know how to find a Torsen LSD for my Bolt, but there is all the dimensions of a Chevrolet bolt differential below.
> 
> If someone can suggest a way to find a compatible LSD based on the dimensions, please let us know.
> Thanks
> ...


It's not easy to add the bulk of a typical limited-slip differential to a housing not designed for it, and unlike common axles and final drives for which the options are well-known, EV drive units are relatively obscure.

The good news is that some work has been done on this. The Torsen and similar gear-type diffs are compact, and Zero EV has arranged for Quaife ATB units for some of the Tesla drive units... perhaps just because both companies are in the UK, but Quaife is well-known worldwide The ATB is the same design as the Torsen T-2 or Type B.

The best part might be that Quaife seems to be relatively open to new applications and to individual queries. The drawing probably has everything they need to find a fit (from a matching vehicle) or determine that they don't have one. A call to Quaife (yes, actual telephone conversation) is probably worthwhile.

I note from the drawing that the output bearing journals appear to be the same diameter - the unusual coaxial shafts on the motor side in the Bolt transaxle change the bearing details but apparently not the inside diameter that matters to the diff. That's promising.


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## brian_ (Feb 7, 2017)

Yabert said:


> Live with a 1x4 vehicle (as most vehicles) is sush a pain during snowy winter.


First, a minor note: a one-wheel-drive four-wheeled vehicle would be a "4x1", not a "1x4"... it's always _wheels X driven wheels_.

More importantly, there's a huge difference between being limited to the traction of the lowest-traction driven tire (the situation with an open diff) and an actual one-wheel-drive vehicle. Until one tire slips, all the driven tires are working, delivering far more drive than just driving one tire.

Most vehicles, especially front wheel drive and electric vehicles, have open diffs. Open diffs might be even more common than in the past, because everything has brake-based stability control now, and it works well for traction control in normal use (even if not for racing or off-road use due to brake overheating in sustained operation) so there is little incentive for a manufacturer to go to the expense of an LSD in these vehicles.

A problem for conversions - and what Yabert is experiencing - is that if they use a salvaged EV drive unit they don't have a mechanical limited-slip differential, and usually they lose the electronic systems including brake-based traction control.


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