P38 4.0 Infamous 4HP22

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T

Tonci

Member
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12
Location
Croatia
So, I have made engine overhoul. After breather misplaced and fixing that i have found out my coil was bad. Two days ago I have replaced the coil and engine is now working perfectly, BUT now I have issue with transmission. When I head problem with vacuume and bad coil engine was shifting normaly and I have moved the car aound the garage. After replacing coil, when shifting to any gear transmision is not engaging. Dashbord and selector are showing all correctly, but I don't think this could cause any kind of problem as this gearbox has mechanical shifter, but ok. First tought was i have disconected domthing when I was reassambling intake manifold after new coils instalation, not the case. So tonight I have tried to change the oil inside the gearbox as next step.
Oil was bad and I have changed oil filter also. There was small amount of debris on magnet (not y=the worst I have seen on BMW's with similar gearbox). When I tried to refil new oil I was able to put in maybe 2.8l and then when I was tring to top it up while engine is running it was like the pump inside transmission isn't working. I wasn't able to add any more oil besides this 2.8l that whent in while cold.
Is it possible that pump stops working overnight?
This is completly new to me.
 
Tonci said:
So, I have made engine overhoul. After breather misplaced and fixing that i have found out my coil was bad. Two days ago I have replaced the coil and engine is now working perfectly, BUT now I have issue with transmission. When I head problem with vacuume and bad coil engine was shifting normaly and I have moved the car aound the garage. After replacing coil, when shifting to any gear transmision is not engaging. Dashbord and selector are showing all correctly, but I don't think this could cause any kind of problem as this gearbox has mechanical shifter, but ok. First tought was i have disconected domthing when I was reassambling intake manifold after new coils instalation, not the case. So tonight I have tried to change the oil inside the gearbox as next step.
Oil was bad and I have changed oil filter also. There was small amount of debris on magnet (not y=the worst I have seen on BMW's with similar gearbox). When I tried to refil new oil I was able to put in maybe 2.8l and then when I was tring to top it up while engine is running it was like the pump inside transmission isn't working. I wasn't able to add any more oil besides this 2.8l that whent in while cold.
Is it possible that pump stops working overnight?
This is completly new to me.
Click to expand...
Did you have the engine out for the overhaul? If you did, odd on you did not refit the torque convertor correctly which has damaged the oil pump drive
 
But torque convertor was left on gearbox. I haven't removed it. Also after first start I was driving car around the garage. So it was working, but maybe you are wright
 
Tonci said:
But torque convertor was left on gearbox. I haven't removed it. Also after first start I was driving car around the garage. So it was working, but maybe you are wright
Click to expand...
If the torque convertor was not held securely in place, it may have partially disengaged from the pump and gradually destroyed it when you put the engine back and ran it.
 
Does sound like the torque converter may have slipped forward as you put it together and it's damaged the pump. Ashcrofts have a bit of info to be aware of when fitting one, AND measurements for how far down it should be seated on to the input shaft here... It'll be a ballache to check it now, but at least you'd know one way or another!

https://ashcroft-transmissions.co.uk/product/torque-converter/

Screenshot 2023-12-31 at 12.37.18.png
 
Last edited:
Same box on the Classic.
The torque converter is not fixed to the gearbox, just pushed on.
They can easily slide forward & fall off if you aren't aware of that. Guess how I know!

It can be an utter PITA to get back onto the box if it has moved forward & esp if it fell off. It's a big & very heavy lump. Again, guess how I know.

I have done it under the car with the box horizontal & it was a struggle getting the input shafts to line up with the box. Couple of lengths of threaded rod screwed into the bosses on the front of the TC do help & LR have a special tool which is basically just that.
Last time I did it I'd had a fair bit of the box apart to replace seals & gaskets so had the box out from under the car. Lifted it with an engine crane so the box was vertical & the TC went on so easily!

I made a small 'T' shaped piece of steel to go up through the round inspection hole in the bottom of the bellhousing to stop it sliding forward.
Bend it so the long part of the 'T' sticks up into the bellhousing against the front of the TC & drill a couple of holes in the top of the 'T' so you can use the small bolts that hold that inspection hole cover on the hold the tool.
Don't use too thin a piece or the weight of the TC will just bend it out of the way & it will fall off again. As before, guess how I know!

There are two slots on the hollow centre shaft which is on the gearbox side of the TC & these engage with & drive the fluid pump in the box.

TC must be checked for correct seated depth as in the Ashcroft link above.
If it isn't then whilst the engine & box can be bolted back together it will damage the pump.
No pump = no fluid pressure = no drive.
 
After the inspection, conclusion is I have wrongly assembled flywheel. Distance between flywheel and convertor was great.
I have to recheck flywheel assembly. Can I shimm the flex plate if necessary? But then again, why should it be necessary?
 
Last edited:
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