Haynes glitch on auto box information?

robwijnstok · 20th May 2009, 18:20

Today I was “reading” my Haynes Owners Workshop Manual 2006 edition.

On page 7B*2 I read under – 1 General information – that, “to improve economy, the torque converter has a ‘lock-up’ facility in all gears accept for the first, this feature is mentioned for the 75 and ZT. Other automatic gear boxes only have this facility in the top gear”.

My boss has a Jaguar X type 2.5V6 with nearly the same mileage and also from 2003 but not half as smooth as my 75, and much much more noisy… but there is in every gear (accept the first) definitely a lockup of the torque converter. After locking, if you are not too hard on the throttle, it stay’s locked. That’s something I would like to have on my 75!

I see/hear/feel my gear only locking in fifth gear, a glitch of Haynes? Or am I really missing something? In my auto box that is.

Rob.

Departed · 20th May 2009, 18:34

Lock up applies to the 75, but not in 1st.

It also doesn't happen if the gearbox fluid is cooler than 40C.

It's carefully controlled, so you may never know it's locked up. As you say, newer boxes tend to stay in lockup once locked, but older tunes tend to unlock as soon as you apply power, so it sounds like it was never locked.

robwijnstok · 20th May 2009, 20:41

Hmm, that is interesting.
I recognise that the gearbox fluid has to have a certain temperature before a "lock" is possible, still only in fifth gear that is. When I drive from work on the motorway it does not lock (gearbox cold) when I do 120km/h @ 2500rpm. After a couple of km from work when I exit the motorway roundabout and I gradually increase speed, the gearbox locks immediate when I am in fifth gear just over 102km/h and on that moment I see the rpm’s drop from 2200 to 2100rpm. When I am not hard on the throttle it does not unlock by speed increases, when harder on the throttle it will unlock. And getting harder on the throttle, and kick down will be performed. So this is all Ok.

In the other gears I never noticed any drop in rpm’s not with very slow (traffic cue’s etc.), slow or fast acceleration. I think when a torque converter lockup is done at a certain point you must see or hear that at least by some dropping of rpm’s. Mine does that not, so no lockup?

Any chance this can be proven by a T4 session by fault code(s)?

Rob.

jim_mcglynn · 20th May 2009, 20:44

Sorry for being a thicky, but what does "lock up" mean?

robwijnstok · 20th May 2009, 20:57

Sorry, that is locking of the torque converter in the auto gearbox. In that way there is no slip between engine and gear anymore. Driving that way is more economic, and the auto gearbox oil temperature will drop also.

StevenWilliams · 20th May 2009, 21:20

Thanks. You have answered a question I have been wondering for a while. I thought the behaviour of our cars meant it had an automatic overdrive. Now I understand.

When I'm driving and increasing speed after I hit 70 the revs are on about 2400RPM. After about 30 seconds the revs drop to about 2100. I thought it was an overdrive kicking in but it must be the lock kicking in.

RLeon · 21st May 2009, 10:40

Quote:

Originally Posted by robwijnstok

Hmm, that is interesting.
I recognise that the gearbox fluid has to have a certain temperature before a "lock" is possible, still only in fifth gear that is. When I drive from work on the motorway it does not lock (gearbox cold) when I do 120km/h @ 2500rpm. After a couple of km from work when I exit the motorway roundabout and I gradually increase speed, the gearbox locks immediate when I am in fifth gear just over 102km/h and on that moment I see the rpm’s drop from 2200 to 2100rpm. When I am not hard on the throttle it does not unlock by speed increases, when harder on the throttle it will unlock. And getting harder on the throttle, and kick down will be performed. So this is all Ok.

In the other gears I never noticed any drop in rpm’s not with very slow (traffic cue’s etc.), slow or fast acceleration. I think when a torque converter lockup is done at a certain point you must see or hear that at least by some dropping of rpm’s. Mine does that not, so no lockup?

Any chance this can be proven by a T4 session by fault code(s)?

Rob.

Hi Rob,

I experience the same with my car, noticeable drop with 100 km/h and backing of throttle. Every year my car has a service with a ex-Rover dealer who has the T4. Never had any fault code reported on the gearbox. I had a read in the workshop manual and in chapter 44 page 36 it is stated that lock-up is possible in gears 2,3,4 and 5. The EAT-ECU regulates this on position of throttle, speed, oil temp(>40 celsius) and to get a smooth lock-up change varies the oil pressure of the lock-up clutch. What I have noticed is that with lower speeds, eg 70-80 km/h and very little throttle the rpm does drop but as noticeable with 100 km/h.

robwijnstok · 21st May 2009, 17:39

Quote:

Originally Posted by RLeon

Hi Rob,

I experience the same with my car, noticeable drop with 100 km/h and backing of throttle. Every year my car has a service with a ex-Rover dealer who has the T4. Never had any fault code reported on the gearbox. I had a read in the workshop manual and in chapter 44 page 36 it is stated that lock-up is possible in gears 2,3,4 and 5. The EAT-ECU regulates this on position of throttle, speed, oil temp(>40 celsius) and to get a smooth lock-up change varies the oil pressure of the lock-up clutch. What I have noticed is that with lower speeds, eg 70-80 km/h and very little throttle the rpm does drop but as noticeable with 100 km/h.

Hi Leon,

So Haynes was correct!!
So I have a "new" feature, just like StevenWilliams... Now it would be nice if I new if it is working or not.

Good that locking is also noticeable working at gear 2, 3, 4 also on your 75.
I never did that on mine. When I drive at work in the morning I have to do 15km on 80km speed roads. I never saw any sign of locking at that speed/rpm’s. I almost never drive with music on (I like the sound of the engine too much

) and I am certain I never could hear the rpm’s drop on that speed also, like it was locking. Perhaps the smooth lock-up is so smooth, that it is working OK all the time and I can’t tell the difference because of that

. Next time I will try to see/hear closer if it is noticeable that it is locking 2, 3 and 4 also. I will ask Juergen if he is taking his T4 on the meeting in Germany next month, perhaps there is an error in the gearbox after all. I recon you will not joining the German meeting as I can’t see you on the list. Must be a day out with the Stag then, and when you do, have lots and lots of fun.

stocktake · 21st May 2009, 17:52

Interesting thread, mine does exactly the same as Stevens, nice to know it is not a fault

James.uk · 21st May 2009, 18:34

Most auto boxes lock up in top gear, but as the lower speeds are rarely held constant for long, the lockups dont get chance to operate.

You may notice lockup on a gentle downhill if you keep your feet off the pedals.

.

20th May 2009, 18:20	#1
robwijnstok Gets stuck in Rover 75 Tourer 2.5V6 autobox, Rover Streetwise 2.0 DTi, MG ZR160 Join Date: Oct 2007 Location: Gelderland Posts: 617 Thanks: 5 Thanked 16 Times in 15 Posts	Haynes glitch on auto box information? Today I was “reading” my Haynes Owners Workshop Manual 2006 edition. On page 7B*2 I read under – 1 General information – that, “to improve economy, the torque converter has a ‘lock-up’ facility in all gears accept for the first, this feature is mentioned for the 75 and ZT. Other automatic gear boxes only have this facility in the top gear”. My boss has a Jaguar X type 2.5V6 with nearly the same mileage and also from 2003 but not half as smooth as my 75, and much much more noisy… but there is in every gear (accept the first) definitely a lockup of the torque converter. After locking, if you are not too hard on the throttle, it stay’s locked. That’s something I would like to have on my 75! I see/hear/feel my gear only locking in fifth gear, a glitch of Haynes? Or am I really missing something? In my auto box that is. Rob. __________________ [SIGPIC][/SIGPIC] Membership Number 344 Driving with a BIG smile... and it's Chatsworth Elegant Bronze. Never drive faster than your guardian angel can fly!

20th May 2009, 20:41	#3
robwijnstok Gets stuck in Rover 75 Tourer 2.5V6 autobox, Rover Streetwise 2.0 DTi, MG ZR160 Join Date: Oct 2007 Location: Gelderland Posts: 617 Thanks: 5 Thanked 16 Times in 15 Posts	Hmm, that is interesting. I recognise that the gearbox fluid has to have a certain temperature before a "lock" is possible, still only in fifth gear that is. When I drive from work on the motorway it does not lock (gearbox cold) when I do 120km/h @ 2500rpm. After a couple of km from work when I exit the motorway roundabout and I gradually increase speed, the gearbox locks immediate when I am in fifth gear just over 102km/h and on that moment I see the rpm’s drop from 2200 to 2100rpm. When I am not hard on the throttle it does not unlock by speed increases, when harder on the throttle it will unlock. And getting harder on the throttle, and kick down will be performed. So this is all Ok. In the other gears I never noticed any drop in rpm’s not with very slow (traffic cue’s etc.), slow or fast acceleration. I think when a torque converter lockup is done at a certain point you must see or hear that at least by some dropping of rpm’s. Mine does that not, so no lockup? Any chance this can be proven by a T4 session by fault code(s)? Rob. __________________ [SIGPIC][/SIGPIC] Membership Number 344 Driving with a BIG smile... and it's Chatsworth Elegant Bronze. Never drive faster than your guardian angel can fly!

20th May 2009, 20:44	#4
jim_mcglynn ZT+ 180 sportsauto MG ZT+ Join Date: Nov 2006 Location: Benfleet Posts: 273 Thanks: 0 Thanked 0 Times in 0 Posts	Sorry for being a thicky, but what does "lock up" mean? __________________ Jim http://www.jimmcglynn.pwp.blueyonder.co.uk/res/gtzt.jpg http://www.jimmcglynn.pwp.blueyonder.../share/bzt.jpg

20th May 2009, 20:57	#5
robwijnstok Gets stuck in Rover 75 Tourer 2.5V6 autobox, Rover Streetwise 2.0 DTi, MG ZR160 Join Date: Oct 2007 Location: Gelderland Posts: 617 Thanks: 5 Thanked 16 Times in 15 Posts	Sorry, that is locking of the torque converter in the auto gearbox. In that way there is no slip between engine and gear anymore. Driving that way is more economic, and the auto gearbox oil temperature will drop also. __________________ [SIGPIC][/SIGPIC] Membership Number 344 Driving with a BIG smile... and it's Chatsworth Elegant Bronze. Never drive faster than your guardian angel can fly! Last edited by robwijnstok; 20th May 2009 at 20:59..

20th May 2009, 21:20	#6
StevenWilliams This is my second home Rover 75 Saloon 2.5 V6 British Racing Green. 81,000 miles and counting Join Date: Apr 2008 Location: Crawley, West Sussex Posts: 6,183 Thanks: 0 Thanked 2 Times in 2 Posts	Thanks. You have answered a question I have been wondering for a while. I thought the behaviour of our cars meant it had an automatic overdrive. Now I understand. When I'm driving and increasing speed after I hit 70 the revs are on about 2400RPM. After about 30 seconds the revs drop to about 2100. I thought it was an overdrive kicking in but it must be the lock kicking in. __________________ [SIGPIC][/SIGPIC] Rover 75 2.5 2000 Club SE. British Racing Green. MEMBER NUMBER: MMMDCCXXVI Looking for: 7 seater

20th May 2009, 18:34	#2
Departed Retired -- Join Date: Jan 2007 Location: -- Posts: 3,785 Thanks: 0 Thanked 4 Times in 4 Posts	Lock up applies to the 75, but not in 1st. It also doesn't happen if the gearbox fluid is cooler than 40C. It's carefully controlled, so you may never know it's locked up. As you say, newer boxes tend to stay in lockup once locked, but older tunes tend to unlock as soon as you apply power, so it sounds like it was never locked.

21st May 2009, 17:52	#9
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,600 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Interesting thread, mine does exactly the same as Stevens, nice to know it is not a fault __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

21st May 2009, 18:34	#10
James.uk Passed Away 2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008 Location: Near the M67. Posts: 14,509 Thanks: 199 Thanked 585 Times in 397 Posts	Most auto boxes lock up in top gear, but as the lower speeds are rarely held constant for long, the lockups dont get chance to operate. You may notice lockup on a gentle downhill if you keep your feet off the pedals. .