Autobox servicing and odd noise identification...

[Vonredbeard]

Hello all, I was wondering if you could give me some pointers on replacing the transmission fluid and filters plus identifying some odd behaviour on my X300 Sovereign please? I'm unfamiliar with the car but want to get the transmission serviced ASAP due to some untoward noises and clunky gearchanges.

The noise is a squeally, sort of chittery racket that in a manual car you'd say was a clutch release bearing on it's way out. It has only happened when in traffic, when hot, in D or N, and goes away as I drive off.

The clunkiness happens when shifting from D to N and so on. Especially bad going into R sometimes. On the road the changes are OK. You do notice them though and I've been told they should be seamless. Kickdown is OK.

There is a major overheating/overcooling issue with the car just now caused by a faulty thermostat and temperature sensors. Could this be causing the problems, or will they be resoved with a simple change of the gearbox fluids?

Many thanks in advance!
Bob

[robv12]

changing the fluid is easy, usual rules on 300 apply, drain the fluid, drop the sump, fit new filter refit sump, refill and run, drain and refill for a second time for a really good change, use bog standard Dex fliud in a 300, it really is that simple unlike the later 308 and 350's, have fun, report back, I would suggest your car will drive better and smoother after this has been done

unlikely a stuck stat will cause any problems to the box, I suggest running the car without a stat if it is overheating until you can pop a new one in, cheap and easy to do, 10 minute job at max

the chatter could be a catalyst heat shield, these corrode and become loose, but as always with these things difficult to diagnose from afar with out the car here

[Vonredbeard]

Thanks Rob, I'll give it a bash. One of the good things about being at college is access to the workshops and a willing class full of helpers keen to get their mitts on the Jag. It just so happens we're doing cooling systems this month so a thermostat job ties in nicely!

[Vonredbeard]

I'm ready to tackle this job now after the easter break thanks to the correct bits being ordered through Mulsanne Motors.

As I understand it the transmission level needs to be checked while the engine is running and the car is in neutral, but where is the correct level on the dipstick? Also, while the total capacity of the system is 10 litres, only 5 or so will be able to be replaced at a time, is that right?

While the car is on a ramp I'm doing the diff too. Is it just EP90 that's used here and a simple case of re-filling the housing until it runs out the filling hole?

Sorry for all the 'newbie' questions, but I just want to make sure that I do a proper job and add value to the car.

PS. Touch wood - the overheating problem seems to have been fixed with the new fans. Thanks Rob!

[robv12]

trans oil level should be checked when hot, there is a "hot " mark one side of the dip stick, and a "cold" mark on the other side, slightly lower down, you will never get a complete change of fluid and you will have old fluid in the cooler and torque converter, some suggest changing the fluid twice to purge as much of the old stuff as possible

with the diff, ensure you can get the fill plug out BEFORE you drain the oil out, refill with Shell Super Spirax 90 oil, the spec of this is A.P.I GL5

[Vonredbeard]

I'm happy to report that the transmission fluid and filter change was a total success. Judging by the state of the fluid drained out, which smelled terrible and was the colour of black coffee, plus the fact that both sump magnets were coated with grey slime, I reckon that today was probably the first time the £600 Sov has had a transmission service!

Gearchanges are much, much smoother and the car feels livelier, snappier and quicker off the mark. Certainly isn't as slushy as it was.

Good times!

[robv12]

a good job well done, see you in Reston soon them for more parts!!