Reply With QuoteI think until your going fast enough for the torque converter to lock it will drop the revs. Torque converter locks up around 80kmh, does yours do it above that speed. I have a 95 tdi auto but it's not on the road yet so I'm just guessing.
YarnMaster
When I drive the auto, the revs fall away to idle when I completely remove my foot from the accelerator. Then when I put the foot down again it resumes as per normal... Is it normal that the revs fall to idle? its unlike other automatic cars I've driven (ie commonwhores and fords).
Master
I think until your going fast enough for the torque converter to lock it will drop the revs. Torque converter locks up around 80kmh, does yours do it above that speed. I have a 95 tdi auto but it's not on the road yet so I'm just guessing.
RoverLord
normal, depending on how fast your going when you do it.
when you lift off of the loud pedal the throttle sense cable lets the gear box know that it can start to shift up gears which it will do and as theres isnt enough speed on the first speed sensing bit of the gearbox (which is hooked up directly to the TC and is soley in control of locking up the torque converter) this will let the engine drop to idleish speeds.
it wont do it if the TC is already locked up as the engine is mechanically linked to the box as opposed to the fluid coupling of the TC. but once road speed slows enough for the TC to unlock as soon as it does the revs will drop again.
this goes for all autos if you leave them in D for Dummy.
if you knock it back to one of the numbered gear ranges it should hang onto the tallest gear for substantially longer.
you can make it hang on longer by adjusting the throtte sense cable to make it think that your on the loud pedal harder than you really are but then it will shift up later as well.
and finally if the TC has been replaced by one that has a higher than standard TC stall speed or if you have the v8s TC adapted to the TDI (yes it can be done ask 51jay).
All of that said....
IF the TC lockup control solenoid isnt doing its job your not locking the TC and thats not cool. id you have a slipping clutch pack you will get these symptoms (but there should also be others) and if your lowish on oil it can happen but it should also let the engine rev its biscuts out when you try to take off really hard or when you do a stall test.
Dave
"In a Landrover the other vehicle is your crumple zone."
For spelling call Rogets, for mechanicing call me.
Fozzy, 2.25D SIII Ex DCA Ute
TdiautoManual d1 (gave it to the Mupion)
Archaeoptersix 1990 6x6 dual cab(This things staying)
If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
If you think you're in front on the deal, pay it forwards.
LordRover
SubscriberAll auto's drop the revs when you back of the loud pedal as the converter is effectively dis engaging drive then when you boot it again the revs will rise till it engages again near where it left off. You will also notice how when you do back off how quiet it is almost like its not running at all.
MY08 TDV6 SE D3- permagrin ooh yeah
2004 Jayco Freedom tin tent
1998 Triumph Daytona T595
1974 VW Kombi bus
1958 Holden FC special sedan
YarnMaster
Yep, and discover how noisy the tyres areOriginally Posted by loanrangie
Master
G'day loanrangie,
With due respect, this is not generally true, as it really depends on the programming of the gearbox.
In a Discovery Series II V8, which has the same auto gearbox (ZF4HP22) as the TD5, the behaviour of the two boxes couldn't be different. I've driven both extensively in multiple vehicles, and also towed with both, and they are like chalk and cheese in behaviour.
In the V8, the auto gearbox is programmed by Land Rover to maximise fuel economy, so it likes to get to the highest gear quickly and lock the torque converter and keep it locked for as long as it can. So sometimes I find that I'm losing speed going up a hill because the torque converter has allowed the V8 to drop out of its power band, lugging up in top gear, locked and with 1200 rpm on the tacho.
The TD5 settings for the same gearbox is to unlock the torque converter when revs drop below 1800 rpm (sometimes higher). I am guessing that LR intentionally did this so that it will allow the TD5 to spool up the turbo quicker because the torque converter is allowing the engine to rev quickly. Which is why auto TD5s always seem to have a lot more NVH than manual TD5s - because most manual drivers would shift at lower rev points on their Discoveries or Defenders.
Anyway, back to the original topic. The auto gearbox in the 300TDi will probably stay locked at the higher rpm (lock features only in 3rd and 4th gears on the Discovery auto implementation, no lock available in 1st or 2nd). But when the revs drop, the torque converter just unlocks.
Perfectly normal.
BTW, to Joel, from a maintenance point of view, do change the ATF regularly and the gearbox will last a lifetime. So if it hasn't already been done recently, just dump the ATF and refill following the correct procedure. These gearboxes have clutch packs that are not very tolerant of burnt fluid or contamination from water ingress....
Lawrance
Posting Permissions
| Search AULRO.com ONLY! |
Search All the Web! |
|---|
|
|
|
Bookmarks