Thread: I would have been happy if my diagnosis was correct, but it need further investigatio

sounds roughly like the TC wasnt installed correctly in the pump drives to me.

especially likely if the cracking on the flex plate is all on the TC side and not the crank side with the Flexplate bent back towards the ring gear.

Originally Posted by Blknight.aus

sounds roughly like the TC wasnt installed correctly in the pump drives to me.

especially likely if the cracking on the flex plate is all on the TC side and not the crank side with the Flexplate bent back towards the ring gear.

thanks Dave for your reply.
This Transmission had it's flex plate replaced before I purchased it, so I suspect the auto mechanic that did the job, did it in an unprofessional way, I had a video scope there today to find the bell housing/ engine retaining bolts had 1 not installed at top ( too hard for them. As mentioned before wrong length bolts used with nuts as spacers) The elderly couple told me a transmission specialist did the work.
I noticed that the flexplate support plate had some burring on part of and edge, there was no corresponding scrape on the TC, it it must be an old war injury.

I've heard of incorrectly fitting a TC to pump. What difficulty is there in fitting the TC to pump? Is there a special procedure to follow?
Thanks Mario

yeap, its pretty major rocket surgery type stuff too.

clean and prelube the seal and the pump drive shaft of the TC
inidentify the engagement dogs on the TC
Identify the engagement slots in the pump (I usually use a clean screwdriver to line them up with an easily identifiable position outside the pump housing)
offer the TC up to the pump/input assembly dead square and with the dogs and slots in alignment
Once you have the TC installed past the seals use a very slight rotating rocking motion on the TC as you gentlypush inwards on the TC and you will feel it touch the face of the pump drive gear and then "drop" as you rotate the dogs into the slots It then slides home

It only moves about an extra 10-15mm or so

you could have also sheared off the Drive splines on the input shaft or the drive plate in the TC.

Thanks Dave , That gives me something to go on , going to love getting a cup full of AT fluid all over me when I pull the TC

But did you step in any poo???





(Sorry for the unhelpful post!)

Hi not uncommon unfortunately, see here for TC height/depth , this will tell you if the tangs are fully engaged, scroll to bottom of page.
Ashcroft Transmissions - ZF4HP22

Regards Ian Ashcroft

Thank you Ian for your input.
Ready in fitting torque converter if nor properly seated to pump can break pump immediately, I've done 18,000 kms since I bought it before it stopped.

The most common cause of drive plate failure I have come across is due to a dowel between the engine and bell housing going missing. The alignment of the engine and trans centrelines is super critical. It is possible that after cracking the drive plate the converter nose no longer engages the pump properly, causing failure there. Hydraulic pressure in the converter pushes against the crank shaft and a broken flex plate may allow it to move too far forwards.