Brucie’s Diary: June 2012

Current mileage: 141,078


X300 Transmission Fluid Change – Third Time Lucky!

“There is a problem with most automatic transmissions in that whilst there is means of draining the gearbox it is impossible to drain the oil from the torque convertor so at best any oil change will be a partial improvement unless followed up with a further oil change. So wrote Rod Doone in Sealed for life – or not? which appeared in the January 2012 issue of Xclusively Jaguar News.

Well, I think we can say after 3 transmission fluid changes in less than a year, Brucie’s gearbox must be just as clean as we are ever likely to get it!

The first transmission fluid change was merely, as far as I was concerned, part of an overdue service. I had noticed some oil leaking from the gearbox, but had put this down to a failed seal, and had assumed that this was just perished due to being left longer than desired. This and the second transmission fluid change are both detailed below, which explains the reason for the third transmission fluid change.


June 2011 – First transmission fluid change
A change of transmission fluid was high on my list of priorities, and Brucie decided to hurry me along with this by making regular deposits of oil on the garage floor, which was obviously from the vicinity of the gearbox. I purchased the appropriate parts (O-ring, filter and sump gasket) from SNG Barratt, however, I didn’t specify genuine Jaguar parts as I have had no complaints about the quality of non-genuine items purchased from them in the past, and there is a marked difference in the price of genuine and non-genuine parts! The transmission fluid change was performed by a local non-Jaguar garage who I have used before and have great faith in.


August 2011 – second transmission fluid change
While Brucie was up on the ramp having a new set of front wheel bearings fitted, it became apparent that the oil leak from the gearbox had not been cured. This could have been for several reasons – 1. An electrical plug which fits into the gearbox was not quite snug. 2. The price of the sump gasket suggested that it was not genuine Jaguar and these have been known to be less pliable and therefore not fit properly. 3. The bolts may have been over-tightened, pinching the gasket and rendering it useless. I was unconcerned by the cause, so long as it could be remedied. I ordered a new sump gasket, this time from Jaguar Classic Parts, so that I could be sure that it was a genuine Jaguar part – the price of this “genuine part” was a bit of a shock, so I hoped that all would go well and it would be worth it! A date was fixed for a second transmission fluid change, and in view of the fact that this gearbox may have missed a scheduled oil change, I was not too fussed, as the exercise meant that it had been flushed through and this time, hopefully, all would be well. The mechanic noted that the electrical plug was loose, so it may prove that this is the problem, if the oil leak is not cured this time. The recently replaced filter was flushed through, before replacing it with the new oil and fitting up the new gasket, so Brucie should be good for another 2 years before his next scheduled transmission fluid change – and next time it won’t be missed out!


March 2012 – third transmission fluid change
Needless to say, the second service didn’t cure the problem, so we therefore had to assume that it was the ill-fitting electrical connector which was leaking, and this meant dropping the gearbox to access the electrical connector with a further full gearbox service to follow!

Listed below are the parts which were required to rectify the leak from the gearbox, and which provided a further change of transmission fluid as a bonus!


Part Part Number Price
Harness JLM 12337 £78.20 (+ VAT)
Sump Gasket JLM 12343 £17.11 (+ VAT)
Transmission Fluid Filter JLM 2128 £29.67 (+ VAT)
O Ring/Seal JLM 2127 £0.32 (+ VAT)
O Ring JLM 10473 £1.33 (+ VAT)
Transmission Fluid (5 litres)* C2P 10360 £26.94 (+ VAT)


*Dextron Type 2 Transmission Oil It was explained to me that where this is specified, it has been superseded by successive numbers 3, 4 etc. This means that the oil meets a superior standard to the original oil specified and is safe to use in all applications where the lower number is specified.

All parts supplied by Jaguar Classic Parts and SNG Barratt (prices correct at time of publishing).