Looking at a 1996 F-450 Diesel / Auto. I have heard rumors that the transmissions in these trucks don't take well to the power of the engine. I used to drive a '95 cube van with this configuration with no problems. Is there anything to be concerned about? is the problem with the 5 speeds as well (or only)? I would appreciate any insight available. Thanks
There are not design flaws that I am aware off. It is more a usage issue. If it is lugged down a lot into stall range in gear it will generate a lot of heat with is very hard on tranny. If you keep RPM up above 2000 RPM or so while pulling hard, you should have no issues, Also when you chip or boost engine, that boost the strain on tranny and can lead to a early failure.
Lugging into stall range makes me think manual trans... are the auto transmissions less prone to this sort of failure since they tend to prevent this? I know heat is also the bain of the auto, but lugging is much less likely. thanks
Matt
Your converter in your truck stalls between 1600 and 1800 RPM but does not acheive flud coupling until about 2000 RPM or so so when you are pulling hard and RPM is below 2000 RPM, you will be making some extra heat if converter clutch is not locked up. Excess heat is the number one cause of tranny failure with automatics. You might install a tanny temp gage and when temps get up to and above above 220 or so, throttle back and let it cool some. The ideal range is about 180 to 200. Some let them go higher still in temp before shut down but even if you use SYN fluid that can take the heat better, the seals in tranny cannot and frequent temps much above 220 or so can shorten their life a bit and above 240 it can shorten it even more. Much above 240 is slow death with above 260 to 270 usually causing damage that may surface quickly or a short time later At around 280 to 300 it can be trashed very quickly.
Its all about the heat, and if you install a temp guage and an aftermarket cooler then all should be well. The other thing you can do is when the temp starts goin up, just put it in neutral and rev the engine for about 30-45 sec. this will get the hot fluid out of the t/c and send it off to the cooler so it can come back nice and cool. I have seen transmissions shelled really fast because of improper cooling. It aint pretty and its even more embarrassing to see your ass sittin on the side of the road cause you didnt take some small precautions. This does NOT effect standard transmissions, only automatics. The heat breaks down the fluid and "burns" it. When this happens the friction plates in the clutches start to eat off their friction lining, and then its all gone.. NO more.. LOL SO thats the long and the short of it.
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