Downshifting an automatic?????
08-18-2006, 08:06 PM
#1
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Downshifting an automatic?????
Hi, I have an 01 1500HD with the 6.0 / 4L80-E.
I am a landscape contractor and I normally haul up to 2 tonns in the bed. I know this is overloaded but ... but... meh it does the job.
My question is- Does downshifting an automatic to slow down the vehicle and save on the brake while hauling heavy payloads hard on the tranny? Will it lead to premature transmision wear? My auto teacher used to tell me absolutly not but my dad says it is hard on the tranny and a few other people have told me the same. I just hate replacing brakes.
I am a landscape contractor and I normally haul up to 2 tonns in the bed. I know this is overloaded but ... but... meh it does the job.
My question is- Does downshifting an automatic to slow down the vehicle and save on the brake while hauling heavy payloads hard on the tranny? Will it lead to premature transmision wear? My auto teacher used to tell me absolutly not but my dad says it is hard on the tranny and a few other people have told me the same. I just hate replacing brakes.
08-18-2006, 09:02 PM
#2
It's hard on the clutches in the tranny to slow that thing down, especially fully loaded. When you select a lower gear the tranny drags the engine RPM up, and all the time between when the revs start to increase to when they stop is time that the clutches are slipping. I used to downshift my 4L60E cause I like how the exhaust sounded, then it burnt the 2-4 band. Use the brakes IMO.
08-18-2006, 09:25 PM
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Originally Posted by TIM Z
Also Dont do headers with your future Turbo install, they dont hold the heat like the stock manifolds do and turbos like heat.
Good to know. Thanks
I guess I will stop using the trans. I dont do it often so i don't think theres any damage done.
08-18-2006, 09:40 PM
#7
I would not use a 4L60-E to decellerate by downshifting, but the 4L80-E is designed for it. You have a 4L80-E. The overrun clutches in the 4L80-E are HUGE compare to those in the 60. The overrun clutches are only used for engine braking. Even a 4L80-E pulled apart with 250k miles on it show practically no wear on those clutches.
Also, the 4L80-E has a gear pump designed to provide higher sustained line pressures than the shitty vane pump in the 60-E. The robust hydraulics allow higher line pressures to be calibrated into the PCM at zero-throttle. In fact, the factory programming commands enough line pressure to hold everything under even severe engine braking in the 4L80-E. The engine would redline far before the trans slips in a downshift.
Have fun.
Also, the 4L80-E has a gear pump designed to provide higher sustained line pressures than the shitty vane pump in the 60-E. The robust hydraulics allow higher line pressures to be calibrated into the PCM at zero-throttle. In fact, the factory programming commands enough line pressure to hold everything under even severe engine braking in the 4L80-E. The engine would redline far before the trans slips in a downshift.
Have fun.
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08-19-2006, 08:43 AM
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Originally Posted by James B.
I would not use a 4L60-E to decellerate by downshifting, but the 4L80-E is designed for it. You have a 4L80-E. The overrun clutches in the 4L80-E are HUGE compare to those in the 60. The overrun clutches are only used for engine braking. Even a 4L80-E pulled apart with 250k miles on it show practically no wear on those clutches.
Also, the 4L80-E has a gear pump designed to provide higher sustained line pressures than the shitty vane pump in the 60-E. The robust hydraulics allow higher line pressures to be calibrated into the PCM at zero-throttle. In fact, the factory programming commands enough line pressure to hold everything under even severe engine braking in the 4L80-E. The engine would redline far before the trans slips in a downshift.
Have fun.
Also, the 4L80-E has a gear pump designed to provide higher sustained line pressures than the shitty vane pump in the 60-E. The robust hydraulics allow higher line pressures to be calibrated into the PCM at zero-throttle. In fact, the factory programming commands enough line pressure to hold everything under even severe engine braking in the 4L80-E. The engine would redline far before the trans slips in a downshift.
Have fun.
So your saying i dont have to worry about anything when i downshift and that the 80-E is actually designed to be downshifted.. sounds ok becuase this is the heavyduty tranny they put in all the 2500's.
Anyone else want to agree to James B. just so i feel 100% safe.
08-19-2006, 09:46 AM
#9
IF thats the case, then having a fully built 80e like mine should totaly be up to the challenge! The only thing my turck hauls is ***! LoL I plan on installing a Rachet shifter in my custom center console so i can command the trans to down shift for braking and to prepare for owning a ricer or two... LoL
