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Posted: 3/19/2008 12:13:54 PM EDT
| I just ordered an (another) XM16E1B lower from Nodak (one of the anodizing imperfection Blem Lowers) and already have a Forward assist upper, so thought I'd try and mimic the GM Hydromatic Division Anodizing color with Norrells. A buddy has a very busy auto repair garage, so I imagine I'd be able to look at an old automatic tranny for comparison, but does snyone have a picture of one of these Hydromatic (or is it HydrAmatic) M16 Lowers to compare colors to? |
| While I have no idea what GM trannies look like or even if they are anodized, I have seen a refinished hydromatic reweld. It turned jet black when it was reanodized. The anodize job brought out the welds a bit but it was still a stellar example of someone rebuilding a rare lower. I would say if your trying to mimic a GM lower and are asking what color were they I have to answer I don't know. I can say that if you want your upper and lower to match that Norrels is the way to go. Other than that you can try getting an upper and lower done at the same time by an anodizer and see how it turns out. Different alloys and heat treatments will effect your color some or so I have heard. |
| Unless GM hydramatic transmission housings were made of aluminum, the housing color isn't going to tell you anything about what color anodizing they used. In fact, even if it was aluminum there isn't any reason to think the receivrs and ttransmission housings were anodized in the same batch/place. |
My understanding was they were made of aluminum, and they anodized in the same manner as the tranny cases. Course, I could be misinformed, hence my asking. |
| GM Hydramatic tranny cases WERE made of aluminum, but they were NOT anodized.That is a myth.I have had several of them in my garage and under all that dirt and road grime, they are just plain aluminum.My brother was issued a Hydramatic M16A1 during the Desert Storm years,and he says it was a little darker than the Nodak retro receivers.The only thing the transmissions and the M16A1 rifles had in common was the name of the General Motors Division who built them. |
For the most part, automotive transmissions have had cast aluminum cases since the early 1960's. An automotive transmission made of cast iron is UNGODLY heavy. I've only come across one in all my years of automotive-scrounging; that was a cast iron Powerglide in a '67 Checker Cab. That whole car was built just like its tranny; very old-school even for its time and it must've weighed 8,000 lbs!! As was mentioned, GM didn't anodize their transmission cases; that would would adversely affect the precision tolerances required inside of automatic transmissions. |
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