robbie, I don't know anything about transmission internals - what's a valve body, where is it, and why is it a weak point? Do you really mean to just get a rebuilt one or do you mean to get an aftermarket?
Sorry 'bout the thread hijack.
Nic
Downshifting
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robbie, I don't know anything about transmission internals - what's a valve body, where is it, and why is it a weak point? Do you really mean to just get a rebuilt one or do you mean to get an aftermarket?
Sorry 'bout the thread hijack.
Nic
I never do it other than turning the OD off in our 94. But I shift our 91 almost like a manual. I always start in 3rd and let it shift 1-3, then if I need OD I shift it up. If I'm coming to a stop and need to slow down fast. I'll drop it from 3rd to 2nd. Never at extreme rpms, and the valves wouldn't let it shift if the RPMs are too high anyway. My fluid is always pink. No weird noises or problems. I've got almost 200k on it and it doesn't seem any different than when it had 56k on it.
[quote author=cruiserdan link=board=2;threadid=12059;start=msg110689#msg110689 date=1077768889]
Better than a motor
I think that between the 2 of us, we could have one out in about 6 hours
[/quote]
Yea verily.
Better than a motor
I think that between the 2 of us, we could have one out in about 6 hours
[/quote]
Yea verily.[quote author=IdahoDoug link=board=2;threadid=12059;start=msg110737#msg110737 date=1077772991]
I suspect mine is performing closer to new than nearly anyone's due to strong maintenance. [/quote]
Blah blah blah :
I suspect mine is performing closer to new than nearly anyone's due to strong maintenance. [/quote]
Blah blah blah :
[quote author=robbie link=board=2;threadid=12059;start=msg110891#msg110891 date=1077807955]
If leaving the tranny in drive all the time you let the truck drive you, using brakes in a corner is a no no, the truck is driving you, down shift and power through the corner for better control. Auto's are nice but create a lazy not on top of conditions drivers (pet peeve)[/quote]
Using the brakes in a corner is no-no?!!!! what about when I am trail braking to set the car up for a nice 4 wheel drift? I am braking while turning though the corner, even though my braking is performed before the apex. Also, I am sorry, but unless you are running a lapping day or road racing, you do not need to be manually rowing through the gears on your automatic transmission. It just puts unecessary wear on them.
If automatics create lazy drivers, what to paddles shifters create? Semi-Lazy F1 drivers?
Cary
If leaving the tranny in drive all the time you let the truck drive you, using brakes in a corner is a no no, the truck is driving you, down shift and power through the corner for better control. Auto's are nice but create a lazy not on top of conditions drivers (pet peeve)[/quote]
Using the brakes in a corner is no-no?!!!! what about when I am trail braking to set the car up for a nice 4 wheel drift? I am braking while turning though the corner, even though my braking is performed before the apex. Also, I am sorry, but unless you are running a lapping day or road racing, you do not need to be manually rowing through the gears on your automatic transmission. It just puts unecessary wear on them.
If automatics create lazy drivers, what to paddles shifters create? Semi-Lazy F1 drivers?
Cary
[quote author=cary link=board=2;threadid=12059;start=msg110928#msg110928 date=1077810779]
Also, I am sorry, but unless you are running a lapping day or road racing, you do not need to be manually rowing through the gears on your automatic transmission. It just puts unecessary wear on them.
If automatics create lazy drivers, what to paddles shifters create? Semi-Lazy F1 drivers?
Cary
[/quote]
I want a definition of unecessary wear. How is it measured? I mean if you go 200k and it drives the same as it did at 56k where is this wear? I'm not taking it apart if it isn't broke. And when I drive my 91 at times I feel the need to shift in manually to get the most out of each shift. It keeps the engine where it needs to be. And the constant shifting between overdrive and 3rd is what causes heat. Heat kills autos. Manually shifting prevents the constant shifting.
Also, I am sorry, but unless you are running a lapping day or road racing, you do not need to be manually rowing through the gears on your automatic transmission. It just puts unecessary wear on them.
If automatics create lazy drivers, what to paddles shifters create? Semi-Lazy F1 drivers?
Cary
[/quote]
I want a definition of unecessary wear. How is it measured? I mean if you go 200k and it drives the same as it did at 56k where is this wear? I'm not taking it apart if it isn't broke. And when I drive my 91 at times I feel the need to shift in manually to get the most out of each shift. It keeps the engine where it needs to be. And the constant shifting between overdrive and 3rd is what causes heat. Heat kills autos. Manually shifting prevents the constant shifting.
[quote author=ginericfj80 link=board=2;threadid=12059;start=msg110982#msg110982 date=1077814167]
I want a definition of unecessary wear. How is it measured? I mean if you go 200k and it drives the same as it did at 56k where is this wear? I'm not taking it apart if it isn't broke. And when I drive my 91 at times I feel the need to shift in manually to get the most out of each shift. It keeps the engine where it needs to be. And the constant shifting between overdrive and 3rd is what causes heat. Heat kills autos. Manually shifting prevents the constant shifting.
[/quote]
Now you are talking about holding a gear rather than downshifting an automatic and rowing it as if it were a manual. When you hold a gear, you are not causing wear. Forcing a downshift is causing the trans to have to change gears and utilize the clutches to match the gear speeds under power and causes excessive wear (remember the trans doesn't care if you are putting power under throttle or engine braking, one is just power in the opposite direction of the other). Compare this to a light load downshift when comming to a stop at low RPM.
BTW, a transmission hunting from 3rd to 4th does not create heat from the shifts. It creates heat because the torque converter is unlocked and the energy being absorbed by the converter is being converted to heat. The shift itself takes less than 1/2 second and uses little energy. The reason to lock out overdrive on a long climb (at least in the 95+ LC) is that the transmission will then lock out the torque converter in 3rd gear and lower the amount of heat. This does not happen if you leave it in drive and it automatically shifts to third gear.
If you want to convince yourself that rowing through the gears to downshift when coming to stop does not cause wear on the trans, go ahead. It is your money for a new trans sooner.
Cary
I want a definition of unecessary wear. How is it measured? I mean if you go 200k and it drives the same as it did at 56k where is this wear? I'm not taking it apart if it isn't broke. And when I drive my 91 at times I feel the need to shift in manually to get the most out of each shift. It keeps the engine where it needs to be. And the constant shifting between overdrive and 3rd is what causes heat. Heat kills autos. Manually shifting prevents the constant shifting.
[/quote]
Now you are talking about holding a gear rather than downshifting an automatic and rowing it as if it were a manual. When you hold a gear, you are not causing wear. Forcing a downshift is causing the trans to have to change gears and utilize the clutches to match the gear speeds under power and causes excessive wear (remember the trans doesn't care if you are putting power under throttle or engine braking, one is just power in the opposite direction of the other). Compare this to a light load downshift when comming to a stop at low RPM.
BTW, a transmission hunting from 3rd to 4th does not create heat from the shifts. It creates heat because the torque converter is unlocked and the energy being absorbed by the converter is being converted to heat. The shift itself takes less than 1/2 second and uses little energy. The reason to lock out overdrive on a long climb (at least in the 95+ LC) is that the transmission will then lock out the torque converter in 3rd gear and lower the amount of heat. This does not happen if you leave it in drive and it automatically shifts to third gear.
If you want to convince yourself that rowing through the gears to downshift when coming to stop does not cause wear on the trans, go ahead. It is your money for a new trans sooner.
Cary
R
robbie
Guest
Well we all have our own driving style, I would think we are not F1 drivers either. Nor is the crusier a F1 race car(most of those F1 drivers have way better skills and training). Maybe with ABS which most have now days braking still allows a person to steer through the corner, but most drivers do not have the skills you may have.
Yes what do you mean by unecessary wear? Remember these are not american tranny designed only to last 80 to 100 k (except the new alison), before it gives you greif. Most people will not hurt the auto in a cruiser except through not following the care and feeding of the critter you drive. later robbie
Yes what do you mean by unecessary wear? Remember these are not american tranny designed only to last 80 to 100 k (except the new alison), before it gives you greif. Most people will not hurt the auto in a cruiser except through not following the care and feeding of the critter you drive. later robbie
Extra wear on the tranny from manual down shifting? I have to add my two cents here. Ok, I am driving down the road coming up to a stop light. Vehicle in "D", I start to brake to decelerate. Does the tranny not also down shift on its own once you hit a certain rpm? Or once I hit the brake, the tranny goes into neutral? I think not. The tranny is designed so even if you are clueless and down shift at too high an rpm it won't actually down shift until it gets to a certain safe rpm. This is what they are designed for. The difference (relativily speaking) between and auto and manaul is the clutch and the only reason for the auto was for people that couldn't drive a clutch.
What will tear up your tranny is heat from over working it, not keeping filters/oil in good condition, or doing neutral drops into drive and reverse, you know when you are stuck and trying to rock your rig free.....
No, I am not a tranny man (I am a tits and ass man :), but this is how I see it.
Yomama
What will tear up your tranny is heat from over working it, not keeping filters/oil in good condition, or doing neutral drops into drive and reverse, you know when you are stuck and trying to rock your rig free.....
No, I am not a tranny man (I am a tits and ass man :
), but this is how I see it. Yomama
Yomama,
Man haven't seen you in a while. Yes, the tranny does downshift when slowing down and stopping. However, it is shifting under nearly no load, i.e. a nice easy shift, versus manually pulling it down each gear at higher RPMs is going to force a shift under load (see my above comment about engine braking). The trans has to slip the clutches more to sincronize under a load shift than a no load, hence extra wear.
Cary
Man haven't seen you in a while. Yes, the tranny does downshift when slowing down and stopping. However, it is shifting under nearly no load, i.e. a nice easy shift, versus manually pulling it down each gear at higher RPMs is going to force a shift under load (see my above comment about engine braking). The trans has to slip the clutches more to sincronize under a load shift than a no load, hence extra wear.
Cary
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I have an acute interest in this subject, since we're building on a mountainside in western NC. The gate for our comunity is about 2600 feet, and our lot is just under 4000. The ridgeline behind my house tops out above 6000 -- not much for Colorado, but that's a lot for the Blue Ridge.
At present, when I drive to the building site each day I'm driving up the mountain in third (OD off) or in second gear, to keep the transmission from upshifting to third and OD when I'm coasting into a hairpin, then lugging in OD or third with RPMs falling from 1900-1500 before it downshifts to second.
Going down the mountain, I leave the transmission in second for some mild engine braking. The brakes fade a little when they get hot, and the mild engine braking seems enough to prevent the fade.
This is certainly "extra" wear on the transmission -- but it's just another cost of living in the mountains, like more frequent brake pad replacement. And it's one more reason I bought a Toyota Land Cruiser - they're not indestructible, but they are the closest thing to it that I've seen yet.
LT
At present, when I drive to the building site each day I'm driving up the mountain in third (OD off) or in second gear, to keep the transmission from upshifting to third and OD when I'm coasting into a hairpin, then lugging in OD or third with RPMs falling from 1900-1500 before it downshifts to second.
Going down the mountain, I leave the transmission in second for some mild engine braking. The brakes fade a little when they get hot, and the mild engine braking seems enough to prevent the fade.
This is certainly "extra" wear on the transmission -- but it's just another cost of living in the mountains, like more frequent brake pad replacement. And it's one more reason I bought a Toyota Land Cruiser - they're not indestructible, but they are the closest thing to it that I've seen yet.
LT
Wow, lots of differences here on a topic I'd thought was quite cut and dried.
If you're simply holding gears longer by shifting up manually, I can't see more than an incremental increase in wear. That wear would simply be due to the engine shifting at whatever higher RPM than stock shift points you're choosing and the resulting higher torque the clutches and such must deal with during the shift. Very minor though.
But I'll side with Cary in that the description of "rowing" through the gears and comments about routinely using the transmission to actively slow the truck (vs holding a gear on a downhill) are going to increase wear on the transmission vs using the brakes to stop. How does this wear occur? Understand first that when brakes stop you, they're merely converting forward momentum energy of the truck into heat energy. When you downshift and the truck slows from this, you've just converted some forward momentum energy into heat in the transmission. The exact same amount of heat that would have made your rotors too hot to touch just went into the transmission.
You've also caused the clutches to cycle under load while downshifting instead of letting the transmission downshift as you came to a stop with nearly zero load as it's designed. So, a transmission used this way would undergo far more shifting under load, plus have far more heat cycles than a transmission left in D. Will it destroy the transmission in a day or a week? Certainly not - the 80 autos are very tough and can take it. But will it cause more wear on the transmission? Absolutely.
DougM
If you're simply holding gears longer by shifting up manually, I can't see more than an incremental increase in wear. That wear would simply be due to the engine shifting at whatever higher RPM than stock shift points you're choosing and the resulting higher torque the clutches and such must deal with during the shift. Very minor though.
But I'll side with Cary in that the description of "rowing" through the gears and comments about routinely using the transmission to actively slow the truck (vs holding a gear on a downhill) are going to increase wear on the transmission vs using the brakes to stop. How does this wear occur? Understand first that when brakes stop you, they're merely converting forward momentum energy of the truck into heat energy. When you downshift and the truck slows from this, you've just converted some forward momentum energy into heat in the transmission. The exact same amount of heat that would have made your rotors too hot to touch just went into the transmission.
You've also caused the clutches to cycle under load while downshifting instead of letting the transmission downshift as you came to a stop with nearly zero load as it's designed. So, a transmission used this way would undergo far more shifting under load, plus have far more heat cycles than a transmission left in D. Will it destroy the transmission in a day or a week? Certainly not - the 80 autos are very tough and can take it. But will it cause more wear on the transmission? Absolutely.
DougM
>>The exact same amount of heat that would have made your rotors too hot to touch just went into the transmission.
Actually it is the engine itself that is ultimately slowing down the vehicle not the transmission. The transmission just changes the gear ratio. Once the transmission has shifted into the lower ratio the wear on the bands is over for the most part. Sure you still have the bands keeping the transmission in its gear ratio, but the wear from this shouldn't be anymore than the normal wear from acceleration and deceleration.
Doug, your last paragraph I believe summarizes the real problem with manually downshifting, which is why I always make sure that if I do manually downshift it better be at a speed that won't cause any lurching forward. (this is also so I can keep my lunch where it belongs)
Even with a manual transmission it's not right to downshift where it causes lurching forward, however in a manual you can rev match or slip the clutch to avoid this (the former being the preferred method for wear)
Actually it is the engine itself that is ultimately slowing down the vehicle not the transmission. The transmission just changes the gear ratio. Once the transmission has shifted into the lower ratio the wear on the bands is over for the most part. Sure you still have the bands keeping the transmission in its gear ratio, but the wear from this shouldn't be anymore than the normal wear from acceleration and deceleration.
Doug, your last paragraph I believe summarizes the real problem with manually downshifting, which is why I always make sure that if I do manually downshift it better be at a speed that won't cause any lurching forward. (this is also so I can keep my lunch where it belongs)
Even with a manual transmission it's not right to downshift where it causes lurching forward, however in a manual you can rev match or slip the clutch to avoid this (the former being the preferred method for wear)
Is it better to drop it in neutral braking to a quick stop? Seems to be. No load from the tranny to the engine when not "in gear".
Um,
I think everybody should pound the hell out of 'em often.
My number is 1-800-43..............Oh, nevermind
I think everybody should pound the hell out of 'em often.
My number is 1-800-43..............Oh, nevermind
R
robbie
Guest
If the transmission is design to take upshift under a load, why is it not design to take down shift under a load? A shift is a shift the clutches do not care if it is down or up shifting. Yes shifitng under a load will create some wear and I would hope the designers of the materials would take it under some consideration. (which they have) there are no bands in these trannies, it is all a clutch and plate design. Using thick steel plates and clutchs that have considerable grip material. I believe it is only programing of the electronic one that do not have better more controled down shifting. The new alison tranny behind the durmax has downshifting under load built in to the program, expecially under tow mode.
I do use my tranny to slow down some times but not all the time, I do not "pladdle slap" the tranny, but I do not see that much increased wear from doing it your self vs the tranny doing it. I do not advocate redline ups shifts to catch the decompression brakeing this will over time harm more than just the tranny. but again we all have different styles of driveing habits and needs. later Robbie
I do use my tranny to slow down some times but not all the time, I do not "pladdle slap" the tranny, but I do not see that much increased wear from doing it your self vs the tranny doing it. I do not advocate redline ups shifts to catch the decompression brakeing this will over time harm more than just the tranny. but again we all have different styles of driveing habits and needs. later Robbie
27Feb2004 (UTC +8)
I agree with the viewpoints of Robbie, that of using engine braking moderately to slow down the Cruiser and also taking care not to row the gears and over rev the engine. I do control the vehicle better that way.
However, late last year I talked to Marlin (http://www.marlincrawler.com) about it, and he advised me that engine braking is not really that good for your tranny and that you should use brakes as much as possible. He explained why but I forgot the exact details... all I think I understood then was about the unnecessary load on the coast side of the gears (?)... I think Marlin is just about the best authority to explain about trannies and all
I agree with the viewpoints of Robbie, that of using engine braking moderately to slow down the Cruiser and also taking care not to row the gears and over rev the engine. I do control the vehicle better that way.
However, late last year I talked to Marlin (http://www.marlincrawler.com) about it, and he advised me that engine braking is not really that good for your tranny and that you should use brakes as much as possible. He explained why but I forgot the exact details... all I think I understood then was about the unnecessary load on the coast side of the gears (?)... I think Marlin is just about the best authority to explain about trannies and all
R
robbie
Guest
It would be interesting to hear Marlins coments. The auto uses a couple of planatary gear sets that have a 1 sun gear and planatary gears (3 if I remember correctly) per plantary set. The sun gear then has three points of contacts over a manual box that usually only has one counter shaft and then transfer power through one point of contact vs 3 points of contact. So the Manual may have more problems then an auto in this regards to coast side of the gear. This makes most auto stronger than a manual. I do not know of any light duty manual transmissions that have twin counter shafts to spread the load out. THis is usually found in the bigger trucks. I do think thismight be more of a problem in the diffs then in the auto tranny. robbie