OK to Downshift?

[tlong]

Does a manual downshift hurt the '96 auto trans? The revs are never outrageous, but will an OD to D, D to 2nd wear it out prematurely?

I like to go in D under 50. Great speed control. The car never downshifts out of OD unless I ask it too with gas, great torque at 1000 to 1500 on the uphill. But I shift down on the fly occasionally. Asking for trouble? I need intervention.

 

[c4cruiser]

I manually downshift my 92 and it hasn't seem to hurt anything. The owner's manuals says you can manually downshift but I would think that if you don't do it so that downshifting will bring the engine up to close to full throttle, there should be no problems.

I usually don't shift up into OD until 50MPH. Sometimes I will leave the lever in 2 at speeds of 25 or lower then shift up to D. I do shift between D and 2 on occasion in city driving and that helps control the car especially on hills. I will also shift from OD to D when exiting a freeway.

As long as you have clean tranny fluid and have the tranny filter serviced every so often it should not be a problem. I upgraded my tranny to synthetic fluid when I had a complete flush and new filter done last year.

 

[tlong]

If they didn't want us to play with that big ol' honkin' stick they should have made push buttons. Thanks for your opinion. Not trying to substitute for a 6 speed, just want to know if I'm killing the trans decellerating with a lower gear.

 

[RedRagTop]

I don't downshift aggressively. I leave it in D when in town and OD on the highway but usually shift it down when stopped. Unless the grin factor is worth the potential wear I likely wouldn't advise it all the time.

 

[WhalePirot]

The deceleration energy has to go somewhere. I try to unload the driveline by blipping the throttle, whichever tranny type I am driving. This decreases the slowing factor by allowing only engine compression to slow the car, but alos saves tranny clutches, U-joints, etc. from increased loads (wear). I think it is less about whether you downshift and more about how you do it.

 

[koolaid117]

The deceleration energy has to go somewhere. I try to unload the driveline by blipping the throttle, whichever tranny type I drive, which decreases the slowing factor by allowing only engine compression to slow the car, but saves tranny clutches and U-joints, etc. from increased loads (wear). I think it is less about whether your downshift and more abou how you do it.

Huh? Can you explain that better, please? I think I get it, but I'm not sure.

Thanks!

 

[G Winter]

Should be about the same as shifting up under power. No reason not to do it other than you put reverse load on the engine, sometime causing it to pull some oil into the cyl. which wouldn't be much . I have done it for yrs with many of my cars. Never caused me a problem .

 

[WhalePirot]

Sorry. Matching engine RPM to the RPM required (blipping the throttle) in the newly selected gear takes any 'shock' loads off of the driveline components. Those loads are the ones that move your passengers' heads forward. Proper 'blipping' would see no heads move and any deceleration is accomplished using engine compression only. It is a simple technique, involving timing and knowledge of the car's shifting characteristics.

Just as brake parts wear by changing the mechanical force of the car into heat (and brake dust), that same energy can be channeled through the transmission and every component of the driveline by decelerating with downshifts and not brakes. Improper downshifts shift that energy from the brake system to the driveline, wearing away small amounts of material in the transmission clutches, gears, and every part rubbing another part, lubrication not withstanding.

Some stick shifters slip the clutch to slow the car, which is totally wrong. I remember a wise old hot rodder advising me that, "It is cheaper and easier to change brakes than clutches." (Aren't the cars built that way?) Downshifting an automatic in a similar manner is harder on the tranny than not, but it will likely not show up for some time.

Surely this happens every time shifts happen, but we control how severe the shift is and how often they occur, and pay for repairs accordingly.

 

[tred95]

I manually shift the auto in certain situations. I live in central Pa. and there are a lot of hills. So as I'm ascending a long hill when the transmission shifts into a lower gear, I manually select it to hold it in that gear so it doesn't keep trying to shift back and forth. Then on descending I leave it there to use the engine braking.

 

[tlong]

This is the best auto tranny I've ever driven and don't want to break it. Accidently went into 2 at about 75 and hit the rev limiter etc. After not blowing the engine or tranny afterwards to my surprise no ill effects. I'll ease it into a lower gear for sure if necessary.

BTW best AC, best heater, (manual controls) best seats and best looking car I've ever had along with the sweet trans. 2nd is tall and strong in the mountains, D just perfect for 45 limit in the burbs, OD good to 172.

 

[Tim Scales]

I usually downshift from OD to D in heavy traffic to help"save the breaks" and in trveling down "Steep Mtn. grades" to help save breaking. Especially in the Blue Ridges, appalachians or the Rockies and have never had any "Ill effect". I have almost 118,000 on my '92 4L60E. Occaisionally I will upshift from 1-2-D-OD on heavy acceleration but not on a regular basis. But I would reccommend to always drive it in OD if your not in super slow city traffic due to the amount of increase in RPM's ETC. Saves engine wear-N-tear, uses LESS of that Liquid GOLD as well.

 

[tlong]

I read somewhere that the LT-1 should not be in OD at slow speed because low rpms starve it for oil. Who knows.

 

[Robertwav1]

Someone mentioned to me that taking it out of OD can actually add to the trans life especially at speeds below 2K RPM. I use this as a reference when I'm driving rather then speedo. All that shifting at speeds in between is wear and tear on the trans. I blew an automatic once....(not in a vette) downshifting from a higher gear! Fear has always kept me from attemting that again.