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H&S HD300 transmisson issues?

2K views 2 replies 3 participants last post by  drewactual 
#1 ·
Im getting ready to install a H&S mini max on my 08 F350 with 5inch dpf delete and a s&b intake. Just looking to see if anyone has had any transmission slipage or failers on this tune. I do a few truck pulls every now and again, maybe 3 or 4 a year.
 
#2 ·
I have been running it for a long time and have raced it several times and mine still seems to be doing ok. Sometimes it does some weird stuff and I wish the shifts were a little more firm but so far so good. I have not pulled a sled with it however.
 
#3 ·
Stolen from another thread:

I don't think the H&S transmission tuning is the cause of transmission failures..

they are basically intended to take the slop out of the OE tuning.. that slop hides a lot of issues, and coupled with torque management, can keep a transmission from 'showing' any problems, though the problem exist all the same..

any time you tune either an engine or drivetrain, what you gain is what the factory put in place for safety margin, most often.. It's not like you're introducing a new function with the transmission tuning, it's just that you are telling it, more specifically, what you want out of it..

these trans weren't designed for the torque a tuned engine can lay to it- but they can handle it, so long as the slop in between gears is reduced.. this is why the shift is firmer- it reduces time in between just like a shift kit valve body used to do to older designed automatic transmissions..

time in between gears produces hella heat, and heat eats transmissions like no other factor... energy has to go somewhere, and it is manifest in heat during the transition between gears, or before power leaves one clutch and moves to another.. easier said, while torque (spinning power) is being misused due to transition between gears, it expels it's energy in terms of heat..

any time the torque converter is unlocked, the engine is spinning the input shaft faster than the transmission is reacting.. this is where torque amplification takes place, and is a needed factor on engines that produce less torque than what is being demanded.. once that t/c locks, there is a mechanical connection made between the t/c and the transmission, and the input shaft is matching RPM's with the engine.. it GREATLY reduces the loss of energy (heat), but it puts all of the strain on the engine... you want that t/c unlocked to provide leverage to get things going.. as is its design.. you want it to lock up, though, if you're not demanding a lot (you're unloaded) as soon as you can-because you reduce heat.. heat murders transmissions..

H&S is levering formoco design with their tuning.. they allow the transmissions to be manipulated to better suit the purpose you decide is your own.. you can avoid t/c lock until later- which allows for better performance because the t/c is using hydraulic coupling to amplify RPMs and moving you with more torque (literally spinning power, but think of it as 'harder to stop' than horse power- otherwise known as the rating used to determine how much work and how quickly can be accomplished).. avoiding t/c until later is good for a truck that actually works a lot; as in towing or hauling.. it is also good on the track if your intent is racing around.. It's bad for transmission longevity, though...

for the transmission to live a long and healthy life- reduce the heat, pretty much plain and simple.. remove debris as a secondary concern.. but the heat can be reduced by using the tuning that allows t/c lock as soon as your needs determine is possible. It can also be manipulated by choosing what gear and when.. if you can get to fourth and hold steady without straining the engine @ 35mph, by all means do it... if you pull a lot, and don't wanna let go of fourth until 45mph because that is what you need, by all means- do that.. if you're into getting a few tenths of a second off your 1/4 time, use the late shift schedule and turn your o/d off.. if you want that trans to live long and prosper, though, and you don't need it, shift and lock up as early as you can...

if you want to find an issue either present or developing, put it in as late a shift and lock as you can, and drive it a little harder than normal.. that is all H&S tuning is going to do to your trans, is it is going to point out issues that already exist..
 
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