Upshift 3 to 4 on V8 auto

75SCO · 11th January 2012, 11:02

Folks, want to find out if this is something more worrying or another one of those quirks of our well-engineered cars

:

My V8 autobox does what it is supposed to do, it whines in first gears just like all the other ones appear to do, but I noticed that upshifts from 3 to 4 sound and feel "longer", there is more of a slur before 4th appears to be engaged. Kickdown works as it should, all other functions work, so does manually downshifting to 2nd. It is just this delay in engaging 4th that makes me wonder. Anyone else experienced something like this?

Axel

J1MBO · 11th January 2012, 12:47

It's a three speed auto, what you're feeling is the lock up of the transmission.

kaiser · 11th January 2012, 13:40

Quote:

Originally Posted by J1MBO

It's a three speed auto, what you're feeling is the lock up of the transmission.

I don't think that is correct. It is a 4R70W automatic box, as far as I can ascertain, and it is described as a four speed unit, with fourth gear being an overdrive.
My box also whines in first, I guess that is just a feature of the box.
However, what I have found out, is that sometimes mine hesitates, and hunts if it is supposed to change up into 4th.
I believe it has something to do with selection of "drive". Next time it happens, try and switch the gear lever into N and back into D.
You can also switch traction control off, it seems to cause some weird reactions at times.

J1MBO · 11th January 2012, 14:46

Now that does surprise me, I wrongly understood it to be a 3 speed and just thought that the later slight drop in revs was due to the torque converter "locking up" whilst cruising.

In my mind it doesn't like changing up, really needing the right foot lifted to do so, and at speeds around 30mph still seems to be in second in my case.

Well you live and learn.

kaiser · 11th January 2012, 15:14

The box on the smaller Rovers have a lock-up function, which effectively mechanically couples the input and output shafts, eliminating the losses in the torque converter in top gear.
When that engages, you get a drop of a few hundred rpm as the shafts lock solidly. That feels like an extra gear, but is just the torque converter slip taken up.
I am not even sure if our boxes have such a function. I seem to remember having read they do, but I am not sure I have ever noticed it engage.
Must try and find out.

J1MBO · 11th January 2012, 16:05

Had to pop out to collect the good lady from work, hence the rather abrupt previous post.

I'd checked on wiki regarding the transmission and it makes interesting reading

http://en.wikipedia.org/wiki/Ford_AOD_transmission

so I guess the scenario in my case is what I was perceiving as a 2nd to 3rd upshift must be a 3rd to 4th upshift. This would seem to be confirmed by the description in the above with regards to the closeness of the ratio's of the first two gears.

Answering the op's original question, it would now seem to be, as the 4th gear ratios is so high it'd need some speed before 4th would/could be engaged. In fact at 70mph my car's engine is at about 2000-2100rpm.

Interesting, you learn something everyday.

EDIT: I find it a very smooth transmission under normal throttle openings hence why I may well have not been noticing the change from 1 to 2, even when using a heavy right foot it's smooth and it could well be changing up 2 gears when I lift off.

DerekS · 11th January 2012, 16:46

The automatic transmission features a five speed gearbox with
three manually selectable modes (Normal (economy), Sport
and Snow mode).

Extracted from the manual .

(mines not auto )

wutang · 11th January 2012, 16:52

Quote:

Originally Posted by DerekS

The automatic transmission features a five speed gearbox with
three manually selectable modes (Normal (economy), Sport
and Snow mode).

Extracted from the manual .

(mines not auto )

Not on the 4.6 V8 which is what is being discussed it gets the 4 speed box with 4th being an overdrive gear, 5 speed on all other varieties.

Richard

philby777 · 11th January 2012, 20:24

When warm mine changes into the overdrive (4th at around 36 mph) When cold first thing in the morning it takes awhile for the overdrive to kick in about a mile and 45 to 55mph when it comes in . No whine in mine in first all gears are quite and smooth.
This box has the ability to lock out the overdrive which along with being able to select second gear would give you a bit of fun on a track day.

This feature is on the mustang where they had 3 close gears and a big jump for 4th for highway driving, ( where as the rover gears are better spaced )

The lock out feature was used for when you floored the car for 1/4 mile the gearbox could not take the jump in gearing from 3rd to the higher 4th at 6 to 7000rpm so they had switch on the knob and a light on the dash telling them the overdrive was locked out
I am trying to get an auto spark who can identify the wires on the gearbox which lock out the overdrive if anyone could help that would be great.
Phil

DerekS · 11th January 2012, 22:28

"Quote:
Originally Posted by DerekS
The automatic transmission features a five speed gearbox with
three manually selectable modes (Normal (economy), Sport
and Snow mode).

Extracted from the manual .

(mines not auto ) "

Not on the 4.6 V8 which is what is being discussed it gets the 4 speed box with 4th being an overdrive gear, 5 speed on all other varieties.

Richard

Whoops ! I get annoyed at posters who dont read the full thread, and then answer the wrong question. Got caught out myself this time ! Sorry .

11th January 2012, 11:02	#1
75SCO Regular poster Jaguar X-Type Estate Join Date: Nov 2011 Location: Scottish Highlands Posts: 97 Thanks: 0 Thanked 1 Time in 1 Post	Upshift 3 to 4 on V8 auto Folks, want to find out if this is something more worrying or another one of those quirks of our well-engineered cars : My V8 autobox does what it is supposed to do, it whines in first gears just like all the other ones appear to do, but I noticed that upshifts from 3 to 4 sound and feel "longer", there is more of a slur before 4th appears to be engaged. Kickdown works as it should, all other functions work, so does manually downshifting to 2nd. It is just this delay in engaging 4th that makes me wonder. Anyone else experienced something like this? Axel __________________ Six-thirty-one sold

11th January 2012, 16:05	#6
J1MBO This is my second home Roverless & now carless Join Date: Dec 2008 Location: Wilmslow Posts: 15,583 Thanks: 2,457 Thanked 2,428 Times in 1,301 Posts	Had to pop out to collect the good lady from work, hence the rather abrupt previous post. I'd checked on wiki regarding the transmission and it makes interesting reading http://en.wikipedia.org/wiki/Ford_AOD_transmission so I guess the scenario in my case is what I was perceiving as a 2nd to 3rd upshift must be a 3rd to 4th upshift. This would seem to be confirmed by the description in the above with regards to the closeness of the ratio's of the first two gears. Answering the op's original question, it would now seem to be, as the 4th gear ratios is so high it'd need some speed before 4th would/could be engaged. In fact at 70mph my car's engine is at about 2000-2100rpm. Interesting, you learn something everyday. EDIT: I find it a very smooth transmission under normal throttle openings hence why I may well have not been noticing the change from 1 to 2, even when using a heavy right foot it's smooth and it could well be changing up 2 gears when I lift off. Last edited by J1MBO; 11th January 2012 at 17:07.. Reason: thoughts........

11th January 2012, 20:24	#9
philby777 Regular poster R75V8 development car Join Date: Dec 2006 Location: Co Down Posts: 47 Thanks: 0 Thanked 0 Times in 0 Posts	Auto When warm mine changes into the overdrive (4th at around 36 mph) When cold first thing in the morning it takes awhile for the overdrive to kick in about a mile and 45 to 55mph when it comes in . No whine in mine in first all gears are quite and smooth. This box has the ability to lock out the overdrive which along with being able to select second gear would give you a bit of fun on a track day. This feature is on the mustang where they had 3 close gears and a big jump for 4th for highway driving, ( where as the rover gears are better spaced ) The lock out feature was used for when you floored the car for 1/4 mile the gearbox could not take the jump in gearing from 3rd to the higher 4th at 6 to 7000rpm so they had switch on the knob and a light on the dash telling them the overdrive was locked out I am trying to get an auto spark who can identify the wires on the gearbox which lock out the overdrive if anyone could help that would be great. Phil

11th January 2012, 12:47	#2
J1MBO This is my second home Roverless & now carless Join Date: Dec 2008 Location: Wilmslow Posts: 15,583 Thanks: 2,457 Thanked 2,428 Times in 1,301 Posts	It's a three speed auto, what you're feeling is the lock up of the transmission.

11th January 2012, 14:46	#4
J1MBO This is my second home Roverless & now carless Join Date: Dec 2008 Location: Wilmslow Posts: 15,583 Thanks: 2,457 Thanked 2,428 Times in 1,301 Posts	Now that does surprise me, I wrongly understood it to be a 3 speed and just thought that the later slight drop in revs was due to the torque converter "locking up" whilst cruising. In my mind it doesn't like changing up, really needing the right foot lifted to do so, and at speeds around 30mph still seems to be in second in my case. Well you live and learn.

11th January 2012, 15:14	#5
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	The box on the smaller Rovers have a lock-up function, which effectively mechanically couples the input and output shafts, eliminating the losses in the torque converter in top gear. When that engages, you get a drop of a few hundred rpm as the shafts lock solidly. That feels like an extra gear, but is just the torque converter slip taken up. I am not even sure if our boxes have such a function. I seem to remember having read they do, but I am not sure I have ever noticed it engage. Must try and find out.

11th January 2012, 16:46	#7
DerekS Posted a thing or two Rover 75 Tourer Join Date: Nov 2006 Location: Malpas Posts: 1,526 Thanks: 34 Thanked 118 Times in 89 Posts	The automatic transmission features a five speed gearbox with three manually selectable modes (Normal (economy), Sport and Snow mode). Extracted from the manual . (mines not auto )

11th January 2012, 22:28	#10
DerekS Posted a thing or two Rover 75 Tourer Join Date: Nov 2006 Location: Malpas Posts: 1,526 Thanks: 34 Thanked 118 Times in 89 Posts	"Quote: Originally Posted by DerekS The automatic transmission features a five speed gearbox with three manually selectable modes (Normal (economy), Sport and Snow mode). Extracted from the manual . (mines not auto ) " Not on the 4.6 V8 which is what is being discussed it gets the 4 speed box with 4th being an overdrive gear, 5 speed on all other varieties. Richard Whoops ! I get annoyed at posters who dont read the full thread, and then answer the wrong question. Got caught out myself this time ! Sorry .