Auto box fault

debo · 2nd March 2015, 08:08

hi all my 2002 cdt auto is playing up. It has an intermittent fault which it has had since I got it over a year ago and only does it now and again more often when the engine is hot. when accelerating it will go all through the box fine then On changing into 5th it sometimes loses drive like its in neutral let your foot of the gas then back on again and it engages fine. does anybody have any clue about what might be happening.any help would be much appreciated thanks

SD1too · 2nd March 2015, 08:40

Hello Shaun,

You may have a faulty solenoid valve. These can be checked using a multimeter on a multipin electrical connector which is fairly easily accessible. This has been dealt with before so a forum search should reveal all.

The other possibility is that the fluid needs changing, or has been changed and the wrong specification used, or the level is incorrect.

Simon

Busboy · 2nd March 2015, 08:43

Hi Debo.

From the symptoms that you describe I have had a think about it and my CDTi Auto does something similar, I put it down to a sort of economy freewheeling function that senses road speed and engine load, my car suffers no ill effects and I assume that it supposed to be like that, I expect you will receive a reply shortly from somebody who is better versed to give a full technical explanation. I would be interested to find out too! - kind regards -Keith.

SD1too · 2nd March 2015, 09:34

Keith, I think what you are describing and what Shaun is describing are two different things. Here's MG Rover's explanation of what I think you are talking about.

Simon

debo · 2nd March 2015, 12:25

thanks for the replys i have just checked the solinoids and here are the results
shift solinoid a 16.3
shift solinoid b 16.2
shift solinoid c 16.3
low clutch timing 16.2
2/4 timing 16.6
reduction timing 16.2
presure control 02.9
2/4 duty 02.9
tcc 12.6

i think they are all in spec the only two which look suspect are presure control and 2/4 duty which have come up with a 0 in front of the numbers if you remove the 0 they are also in spec i dont know if this is right as its the first time ive used one of these meters and its set to auto hope somebody can shed some light thanks

Alan123 · 2nd March 2015, 15:01

2/4 soliniod is always favourite to go your reading does seem a bit low
Have a look in the how too under jatco auto box.

debo · 2nd March 2015, 20:51

Does anyone know if you can test the reverse piston anyhow with out taking it out of the gearbox

RPWC · 2nd March 2015, 21:14

Quote:

Originally Posted by debo

Does anyone know if you can test the reverse piston anyhow with out taking it out of the gearbox

Yes you can I don't know how to do it, but it can be tested and replaced with the gearbox in situ. If you search for reverse piste auto box, you will likely find the relevant info.

rrobson · 2nd March 2015, 21:24

Yes, you can test the reverse piston. You need a pressure tester. I have one but I'm not going to be home for a number of weeks so wouldn't be able to get it to you.

With 5th dropping out it could be explained by the reverse piston but it would have taken fully hold by now if it was that. There are plenty of potential explanations but nothing that's common.

debo · 3rd March 2015, 06:05

Ok thanks how big of a job is it to change the complete box then I have access to a two post ramp and tools

2nd March 2015, 08:08	#1
debo Regular poster rover 75 saloon Join Date: Nov 2013 Location: great yarmouth Posts: 74 Thanks: 13 Thanked 3 Times in 3 Posts	Auto box fault hi all my 2002 cdt auto is playing up. It has an intermittent fault which it has had since I got it over a year ago and only does it now and again more often when the engine is hot. when accelerating it will go all through the box fine then On changing into 5th it sometimes loses drive like its in neutral let your foot of the gas then back on again and it engages fine. does anybody have any clue about what might be happening.any help would be much appreciated thanks

2nd March 2015, 08:40	#2
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,531 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Hello Shaun, You may have a faulty solenoid valve. These can be checked using a multimeter on a multipin electrical connector which is fairly easily accessible. This has been dealt with before so a forum search should reveal all. The other possibility is that the fluid needs changing, or has been changed and the wrong specification used, or the level is incorrect. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

2nd March 2015, 09:34	#4
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,531 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Keith, I think what you are describing and what Shaun is describing are two different things. Here's MG Rover's explanation of what I think you are talking about. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

2nd March 2015, 21:24	#9
rrobson I really should get out more....... 75 tourer cdti, MG ZS 180, nissan terrano & 1.8t rover 25 Join Date: Feb 2010 Location: Pontefract Posts: 2,647 Thanks: 17 Thanked 295 Times in 218 Posts	Yes, you can test the reverse piston. You need a pressure tester. I have one but I'm not going to be home for a number of weeks so wouldn't be able to get it to you. With 5th dropping out it could be explained by the reverse piston but it would have taken fully hold by now if it was that. There are plenty of potential explanations but nothing that's common. __________________ How to view a car - everything you need to help you inspect a used car VIS motor tester avalible to local members Injector removal tool and auto gearbox pressure tester now available

2nd March 2015, 08:43	#3
Busboy Loves to post 75 tourer (facelift) 2.0 CDTi Join Date: Sep 2014 Location: Gravesend Posts: 482 Thanks: 456 Thanked 55 Times in 39 Posts	Hi Debo. From the symptoms that you describe I have had a think about it and my CDTi Auto does something similar, I put it down to a sort of economy freewheeling function that senses road speed and engine load, my car suffers no ill effects and I assume that it supposed to be like that, I expect you will receive a reply shortly from somebody who is better versed to give a full technical explanation. I would be interested to find out too! - kind regards -Keith.

2nd March 2015, 12:25	#5
debo Regular poster rover 75 saloon Join Date: Nov 2013 Location: great yarmouth Posts: 74 Thanks: 13 Thanked 3 Times in 3 Posts	thanks for the replys i have just checked the solinoids and here are the results shift solinoid a 16.3 shift solinoid b 16.2 shift solinoid c 16.3 low clutch timing 16.2 2/4 timing 16.6 reduction timing 16.2 presure control 02.9 2/4 duty 02.9 tcc 12.6 i think they are all in spec the only two which look suspect are presure control and 2/4 duty which have come up with a 0 in front of the numbers if you remove the 0 they are also in spec i dont know if this is right as its the first time ive used one of these meters and its set to auto hope somebody can shed some light thanks

2nd March 2015, 15:01	#6
Alan123 Posted a thing or two Rover 75 saloon Join Date: Oct 2013 Location: Darlaston Posts: 1,897 Thanks: 484 Thanked 325 Times in 261 Posts	2/4 soliniod is always favourite to go your reading does seem a bit low Have a look in the how too under jatco auto box.

2nd March 2015, 20:51	#7
debo Regular poster rover 75 saloon Join Date: Nov 2013 Location: great yarmouth Posts: 74 Thanks: 13 Thanked 3 Times in 3 Posts	Does anyone know if you can test the reverse piston anyhow with out taking it out of the gearbox

3rd March 2015, 06:05	#10
debo Regular poster rover 75 saloon Join Date: Nov 2013 Location: great yarmouth Posts: 74 Thanks: 13 Thanked 3 Times in 3 Posts	Ok thanks how big of a job is it to change the complete box then I have access to a two post ramp and tools