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850 AW50-42LE Tcu differences

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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Angelofhevn
Posts: 6
Joined: 20 May 2019
Year and Model: 1996 855 t5
Location: Finland
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Volvo Repair Database 850 AW50-42LE Tcu differences

Post by Angelofhevn »

Hello i currently own a 1996 Volvo 850 turbo with some engine mods.
18t, 3" turboback, Na cams, greens, VastTuning m4.4 etc.
Its running nicely but im wondering about the auto tcu. Is there different versions of the tcu boxes with different shift patterns or upgrades between revisions of the tcus.

When i floor it it gets quick to powerband but the gearbox got long gear spacings and i think it shifts too early, because i got the NA cams and a 18t it kinda has to work harder after a shift to get into the powerband again.
I would probably pick up 1s 0-100kmh with a little more rpm before shifting!

I wanted to do the pot mod to get faster shifts and less clutch slippage (mine doesnt slip but gets longer life when it grips harder) but mine does not have the famous big resistors that you swap for a pot where they should be on tutorials and on the other side of the board there are another pair of big resistors but they arent same value as the tutorial.

So my questions are:
1. Is there difference in NA and T5 TCMs. Like would the NA one rev higher before it shifts?
2. Difference in 850s vs early x70s before 1999 TCUs.
3. I know theres different TCM boards in 850 turbos but is one "better" in any way and wich ones are direct swap?

I attatched some pictures from the inside of my 1996 T5 TCM if anyone is intrested. :roll:
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hausmeister
Posts: 572
Joined: 22 July 2006
Year and Model: 1995 850T5-R
Location: Austria
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Post by hausmeister »

I can answer 1. as per specs the turbo transmission has a higher stall rpm and locks up clutch later and only in 4th, so an NA TCU would not be an improvement for you.

If you found something out about aftermarket solutions or other improvements please let us know ;)
Sorry for the late revive of this thread, Would be good to know if there any easy options for tuning.
850 T5-R '95 auto Image

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