Good morning. The Aisin 5a in my Saab 9-5 was fine so - obviously - I had to mess with it. I changed over to Redline D4 ATF. The old fluid wasn't burnt, it smelled good, etc. The car has shown the transmission fault indicator twice in as many weeks since the change.
The first it happened I checked the fluid level, then disconnected the battery briefly. The indicator stubbornly remained lit on the following drive only to clear itself spontaneously on the second trip. The Saab shop found no stored codes.
The indicator lit again yesterday after a pretty gentle 15 mile drive. The trans shifted fine before the indicator came on but it went into limp mode and shifted hard afterward when using the gear selector to start in a lower gear per the owner's manual.
The lore used to be that switching to synthetic motor oil in an engine raised on dinosaur oil could lead to new leaks caused by the more-slippery molecules getting past aging seals. Could the new ATF be "too good" for an aging-but-working-fine transmission? I wonder if the D4 might actually be a tad too slick, causing very slight slippage and raised fluid temps.
What is most likely - new fluid was a coincidence, trans was on its way out; new fluid could be the problem, switch it back; dude you are dumb that's the incorrect fluid; or ?
For all the good things I've experienced and heard about Redline, I've seen whispers online that the D4 ATF is better as a manual gear oil than as the ATF it's supposed to be. It sure worked great in my E39's 5-speed manual, but in actual automatic transmissions I've never used any ATF other than what the book asks for, usually a good old conventional Valvoline product. Slushboxes are strange and complex devices that I never want to deal with repairing, so I err on the side of caution; the right fluid, IMO, is whatever is most similar to what was already in there.
not sure its in the 9-5... but I seem to remember(15+ years ago) the 9000 requiring some very special tranny fluid....
In reply to oldeskewltoy:
The AT in the 9000 was a ZF unit. IIRC, they didn't require special fluids, but frequent fluid changes and prayers, lots of prayers. And restraint, because full boost pressure upshifts are hard not to do.
The 9-5 AT is tough, but not bullet proof. Is it possible that the trans can be recalibrated through tech-2? Many of the industrial vehicles that I work with respond well to a trans fluid/filter change followed by a recalibration.
I've had good results with D4 ATF, but that's been in Ford T5s that called for ATF to begin with. Ironically, I've never put D4 ATF in an auto 
Those Aisan transmission all call for a magic and expensive fluid. Most trans shops don't use it, they use a universal synthetic with an additive, but I've always used the proper stuff. I'd wonder if the Redline isn't a bit too thick, so it doesn't see the correct pressures on output side of some small holes.
Either that, you loosened up some junk and jammed a solenoid, or it was just ready to break.
What year saab? 99-01 calls for dexron 3. 02-09 calls for jws3309 automatic trans fluid. 10-11 calls for saab pn93 165 147.
If its older id have too pull out one of our older books. Maxlife universal atf is safe for everything except 10-11
It is an '02 Aero wagon. Thinking at this point it will be best to have the shop drain and fill with the correct fluid and see what happens.
Never used Redline ATF. I have always go to Ames oil and never had an issue.
conesare2seconds wrote:
It is an '02 Aero wagon. Thinking at this point it will be best to have the shop drain and fill with the correct fluid and see what happens.
Have it flushed, i know this forum is full of horrors about it but it is the way to get the full system drained. Any decent shop uses a fluid exchanger in this day and age.
Did you change the filter ?
May not be the fluid after all.
Auto transmissions are just hydraulically operated, so I question the necessity to use the magic elixor.
No filter in this trans. Weird, I know.
iceracer wrote:
Auto transmissions are just hydraulically operated, so I question the necessity to use the magic elixor.
Different fluids and additives can react with one another though. Unless you get every last drop of the old stuff out you run that risk.
I'll have the shop check for stored codes again before giving up on the redline. Turns out there is a speed sensor in the trans that can fail intermittently. It's not too spendy, thankfully. If no stored codes will flush the fluid.
In reply to dropstep:
Youve had a personal good experience with a flush? Cause i sure never have...with the fancy exchangers at that..
FWIW, my '04 9-5 had D4 in it for about 120k miles. I ended up switching back to the 3309/Toyota fluid in part because it's quite a bit less expensive (~$72/case from Amazon). I couldn't tell any difference in shift quality, cold or hot.
chiodos wrote:
In reply to dropstep:
Youve had a personal good experience with a flush? Cause i sure never have...with the fancy exchangers at that..
Ive done over 300 of them with our RTI machine and have never had an issue. Between 2 guys we average 150 flushes a year. My boss has 200k on his original 4l60E and it gets flushed every 50k.
Flushes get a bad reputation for some reason, as long as your trans is outputting atleast ten psi our machine works great.
Even my wagon has been flushed. I abuse that c4 with no issues.
Many people think that a flush will cure an already ailing transmission. When they then fail shortly after the flush it has to have been caused by the flush.
