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Rover 75 2.0 V6 Automatic - 2000 - Gearbox problems ?

11K views 10 replies 4 participants last post by  cdato 
#1 ·
Hi,

My Rover 75 KV6 2,0 2000 with the jacto-gearbox is a truly wonderful car. But recently (the last year or so) the gearbox has started to change gears really, really hard. It only happens when the engine (gearbox) is cold and only on the first 5-10 changes.

About half a year ago I changed gearbox oil (Transmax Z). The problem then disappeared for a month or so.

Anyone got any thought about what the problem could be?

/Rickard
 
#2 ·
Auto Box



Hi Rickard. Of interest what mileage now ?
I think Transmax is a Castrol Fluid. I contacted Castrol directly. In short they said that "they do not produce a fluid suitable for the Jatco Box"
At the time there was considerable discussion here about fluids and it was positively stated that no other fluid contains the additives required in a Jatco box. Only Texaco N402 (Rover part No. VYK 00040/ L/Rover No. LNR402) is suitable. I think it was stated that the Jatco box operates very hot. It also does not have a filter.
Whether this is the reason for your problem I don't know.
Worryingly, Ashcroft Transmissions, who are reputable recon. Co told me that they recommended Transmax for Jatco boxes ! ! !
 
#3 ·
not transmax Z

If you are going to use a castrol oil it needs to be transmax J not "Z"

I am also having harsh change problems..but when hot....I changed the oil over last week to the lrn-402 ($200AUD) for 5 litre. Didn't fix the problem at all.

I have been doing some research via the freelander site (since it uses the same jatco box) and have read that the problem can be 1. speed senor or transmission oil temp sensor..

cheers

coolrain
 
#4 · (Edited)
N402

If you are going to use a castrol oil it needs to be transmax J not "Z"

I am also having harsh change problems..but when hot....I changed the oil over last week to the lrn-402 ($200AUD) for 5 litre. Didn't fix the problem at all.

I have been doing some research via the freelander site (since it uses the same jatco box) and have read that the problem can be 1. speed senor or transmission oil temp sensor..

cheers

coolrain
That sounds like a rip off. I originally heard that it was very expensive but then got the price of £24.33/ 5litres (incl. tax) and that is from Xpart who know how to charge 'top dollar'. Don't think that is expensive for a low volume seller. I think it was an Australian member who had looked into it and spelt out the additional additives in N402 necessary for the Jatco box.
Castrol themselves said they do not sell a fluid suitable for the Jatco box and that includes Transmax Z & J
Thats interesting about the speed sensor or oil temp sensor. Wonder how much to replace those if they are replaceable without box removal. If not too expensive could be worth replacing those before looking for internal problems /overhaul/replacement
 
#5 ·
high line pressure

With the castrol oil..you can visit their site and look under small 4 wheel drive then "freelander" it states there to use transmax J

Anyway, in regards to harsh gear changes, I have finally got my hands on a maintenance cd for the rover...so I browsed the jatco auto section.

In there it states " the ECU calculates line pressure" Blah blah blah..

High line pressure will cause very harsh gear changes and engagements (my problem) low line pressure will cause gear shifts to take excessive time.

looked at the other prblems (sensors) but they point to problems like not engaging 5th gear which isn't my problem.

One could deduct from your problem that line pressure isn't being caculated properly while the engine is still cold..

cheers

coolrain
 
#6 ·
INTERMEDIATE speed sensor

For those who may have the same problem with harsh gear changes..I had the car diagnosed by a lndrover specialist today and the fault is a dead intermediate speed sensor. after clearing the fault we took the car for a drive whilst we had the testbook running and it showed not output from the sensor.

Luckily, I believe this sensor is on the outside of the gearbox just below where you fill the transmission with oil and behind the oil cooler
 
#7 ·
Speed sensor

For those who may have the same problem with harsh gear changes..I had the car diagnosed by a lndrover specialist today and the fault is a dead intermediate speed sensor. after clearing the fault we took the car for a drive whilst we had the testbook running and it showed not output from the sensor.

Luckily, I believe this sensor is on the outside of the gearbox just below where you fill the transmission with oil and behind the oil cooler
Thanks for that. Perhaps we are getting closer to finding a solution for some auto box problems without replacing the whole box. Makes one wonder if auto transmision repairers know this but laugh up their sleeve when recommending box replacement. They can probably fix some faults for a few £'s.
PLEASE let us know how you get on and cost of replacing sensor, if that is possible. (and if spares are obtainable)
One thing I can tell you about my contact with Jatco themselves. We don't answer queries, contact the vehicle manufacturer. I sent a reply asking if they knew one of their customers, ROVER, didn't exist anymore. (I was only trying to get confirmation of suitable fluids !)
I could not find a UK address for Jatco or an agent. Maybe a reason 'Honest John' said in an article that spares for Jatco boxes were 'impossible'
 
#8 ·
iss

You are correct with the specialist..when I took it to one (transmission) we took the car for a drive..he blurped about all the possible problems. I said that my local garage changed the sensor on the outside of the gearbox, I think it was the speed sensor!.

He replied, no must have been the intermediate speed sensor. The speed sensors are in the box..

Ah, I replied..

He sent me to this landrover specialist who had autologic..which is where I went and had the car tested. The landy guy was apprehensive as he had never tested a rover before...Anyway told him to set the car to freelander and out spat the data..look, it doesn't check everything but it could get info from the jatco transmission.

Anyway, headed back to the trany specialist and told him the problem of the iss (intermediate speed sensor) He replied oh, thats going to cost around $3000AUD, the whole box is having to come out.


Anyway my brain just went &&^%$ as I distinctly heard him tell me the intermediate sensor was the one I had replaced .. (20 min job once you get the part)


I rang up my local guy and told him the problem.. he said no worries will replace the part..

hope to have it done within the week
 
#9 ·
This seems to be an appropriate thread to ask a question about a very similar problem I currently have.

I recently had a new ECU fitted on my W-reg Rover 75 1.8 Club SE Auto (118,000 mls). Since then, the gear changes have been harsh, when they were almost unnoticeable before.

The garage (F.J. Keen in Battersea Park Road, London) diagnosed a badly worn engine mounting as part of the problem. Although replacing the mounting resulted in a slight improvement, Keen said the main fault may be a mechanical one internal to the gearbox.

My first thought was that the harsh gear changes may be connected to the installation of the new ECU, as I did not have this problem before, but the mechanics at Keen said that the ECU they replaced had nothing to do with the gearbox, which is controlled by the gearbox interface unit (GIU) and worked exactly as it should. I cannot disprove this, but it strikes me as an extraordinary coincidence that an unconnected problem should appear at exactly this moment.

Admittedly, the car has not been fully services in the three years I have owned it, so I wanted to ask the experts here:

a) Any suggestions as to probable causes for the harsh gear changes?

b) Would a change of gearbox fluid (perhaps as part of a full service) remedy the fault?

Your help would be greatly appreciated.

Thanks,
Chris
 
#10 ·
cheapest way is get a diag done (t4)

I still have problems with my grear box..to many different opinions to be confident I am not being ripped off..

Firstly, find a service guy that has a t4 system that can check the ecu and gearbox..mybe all that is needed is a fault code reset..


If the car goes in for service and the transmission is smooth it should be the same when it comes out..and since the ecu was the itme replaced then its a pretty sure bet that is causing the problem..

Its probably sending incorrect info to the gearbox by maintaining high pressure which then causes the harsh changes
 
#11 ·
Thank you for your reply, coolrain, which mirrors my thinking. However, the garage, which has a T4 system, insists that the ECU is set up correctly and that they can't find any other faults. So, unless I find a specialist who proves otherwise, I have no leverage.

Can anyone here recommend a competent repair or service centre with expertise in ECU calibration and transmission set-up?

Thanks,
Chris
 
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