5 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH1999 C4 Tip P0740 ? What actually fixes it?
Leading reported evidence
Clean ) and tcc solenoid
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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1
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Suggestion · Original poster
Indie has done ATF + filter (fluid clean) and TCC solenoid.
Leading evidence: 'Clean ) and tcc solenoid' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Clean ) and tcc solenoid' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
Also ensure whoever is replacing fluid is using the correct fluid, as the 996.1 ZF tiptronics have different fluid than the 996.2 Mercedes tiptronics.
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Suggestion · Original poster
My plan is to replace torque converter + valve body together.
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1999 996 C4 Tip. Intermittent P0740 for 8 months. Indie has done ATF + filter (fluid clean) and TCC solenoid. Code still returns every few hundred miles. 4 to 5 shift is sluggish in auto only, manual fine. No shudder, no other codes.
My plan is to replace torque converter + valve body together. Torque converter I can source from Pelican Parts. Stuck on the valve body, 1999 is Version 1 E17 (I think), so TransGo kit won't fit.
Anyone actually resolved a persistent P0740 on a 1999 C4? What worked?
Any tips where I could source a valve body replacement?
Will report back with whatever fixes it.
From all the treads about this, seems the valve body PRV is the problem in these trannys. Won't the 5hp-19 kit fit...? Thats the trans most 99 have
maybe PT3 will see this thread and chime in, he knows....
Thank you for the reply. I decided to order a Sonnax valve body replacement I found on eBay. It's
the
ZF5HP19 (1996-1999) BMW002
. My car was one of the earliest models of the C4 built late 1998, so from what I understand the BMW002 is the correct valve body. For late 1999 built 996s is BMW003 afaik.
Going to swap the entire valve body and also get an OEM torque converter replacement. I really hope that will make the sluggish 4 to 5 shifting go away as well as the CEL.
Let us know how it works out for you. Good luck.
Also ensure whoever is replacing fluid is using the correct fluid, as the 996.1 ZF tiptronics have different fluid than the 996.2 Mercedes tiptronics.
When I purchased my 9961 tiptronic it had red fluid, not the gold/amber of Pentosin ATF 1 or ZF Lifeguard...flushing that out and installing a new filter and Pentosin improved function for me.
I was not experiencing symptoms like yours...
What happens on these ZF5HP Tip Trans is the system pressure runs at ~ 300 psi MAX, the pressure regulator in the valve body " Dumps" fluid to control pressure .... When the valve in the pressure regulator wears and starts to stick in the bore, the pressure can intermittently raise much much higher than 300 psi, and when this happens a little O-ring in the Torque Convertor for the Lock-up Clutch blows out... and you end up with a code P0740.
Yes the fix is a new valve body and torque convertor...
(alternatively if you're a cheap skate and all shifts are still ok, I know of one guy who has been driving for 15 years just ignoring the code )
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