Auto gearbox problems help required

[lifeboatandy]

I have had my 3.2 x300 layed up in the garage for a few weeks whilst I replaced the headlining and changed the windscreen for a heated windscreen. Which I had to find and then install the extra wiring for the heated windscreen upgrade.
Whilst I was moving it about the garage the air conditioing compressor clutch also decided to fail and was replaced from a scrapper.
Once back on the road the auto box is now very rough on the gear changes and seems to hold on to the gears, not wanting to change up. I can encourage to change up by easing off the power which seems to make it change. It also seems to want to kick down the gears as I slow down. The car has only covered 60, 000miles and I have recently changed the gearbox Fliud
Anybody got any ideas what's gone wrong .???

[ptjs1]

lifeboat andy,

Did you change the gearbox filter in the sump when you changed the fluid? Also, how did you change the fluid - from sump plug or via dipstick extraction etc?

Paul

[lifeboatandy]

Hi Paul
I used the sump plug method, drained and refilled 3 times and on the last changed the filter. She has always had a clonking reverse but now all of a sudden she has very rough clonking gear change.stange it has suddenly happened after a few weeks lay up.
Everybody states the gearboxes are bullet proof !

[ptjs1]

lifeboat andy,

The boxes really do have a good reputation and even if the previous owner had neglected maintenance and not previously changed the oil and filter, 60k isn't usually the end of the world. However, with your layup and old fluid, the transmission or torque converter may have got a bit "sticky".

The key element as you've probably realised, you can only extract less than 30% of the fluid when draining from the sump plug (or dispstick extraction). I have recently been doing a change on the similar 4HP24 box in my XJS. I can only extract approx 2.45 litres each time. But the oil system has a total capacity of 9 litres with a significant element sitting in the torque converter and transmission oil cooler etc. As you dilute back the old oil each time you do a change you really need quite a few changes to really get it clean. I have done four flushes this week with 10 mile runs in-between each change. I'll do 2 more changes, then change the filter, then do 4 changes. I know it's a lot of fluid and hassle but fluid is cheap really and it is necessary in order to get it fully changed with clean fluid.

The other way that it can be done is to undo the return pipe from the cooler at the transmission end, start the engine, cycle the box and, as the old fluid is pumped out into a suitable receptacle, have someone refill the same amount into the dipstick tube. It's a bit fiddly, needs two people, but you can do it then with about 10-12 litres that way.

In fairness, you've gone further than most people even by doing 3 changes, but you'll still have an amount of old fluid in there.

For the sake of 10 litres of fluid (Dexron III, rather than Dexron II), you might choose to try a few more flushes.

Good luck

Paul

[PeterDavisX300]

A real shot in the dark here. I wonder if it might be an idea to clean the MAF sensor? I have a couple of older cars, one of which is a Ford-Scorpio, (NOT a Granada) The MAF sends certain messages to control units that read engine speeds, and in turn send messages to the gearbox. What I do know is, a Scorpio Ultima Cosworth with a dirty MAF sensor has terrible clunky gearbox changes. To clean the sensor, just get a good can of spray carb-cleaner, (smells like thinners with a powerful spray, about £7) Take the MAF off and spray directly onto the thin wires in the sensor block. DON'T be tempted to try and touch with a rag or anything to clean the very thin sensor wires, you'll break them! There are a lot of common items with FORD on these X300's, I've just done a repair to a spare ABS control unit for my X300, it's the same as the Scorpio's, and gives the same intermittent fault-code reading 1095, which means it needs an easy soldering repair. Just a thought. Hope it helps.

[naki]

Have you doubled checked the fluid is filled to the correct level?

Parked On level ground. Cold idle in neutral, but run through D and R a few times first. Overfilling fluid can cause problems.