| Author | Message | ||
     Sus (Susannah) Senior Member Username: Susannah Post Number: 409 Registered: 06-2002 |
HAHAHA, okay, so I couldn't resist! I have been in a few heated 'discussions' with my father and other MEN I know about this...so I need an answer: When you are shifting gears on an automatic, does it damage the •••••• to shift through neutral without bringing the car to a complete stop? My dad's always been one of those shift while moving types....and others have told me you should break and stop completely before changing... What's the TRUTH?  | ||
| Steve Andrews (Sillybus) Member Username: Sillybus Post Number: 185 Registered: 08-2002 |
I definately have no clout to speak on this but I've always been led to believe the same thing. If you shift while moving I've been told its hard on your transmission. | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 510 Registered: 02-2002 |
Sus that's not a dumb question, I've often wondered myself, because sometimes when you're stuck in mud its very useful to be able to rock your way out of the stuff by alternating 1st and reverse quickly. I have done it a very very low speed, but that's all. Seemed ok then. Dean | ||
| joshua Frances (Joshua) Member Username: Joshua Post Number: 98 Registered: 10-2002 |
are you talking about shifting "on the fly" like, the 4wd shifter? | ||
| Mark Albrecht (Markalbrecht) Member Username: Markalbrecht Post Number: 54 Registered: 11-2002 |
OK, I'm may be feeding you hooey, but I think it depends on whether you have synchronized gears (usually first and reverse) -- for when you're rocking in mud. | ||
| Eric N (Grnrvr) Senior Member Username: Grnrvr Post Number: 1240 Registered: 02-2002 |
I would think that anytime you apply force in one direction and then suddenly apply force in the opposite direction without the object coming to a stop is probably not a good thing on the gears and other drive line parts. However, I don't know anything so don't listen to me. | ||
| phil (Powerslide) Member Username: Powerslide Post Number: 43 Registered: 11-2002 |
There are no stupid questions and you are welcome to ask. Now as for an answer, there are many valves (hydraulic and also mechanical)inside the autotrans controlling the gearsets and flow of hydraulic fluid so it is a good practice to not shift to neutral until the car/truck is stopped. You will also note that the shifter was designed such that neutral is in between reverse and drive as a safety margin to avoid excessive shock and wear. And as for Park, the car should be really stopped because it can damage the locking pins on the transmission if it is engaged while in motion. Just my 2 cents. Cheers. | ||
| Max Thomason (Lrmax) Member Username: Lrmax Post Number: 91 Registered: 11-2002 |
I do remember a long time a go (in a far away galaxy), a RRC owner had a few problems with this... Whenever the RRC driver would reverse, before the vehicle had stopped, he would shift the vehicle in drive and then continue on. If my memory serves me correctly, this lead to his CV (or UJ, I don't remember whats on RRC) to get screwed up. So whenever he would park the vehicle on a hill, it would roll downhill. So, Sus, I think you should always come to a complete stop before shifting the vehicle in another gear. Max T. Oh yea, it took place in THIS galaxy..... | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 34 Registered: 11-2002 |
All I got to say is imagine a dog running at full steam and then running out of leash. That should explain it well enough.. Kyle "Blow me" | ||
| Yaroslav (Andr6761) New Member Username: Andr6761 Post Number: 28 Registered: 07-2002 |
automatics were designed to slip....especially on rovers...but it does decrease the life on the transmission.... | ||
| Jaime (Blueboy) Senior Member Username: Blueboy Post Number: 545 Registered: 02-2002 |
lol! good analogy Kyle. living in snow country most of my life and driving heavy American iron with rear wheel drive, rocking the car to get unstuck was a technique you had to learn. key was the timing in shifting back and forth to get the car a rockin'. let up on the go peddle just as the car almost stopped going one way, wheels not spinning, shift into the other direction, and repeat. if you didn't dig down to far to begin with, you usually could get out. that coupled with others helping. we never had a transmission problem on the cars. its way too easy in a LR. Jaime | ||
| Greg Davis (Gregdavis) Senior Member Username: Gregdavis Post Number: 662 Registered: 08-2002 |
When you say "through nuetral", you mean from D to P, etc., without stopping, or just going into nuetral? I ALWAYS come to a complete stop before going from anyting into either P or R. However, I will shift into N while moving to engage 4 Lo or trying to get my CDL to disengage. | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 514 Registered: 02-2002 |
First of all you definitely CAN go into neutral while moving, because that's how you're supposed to engage low ratio, although the sticker suggests 5 mph maximum. I do not know this for a fact, but I assume the reverse and 1st gears are synchromeshed? So while rolling backwards, when you engage 1st gear, the relative speed of the thrust plates will be reduced until they are matched. Is this different internally from starting from stationary? Dean | ||
| Sus (Susannah) Senior Member Username: Susannah Post Number: 412 Registered: 06-2002 |
Let me clarify a bit.... I'm not relating this question to 4wd locking (I know how that works) or even Rovers in specific. Just any automatic car... Say I reverse out the driveway, apply brake a little, shift from R to N into Drive without stopping absolutely completely? And then vice versa, driving slowly (under 5mph) brake slightly, N then R....this is mostly in parking/unparking conditions. I just want to know if it really tears up your transmission. I would never shift into PARK while MOVING!! THanks for all the input so far. | ||
| Greg Davis (Gregdavis) Senior Member Username: Gregdavis Post Number: 665 Registered: 08-2002 |
Well, if you're rolling forwards while in N and then go into R, then I would say that's bad. Try to make sure that you're not moving in the opposite way that you're getting ready to shift into, and you'll be fine. | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 519 Registered: 02-2002 |
I'd agree with you Greg, but I think Sus wants to know why? Actually, so do I I mean when the engine speed is low, there's not really much friction between the plates right? So if you're going a few mph in the opposite direction, then the relative speed of the plates will be higher, but is that such a big deal? Its not like you're stepping on the gas burning off the mustang! | ||
| phil (Powerslide) Member Username: Powerslide Post Number: 45 Registered: 11-2002 |
Sus, Do you experience a jolt when you shift from Drive to Reverse and vice versa? I bet you do in varying degree and this will not break your transmission immediately but over time IMO it will reduce the life by increased wear and tear. However, if you must, it is your choice to continue to drive this way and perhaps nothing will happen. A long time ago, my in-law had a Toyota Cressida and the •••••• crapped out prematurely and the Toyota mechanic said that shifting from reverse to drive and vice versa while still in motion caused premature wear. My mother-in-law admitted to this habit. | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 36 Registered: 11-2002 |
The transmissions are really not designed to slip and they shouldnt. The converter however slips alot. If you saw the size of some of the parts in an auto and how small they really are this post would end abruptly. Its not good to do for many reasons. The poor planetary set gets the hell banged out of it. And all of the stampde steel parts that are riding on spline and the aluminum parts that are riding on spline pretty much dont like it. Not to mention the U joints and diffs.... Kyle "Blow me" | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 37 Registered: 11-2002 |
Syncromesh Dean ??? lol.... Um,,,,,,NO! Kyle "Blow me" | ||
| Peter Matusov (Pmatusov) Senior Member Username: Pmatusov Post Number: 500 Registered: 09-2002 |
Sus, thumbs up for the thread name. Kyle chimed in after 8 posts or so, way under his own noise level. don't do it, or you will end up with transmissions and t-cases like in 3 of my trucks (all i owned for a while) - which produce a loud bang while switching from D to R and/or back, and loud clunk at every coasting/acceleration transition. peter | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 522 Registered: 02-2002 |
Kyle, I don't know the terminology obviously (I thought it was called synchromesh) but whatever its called it brings the driven and driving plates up to matched speed gently. That's the part I meant. Could you enlighten me by throwing together a quick 3D stereoplan? | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 38 Registered: 11-2002 |
Thats on Manul transmissions man. The auto uses hydraulic pressure to engauge and disengauge different drums to shift to a different gear. How they do this is a little different in differnt transmissions. Musky will probably chime in here but this is why some transmissions are faster then others. Hard to explain but for instance Trans "A" takes off in first gear , the actions that need to take place to shift to second are a band applying , a drum dropping out and another drum coming in. Trans "B" takes off in first gear and to shift to second only needs to apply another drum... Trans B is much more efficient and a faster shifting trans. It will also live longer. (Musky , can you gues what those two were??? Kyle "Blow me" | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 523 Registered: 02-2002 |
You're right Kyle that was on a manual that I farted around with. I just assumed amusingly that an auto did the same thing internally LOL. Well, that's how I would have designed it anyway So which type has the disco got? | ||
| Kyle Van Tassel (Kyle) Moderator Username: Kyle Post Number: 39 Registered: 11-2002 |
The Disco would be more like B.... Kyle "Blow me" | ||
| Carter Simcoe (Carter) Senior Member Username: Carter Post Number: 1956 Registered: 04-2002 |
Thats interesting stuff Kyle, would a chevy be an 'A'???: | ||
| Joey Cox (Joey_cox) New Member Username: Joey_cox Post Number: 14 Registered: 02-2003 |
The correct terminology is synchronized. As Kyle said, this pertains only to manual transmissions. As far as shifting from drive to reverse in with an automatic, don't do it. Joey | ||
| Ron Brown (Ron) Member Username: Ron Post Number: 92 Registered: 04-2001 |
ZFs don't have bands, 727s do but are still good trans. Those the two you were thinking of there Kyle? Ron | ||
| john baker (Johnb) New Member Username: Johnb Post Number: 15 Registered: 11-2002 |
living here in vermont with ice and snow,and stuck vehicles,and being that i manage a transmission repair shop,i see alot of ruined transmissions.the trans takes it pretty hard doing the fwd to reverse thing,along with the rest of the driveline.it is possible to get away with that action somestimes,but the odds are aginst you.call a tow truck to get unstuck,or to get you unstuck and to the repair shop.but on the other hand,i need to keep working..... | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 525 Registered: 02-2002 |
From the D2 shop manual: The transmission gear changes are electronically controlled. 1. The transmission will not engage reverse gear below 5 mph. 2. The transmission will not disengage from reverse below 4 mph. Its not clear to me whether (1) is talking about travelling forwards or backward though. Anyone here care to enlighten? So on this basis Sus you could theoretically slam into reverse even at highway speed and nothing would happen. There was however, no mention of the ECU limiting gear changes that would blow up the engine (going into 1st at 90, for example.) But I'd still agree its a bad thing, even at less than 5 mph, and personally I have never been able to rock a 4x4 out using alternate 1st/rev gear changing, although I have done several times in a manual 2 wheel drive in mud. Dean | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 526 Registered: 02-2002 |
Ps Kyle thanks for allowing us to use the word 'transmission' | ||
| Rob Davison (Nosivad_bor) Senior Member Username: Nosivad_bor Post Number: 83 Registered: 02-2003 |
ok, how about this... i am stuck in the snow and i need to rock the truck because i sold my winch. this can be achieved buy giving gas and then letting off in a rhythm, the car will lurch and you let off and it rolls back into the spot... keep repeating. i never shift into opposite direction, but i still fell like it's slightly destructive to the trans. how bad is that? how bad is it to do that in reverse gear rather than say 1st gear? -rob | ||
| Jaime (Blueboy) Senior Member Username: Blueboy Post Number: 554 Registered: 02-2002 |
see my post Rob, as I said the same thing. must be a W.PA. driving thing. never hurt our cars in the past. possibly the LR is different. Jaime | ||
| Peter Matusov (Pmatusov) Senior Member Username: Pmatusov Post Number: 502 Registered: 09-2002 |
Rob, you don't need to get the "rhythm" thing going for it. Drive as far (it may be a matter of inch or less) forward as you can, slam on brakes (on a fancier rover, it means disabling ABS first), flip into reverse, go as far back as possible, slam on brakes, etc. there's really little excuse for flipping from D to R without stopping the wheels first. all said, i've backed down a long steep hill in the 1st gear, low range. It was the only way for me to keep the control of the truck. Didn't seem to have had any negative effect on the transmission - which I suspect doesn't belong to the efficient Type B peter | ||
| Rob Davison (Nosivad_bor) Senior Member Username: Nosivad_bor Post Number: 85 Registered: 02-2003 |
jamie i am to lazy to srcoll up, can you cut and paste it down here lol ok, i read it. you mention "shifting" into another direction. i dont do any gear shifting. we on the same page? good rob "blow kyle" | ||
| Eric Thatcher (Desertdork) New Member Username: Desertdork Post Number: 2 Registered: 02-2003 |
An automatic trans has several hydraulic actuated multi plate clutches that connect different gear sets that are constant mesh (no need for syncros). Flipping from a forward gear to reverse makes little difference to these clutch packs, they are designed to handle speed differences from any point of reference. The part of the transmission which is effected is the torque converter. If the vehicle is moving forward and the transmission engages the reverse gear set... the input shaft on the transmission will turn the torque converter backwards... and it will transfer some load to the engine. The engine will lug, perhaps stall a bit... that is the worst that will happen at low speeds 10mph or less. Same thing happens when you are giong up a hill in first, let of the gas, and begin to roll backwards while still in gear... the engine lugs and stalls a bit. I don't think the internal hydraulic circuits will allow the clutch to engage the reverse gear set over a certain speed in most transmissions. And the torque converter is not very good at transferring load in the reverse direction, which makes it real hard to push start an automatic. | ||
| Jaime (Blueboy) Senior Member Username: Blueboy Post Number: 555 Registered: 02-2002 |
RD, we always did gear shifting as we rocked the car. forward in drive, almost come to a stop, wheels barely spinning, shift into reverse, go backwards, almost come to a stop, wheels barely spinning, repeat. people pushing usually in the opposite place you're trying to go. don't know if a LR can handle it, yet, all the past vehicles I've owned over the years certainly have without any transmission problems. key is the rythm. Jaime | ||
| Sus (Susannah) Senior Member Username: Susannah Post Number: 414 Registered: 06-2002 |
Oh my god...I have learned SOOOO much about transmissions!! I posted a reply a while back, but was kicked off and it doesn't seem to have gotten through. I don't do that shifting while moving stuff much, but I learned it from my dad. He has ALWAYS done it, and he has a Dodge van that's •••••• blew at 60K. Now, I'm not sure if it was the car or the company or him...my fiance's dad had a Plymouth van that did the same thing. But my dad hasn't had trouble with any of our other cars (Cadillacs, Mercedes and BMWs mostly). I just wondered how much it really plays a part. Now, I COULD feel a 'jolt' when doing this, but I know that's BAD...so I usually let the shift into neutral slow the vehicle enough before shifting again--we are talking like NEGATIVE mph at this point. Maybe I just want a manual so I can feel interactive with my transmission! ;) | ||
| Eric N (Grnrvr) Senior Member Username: Grnrvr Post Number: 1242 Registered: 02-2002 |
Sus, if you want that manual feel you can always start at D1 and shift up as you go.. |
