bastarddsm
20+ Year Contributor
- 5,643
- 1,478
- Aug 26, 2003
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Mendota,
Illinois
That's not going to do anything but cost people money.Someone get FLF on billet bell housings and mid sections
2 big failure points for AWD, FWD is the same only 4th gear drives it.
1. Intermediate shaft and CD Gear: This gear takes roughly 3 times the tooth bending stress as first, and 2 times as second, and it has a very similar tooth profile. This gear pair should have the same profile and width as the output ring an pinion.
This problem is exacerbated by 2 other design flaws.
2. 4th gear is way too narrow. If you look at any manual trans design papers it they suggest designing first and second to like 80% of yield strenth for your projected torque input, and like 50% for 3rd and 4th. Reason being your not in first and second long enoug to accumulate many load cycles. You spend most of the time in higher gears to they will fatigue more. If you reduce the stress it takes longer to fatigue them.a. The intermediate shaft is an idler, which means the teeth are reverse loaded. This kills the endurance strength by 75% or more.
b. 3rd gear is narrower than the intermeadiate shaft. This is a stress concentration and also hurts the life of the intermediate shaft.
b. 3rd gear is narrower than the intermeadiate shaft. This is a stress concentration and also hurts the life of the intermediate shaft.
I'm sure there are some defficiencies in the case, with our tooth profile and pressure angle you are well into low cycle fatigue failure before you yield the cases.
Seperating the output from 3rd gear would make the biggest difference in the longetivity of a dsm trans.
An example if this. Look at the evo trans, thinner gears but they last much much longer before they strip them. Output is taken from the shaft, not 3rd gear.
Second example 3/s transmissions, the 3rd, I shaft, and CD has a much bigger profile and wider tooth. They don't break.
The play for FLF would be a bellhousing that puts 3s trans guts in a dsm. That would be the tits. $2000 I would buy that.