auto gearbox
- Thread starter hamrag
- Start date
tr7v8
New member
It could be fluid level. Is the box quiet, no whining noises or screeching. The seals go hard at high mileage & or old age & the line pressure will drop so the pump has to work harder get enough pressure up to engage the bands & clutches. This is why it's OK once warm & on the move.
Or the wrong type of fluid. I think as others have suggested the place to start is a fluid change to the correct level with the right type of ATF. Possibly fill and flush once or twice so you get more of what's in the torque convertor out, assuming the 944 auto won't drain completely simialr to the Jeep one I'm dealing with now.
I didn't get a chance to do mine yesterday as I had hoped, but my plan is to drain it then fill and then select all the gears in turn to open all the valves before draining again and decide based on the colour of the fluid if that is enough. Fortunately my fluid looks pretty clean and pink at the moment, but it could take a lot of goes if the current stuff is murky.
Another option is to get it flushed so you get all the old fluid out, but I've heard enough tales of that making things worse on older autos that I'm not sure I'd have it done it to mine.
I didn't get a chance to do mine yesterday as I had hoped, but my plan is to drain it then fill and then select all the gears in turn to open all the valves before draining again and decide based on the colour of the fluid if that is enough. Fortunately my fluid looks pretty clean and pink at the moment, but it could take a lot of goes if the current stuff is murky.
Another option is to get it flushed so you get all the old fluid out, but I've heard enough tales of that making things worse on older autos that I'm not sure I'd have it done it to mine.
Hi Jim,
Drove it today after just one day since the last outing. The drive was only slightly slow at coming up to scratch.
Prior to this it has been left for longer periods up to a week - then there is no drive for 30 seconds or so.
Tried hard acceleration etc. no noise, changes are very smooth accelerates smoothly to 100 plus.
I would say though that it is a real slushbox by comparison to my 67 yank, but that has had a shift kit and rebuild recently, giving hard positive changes.
The fluid looks clean in the filler, but that is not necessarily true for the torque converter and internals so I will change it this week.
The car has only 40k. mileage so poss fluid never changed.
Thanks for everyone's help.
Graham
Drove it today after just one day since the last outing. The drive was only slightly slow at coming up to scratch.
Prior to this it has been left for longer periods up to a week - then there is no drive for 30 seconds or so.
Tried hard acceleration etc. no noise, changes are very smooth accelerates smoothly to 100 plus.
I would say though that it is a real slushbox by comparison to my 67 yank, but that has had a shift kit and rebuild recently, giving hard positive changes.
The fluid looks clean in the filler, but that is not necessarily true for the torque converter and internals so I will change it this week.
The car has only 40k. mileage so poss fluid never changed.
Thanks for everyone's help.
Graham
tr7v8
New member
If the level is correct then it could be low on pressure. At this point it needs to go to a specialist auto box repairer & get the line pressure checked. A drain down filter change/clean may fix it but it'll need specialist diagnosis.
In answer to Fen you can never completely drain an autobox as about 30% of the fluid staysin the torque converter. Multiple fills & drains get most of it out but even then you'll get some residue in the TC. That's why no warrants an autobox replacement unless it has a replacement TC at the same time.
As boxes age the seals go hard & leak increasing the flow needed to make actuators work, at the same time the pump pressure drops giving the symptoms you have.
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