Posted by Greggg [50.158.210.156] on Thursday, December 05, 2013 at 02:50:27 :
In Reply to: Re: How many splines on the output 23? posted by Kaegi [98.247.164.246] on Thursday, December 05, 2013 at 00:34:37 :
Stock bigblock engines have plenty of torque to grenade a 205 when you have good traction, nothing exotic. There are lots of outrageous power levels being made by modern diesel pickups, the vast majority of which are running chain cases and holding up. I'm not saying chain cases are the best thing out there for every application. But they have been the only game in town as far as the big three OEM cases, for over 20 years and they are holding up well. You said to look at used trucks older than 10 years old many with bad cases, all chain drive. Well when the chain design is the only case being offered for about the last 22 years of course you will find all the bad ones being chain cases. Thats the law of averages, not indicative of a bad design.
I am not denying a chain can stretch and wear into the case causing a leak and subsequent bearing dmage. But is that not neglect on the owner? The same for a leaking seal on a gear drive that runs dry and ruins the bearings. I do run an aftermarket gear drive case on my Jeep with a Cummins engine and it does great and has a very good low ratio. But before that I beat the tar out of a NP231J with a small 1" chain and only a 3 pinion planetary it did great as well with no issues. I was very surprised at how well it did considering the beating it saw. I went to an Atlas to get a better low ratio and more speeds because when you have a limited rpm range like a diesel does you need gears to get the wheel speed you need.
By design a gear case will be spread apart by the gears when over stressed. A chain case will pull together in the same situation which is why chain t-cases don't need the beef of a cast iron case to get its strength from. The 205 is based off of a 70 year old design. It was good in its day, in fact it was a great transfer case in its day. But that day has passed due to advancements in powertrain design. The old np208 had some big shoes to fill when it replaced the 205, but modern day chain cases are much improved versions. Just like the 205 was a much improved version of its predecessor the 200.
Follow Ups: