CPT
05-15-2013, 04:44 PM
I get asked quite often why we don't use 5 pinion 4L65E planetaries. Actually there are a few reasons that I will try to explain. The largest percentage of the time that a planetary fails is because the needle bearing set under the sun gear fails first. When that bearing fails, it sheds needles through the pinions, causing it to self destruct. Both 4 and 5 pinion planets use the same style bearing. I've never seen a 4 pinion planetary fail in a way that a 5 pinion wouldn't have failed the same way. Now, we add in the other factor. 5 pinion planetaries are much heavier than 4 pinions. This is rotationg weight. The more weight you have to spin, the more horsepower it takes to turn something. It may not be dramatic, but a few extra horsepower is a few extra horsepower. The other thing in cost. A REAL GM 5 pinion rear planetary costs upwards of $400. Many shops will advertise "5 pinion planetaries". The first question should always be, "Are they REAL GM planetaries". There are companies making cheap knock offs that I've seen fail is as little as 300 miles. I've seen the pinion exles fall out, and the housings themselves shatter.
So, in a nutshell, a 5 pinion offers little, if any strength improvement, they cost a couple horsepower, they're heavier, and unless they're REAL GM planetaries, they're actually weaker. CPT does however offer 5 pinion REAL GM planetaries as an option if the customer is dead set on them.
Frank
So, in a nutshell, a 5 pinion offers little, if any strength improvement, they cost a couple horsepower, they're heavier, and unless they're REAL GM planetaries, they're actually weaker. CPT does however offer 5 pinion REAL GM planetaries as an option if the customer is dead set on them.
Frank