|
||
|
16th August 2018, 17:22 | #1 |
Loves to post
Rover 75 Tourer Join Date: Sep 2011
Location: Leeds
Posts: 494
Thanks: 68
Thanked 76 Times in 43 Posts
|
Normal Jatco behaviour?
Not really a cry for help but for opinions. I've had my Rover 75 2.5 KV6 (174 ps) automatic tourer for almost four years and apart from the abysmal fuel consumption, I've been very happy with it. While driving through Germany, I've been able to 'let her go a bit' and achieved speeds that I would never dare attempt in the UK. But one thing it's highlighted is the (on my car) annoying behaviour of the autobox seeming to change up from 5th to a mysterious '6th' gear while accelerating in 5th and holding the car back unless I blip and hold the throttle down to counteract it (it usually drops down into 4th). I think this 6th gear is actually the direct drive mechanism cutting in; it has the effect of dropping the revs a bit and I can feel the car holding back in 5th. Normally, this doesn't bother me, but on the autobahn, there's nothing worse than accelerating to overtake someone and finding the gearbox holding you back (unless I kick-down to or manually select 4th). Even then, it has the equally annoying habit of changing up too quickly (unless I keep in in 4th). My guess is that this is all completely normal behaviour that I've got used to on our slower roads, but I just wanted to confirm it.
|
16th August 2018, 17:51 | #2 |
Vis Whiz
Rover 75 2.5 auto Saloon Join Date: Jun 2007
Location: LEEDS
Posts: 20,582
Thanks: 2,057
Thanked 3,056 Times in 1,621 Posts
|
Sounds like you are experiencing the lock up of the torque converter, mine does it around 65 -70 mph. perfectly normal
__________________
Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident |
16th August 2018, 17:52 | #3 |
Posted a thing or two
MG ZT Join Date: Jul 2014
Location: Hornchurch
Posts: 1,255
Thanks: 176
Thanked 352 Times in 272 Posts
|
In these moments when you've got the 'need for speed', use Sports mode. It will change up at around 2200 rpm normally, hold onto fourth until 65 ish and generally kick down eagerly. Even in top gear.
All these figures from a dizzle auto. Yours may be a bit different. I find the D mode quite frustrating as it is hell bent on changing up at the earliest opportunity, but have learnt to live with it (it is economy mode after all) and use Sports mode when I want better response and as you said use D3 and D4 when I want to be in total control. |
17th August 2018, 07:04 | #4 |
Loves to post
Rover 75 Join Date: Jul 2015
Location: Tamworth
Posts: 291
Thanks: 2
Thanked 72 Times in 65 Posts
|
Torque converter lock up, there to mechanically lock the box to the engine and save losses in the fluid link between them.
Pretty normal and always felt a bit slow at disengaging to me but hey ho. |
17th August 2018, 07:46 | #5 | |
Loves to post
Rover 75 Tourer Join Date: Sep 2011
Location: Leeds
Posts: 494
Thanks: 68
Thanked 76 Times in 43 Posts
|
Quote:
The KV6 auto definitely needs to change down more often for a decent burst of acceleration, including getting the VIZ motors working at their best. It's just that in economy 'D' mode, it does like to change up too quickly again! |
|
17th August 2018, 19:24 | #6 |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
David,
Have you checked that the pinhole restriction in your cam covers is clear lately? Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
18th August 2018, 07:37 | #7 |
Loves to post
Rover 75 Tourer Join Date: Sep 2011
Location: Leeds
Posts: 494
Thanks: 68
Thanked 76 Times in 43 Posts
|
|
Thread Tools | |
Display Modes | |
|
|