gm 5 pinion planetarys
Thread Starter
Staging Lane
Joined: Nov 2011
Posts: 55
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From: Hamilton, Ontario
gm 5 pinion planetarys hey guys i have been looking high and low but can not find any part numbers for the factory gm 5 pinion planetarys. i can find aftermarket ones but i think there is no point switching to the after market ones. do any of you guys know the number for the factory gm ones
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
I don't know the GM part numbers, but I bought both the front and back one for about $160 each from this ebay seller:
http://stores.ebay.com/trutechperformancetransmission
Note: the front one requires a new-style reaction carrier which he sells as a kit.
They were brand new in AC/Delco boxes and I have every reason to believe they are genuine. Also the seller spoke to me on the phone for 20 minutes and was very knowledgeable. I was very happy with everything I bought from them.
Several trans experts have told me to avoid the aftermarket 5-pinion units like the plague; they are poorly make in China and are weaker than the GM 4-pinion units.
http://stores.ebay.com/trutechperformancetransmission
Note: the front one requires a new-style reaction carrier which he sells as a kit.
They were brand new in AC/Delco boxes and I have every reason to believe they are genuine. Also the seller spoke to me on the phone for 20 minutes and was very knowledgeable. I was very happy with everything I bought from them.
Several trans experts have told me to avoid the aftermarket 5-pinion units like the plague; they are poorly make in China and are weaker than the GM 4-pinion units.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
I haven't heard of high rpm problems with the 5-pinion planetaries.
Only thing I have heard from several builders is that when the rear 4-pinion planetary fails, it is not because the gears break (at least initially), but because the stock design of the sun shell and sun gear places too much lateral force on the small internal torington bearing, which then dramatically overheats, turning the metal blue and causing the unit to fail. As I understand it, some buildesr try to bring more oil there for cooling. The Sonnax smart shell is designed to solve it. (I measured and confirmed that the sun gear is then completely unloaded.)
I carefully compared my 5-pinion planetaries with known GM units (from 4L65E) to confirm that I bought genuine GM parts.
Only thing I have heard from several builders is that when the rear 4-pinion planetary fails, it is not because the gears break (at least initially), but because the stock design of the sun shell and sun gear places too much lateral force on the small internal torington bearing, which then dramatically overheats, turning the metal blue and causing the unit to fail. As I understand it, some buildesr try to bring more oil there for cooling. The Sonnax smart shell is designed to solve it. (I measured and confirmed that the sun gear is then completely unloaded.)
I carefully compared my 5-pinion planetaries with known GM units (from 4L65E) to confirm that I bought genuine GM parts.
