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Why is the G Body rear end called Metric? Are all G body Metric rear ends considered 7.5” ring gear? Where can I research about this?
 

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not sure about the "metric" name but not all Gbodies have 7.5" rears, some do have 8.5" but very few of those
 

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Can't say I've heard them term for G-body rear ends. If I had to guess I'd say that it may be because G-bodies have a mix of metric and imperial parts in it depending on when the part was designed as GM slowly converted over to using the metric system.
 

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My 86 ECSS has METRIC stamped in the tranny pan , It's a TH200c I believe , I think that means that some or all of the parts use metric measurements instead of SAE but I'm just guessing .
 

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this link

the general thought seems to be that it refers to the fasteners, but even then apparently there are exceptions....
 

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My Th200 has a metric pan also. I don't what that means. It's my spare transmission now,as I put in a 2004r, and that's what I'm using.
 

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it's mostly the chassis called metric not the rear end
issue is going to be metric (82-88 G-Body) vs. imperial (78-81A-Body) fasteners. From 78-81 there was a slow and confusing conversion to metric fasteners.
 

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I was always told that G body is a metric car since they used metric lug nuts starting in the early 80s.
 

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The changeover was slow because GM wasn’t going to revisit old engineering and change it to metric, but anything engineered after some date around 1978 would be metric. So, the small block engine and all its fasteners were left alone. New stuff like the sheetmetal, smog pump brackets, the 200C trans, etc. were metric. (I’ve never heard the rears called metric, though).
GM did similar things with other ‘new’ ideas; I had a ‘78 DeVille that had modern blade fuses while my ‘79 Trans Am still used glass.
Patrick
 

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I did not like it when the US started with this metric crap, but It is obviously here to stay. I guess we have gotten used to it by now. I know the reason was to have a standard around the world. So we switched to using the same standard that other countries use. Why did we have to be the ones to change? No doubt that the manufacturers did it for monetary reasons. Sorry about the rant. It is definitely an old school feeling.
 

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I did not like it when the US started with this metric crap, but It is obviously here to stay. I guess we have gotten used to it by now. I know the reason was to have a standard around the world. So we switched to using the same standard that other countries use. Why did we have to be the ones to change? No doubt that the manufacturers did it for monetary reasons. Sorry about the rant. It is definitely an old school feeling.
I mean as an engineer who deals in both I would say that Metric is a much better unit of measurement than Imperial. Conversions all make more sense being that they're all based on units of 10 instead of the imperial standard's logic of "well a king 600 years ago decided this makes sense so let's keep doing it". Also the US is the only 1st world country still using standard which is why we needed to change. The change was absolutely done for monetary reasons. GM like pretty much every other automobile manufacturer is an international company and it doesn't make sense to make a specific set of tooling for one country. Plus it would just add an additional opportunity for mixups to happen on the production line which isn't good for anyone.
 
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