Rough start/no start after tranny flush & b4 servo Topic is solved

Nathan79 · Post by **Nathan79** » 18 Sep 2018, 21:59

Hello all,
07 xc70. 160k.
Noticed slight shift flares between 2nd & 3rd about a month ago...just last week the flares were noticeable in & put of all gears.
Performed tranny fluid flush (oil that came out was brown & very "thin" feeling) & noticed immediate improvement, but still slight flares between 2nd & 3rd. Next day swapped out B4 servo. Went to test drive it after completion & it died while in reverse out of the garage. Fired right back up & went on test drive noticing very reduced power along with shift flares still in 2nd & 3rd. Parked it for 10 minutes...went to drive it again & it died after firing it up (while in park)... Now it won't even fire up while cranking...also feels very sloppy or rough while cranking...PLEASE HELP.

Thanks in Advance!
Nathan

Georgeandkira · Post by **Georgeandkira** » 19 Sep 2018, 07:57

I believe the B4 servo covers were redesigned / corrected / strengthened sometime around 2003-2004. Was your replacement purchased new? Did it look like the one you removed? I'm concluding here (guessing) that replacing the B4 servo cover mightn't've been necessary. At around $20 though, you didn't risk much money.

During the refilling of transmission fluid might have you unseated or damaged an air handling hose?

Also: Did you do a pump-out of a drain & fill?
While you're at it check to see if your 160K car has a serviceable fuel filter external to the tank.

Nathan79 · Post by **Nathan79** » 23 Oct 2018, 21:53

Rough start & bad idle was due to bad connection of Air intake hose, that I replaced a few days prior,
Problems with shift flares are STILL problematic anytime I get RPM'S over 2800... As long as acceleration stays below that, it shifts smooth.

Post by **precopster** » 23 Oct 2018, 22:27

They sometimes take many miles to adapt to having new fluid and especially a new B4 servo which controls transition of 2nd to 3rd gear shift by pushing on a friction band.

There is a fluid counter reset available at the service division and also a drive cycle adaptation you can do however you need the Volvo diagnostic tool and software to place it into "Adaptation"

Best to keep driving it and things will likely improve. Just treat it gently as it "relearns" new shift behavior. If you don't have the tool it may take 400-500 miles to adapt

Georgeandkira · Post by **Georgeandkira** » 24 Oct 2018, 05:55

To Nathan79: If you ever post back please include details of your fluid change.
Brand / type of fluid used and whether you performed a drain & fill or a pump-out.

Post by **oragex** » 24 Oct 2018, 06:55

What exactly was replaced at the B4?

Nathan79 · Post by **Nathan79** » 25 Oct 2018, 22:51

Fluid was pumped out. About 14 quarts in total was replaced with Toyota type IV...
B4 piston was changed (OEM kit online)
I've Been driving it since all the issues before & after the B4 servo & tranny flush, & ALL shifting issues are the same (probably about 700 miles). So I keep it under 2800 rpms & "miss daisy" in the back is just peachy keen... Meanwhile I miss my turbo action with smooth shifting!!

I've heard of folks having some minimal success with "adaptation flash". Has there ever been any full cures? I'm sure I could be persuaded by some EXPERT KNOWLEDGE as to why it's necessary, (& its only about $200 vs tranny R&R/ overhaul/ rebuil or replace price ranges)

My limited experience here has me thinking it's the trans valve body\solenoids. If not, then what else could be the issue(s)? How could I further diagnose?

Thanks
Nathan

Post by **precopster** » 26 Oct 2018, 05:07

Are you certain it's the "piston"??

The B4 "piston" is not available online as it's matched with the transmission during machining. The B4 servo piston "cover" is available for about $30 online. In many cases the piston bore has too much friction with the piston and some people have improved shifts from 2nd to 3rd by checking the piston bore for scoring and helping it along with some steel wool.

Are all shifts affected? 1-2 at high revs? 2-3 at high revs? 3-4 at high revs and so on?

We had a 2007 XC70 come through with really strange high-rev shift patterns where it hunted and jerked away in a stuttering pattern. We cleaned out the shift solenoids with a Transgo kit, new fluid and reset adaption. We did the adaptation through Vida. The problems resurfaced immediately.

We eventually replaced the alternator to repair the issue as it wasn't producing clean DC power and caused the solenoids to vibrate and not move in a linear fashion.

Nathan79 · Post by **Nathan79** » 26 Oct 2018, 21:44

Wow! Crazy case there! You don't suppose I have the same kind of issue going on with mine? How did you get the ALT issue diagnosed?

Yes, All shifts are affected. Also a yes for the piston COVER... Part no. 30751262.

Thanks
Nathan

Post by **precopster** » 27 Oct 2018, 00:35

We measured for AC voltage at the battery with engine running. I can't recall the actual amount of AC we measured but it was way more than the alternator should have been producing.

Because the later cars have a different alternator to pre-2004 we didn't have one on hand to swap in as a tester.

Any auto electrician could test it quickly or if you have a good meter you can test yourself. I recall jimmy57 chiming in on some of the threads about acceptable levels of AC voltage measurement. Are you out there jimmy?