RPM fluctuation ~200 RPM
#1
RPM fluctuation ~200 RPM
Hi,
First post. Got my V50 (2.4i non-turbo, automatic, front wheel drive) about a year ago and have noticed that while cruising, highway or city, the tach will jump about 200 rpm and then fall back to normal. happens every 10 seconds or so...but not all the time. Sometimes it jumps more like 600 rpm but rarely. Seems better when using cruise control but it still oscillates every once in a while. Most noticeable when the engine is under strain i.e.: hills. Thoughts? Torque converter or electronic throttle? Hoping not the tranny - got the Volv after the transmission melted in my Acura. Love the car, have done wheel bearings, upper radiator hose (pita), and plan on a slight drop, sway bar + building an intake with an inline filter so it can still take air in through the snorkel. Want to keep this girl going, but worried about this rpm thing, I have a vid of the tach somewhere, will upload when I find it. Any advice or insight is much appreciated.
Thanks,
Dan
First post. Got my V50 (2.4i non-turbo, automatic, front wheel drive) about a year ago and have noticed that while cruising, highway or city, the tach will jump about 200 rpm and then fall back to normal. happens every 10 seconds or so...but not all the time. Sometimes it jumps more like 600 rpm but rarely. Seems better when using cruise control but it still oscillates every once in a while. Most noticeable when the engine is under strain i.e.: hills. Thoughts? Torque converter or electronic throttle? Hoping not the tranny - got the Volv after the transmission melted in my Acura. Love the car, have done wheel bearings, upper radiator hose (pita), and plan on a slight drop, sway bar + building an intake with an inline filter so it can still take air in through the snorkel. Want to keep this girl going, but worried about this rpm thing, I have a vid of the tach somewhere, will upload when I find it. Any advice or insight is much appreciated.
Thanks,
Dan
#2
I haven't had my V50 long enough to get really familiar with the transmission yet, but it sure sounds like the torque converter is going in and out of lockup mode.
As with pretty much any vehicle with an automatic transmission, the first thing to check is always fluid level and condition. I've found that you can solve a host of problems with nothing more than a cheap and easy drain-and-fill.
Transmission Fluid Drain and Fill DIY - General S/V40 - Volvo V70R
As with pretty much any vehicle with an automatic transmission, the first thing to check is always fluid level and condition. I've found that you can solve a host of problems with nothing more than a cheap and easy drain-and-fill.
Transmission Fluid Drain and Fill DIY - General S/V40 - Volvo V70R
#3
The transmissions in these cars are electronically controlled and use solenoids to control lock up, line pressure and shift feel. If you are on a steady road cruising, flat, no headwind, then I do not see any reason for the computer to be modulating the lockup solenoid. However, if the engine starts to lug a bit due to a grade in the road, then it can adjust the amount of lockup to not lug the engine.
Older cars had a firm ON/OFF lock up solenoid that was somewhat harsh when it needed to disengage. Newer cars have adopted a "modulated pulse width" approach to smooth out these transitions. Modulated pulse width is just another way of saying a fast ON/OFF signal generated by the computer to transition the position of the solenoid.
Older cars had a firm ON/OFF lock up solenoid that was somewhat harsh when it needed to disengage. Newer cars have adopted a "modulated pulse width" approach to smooth out these transitions. Modulated pulse width is just another way of saying a fast ON/OFF signal generated by the computer to transition the position of the solenoid.
#4
Thanks to both of you. I am planning on a drain and fill asap. And that pulse modulation makes sense, except for I can actually feel a difference in the speed when the revs change - I assume that shouldn't be the case? Is it worth changing the solenoids and sensors? Are they known to fail? I had to change several on the Acura...but that tranny sucked.
Thanks!
Thanks!
#5
Draining and refilling the transmission won't hurt anything but it generally does not fix anything either. Make sure that you use the correct fluid. Don't rely upon Uncle Elmer to give advice on what his daddy used for 40 years.
I'm going to assume that you have the AW 55/50 transmission, 5-speed automatic. If so, use Mobil 3309 fluid. If it isn't the transmission you have, then use what is correct.
I'm going to assume that you have the AW 55/50 transmission, 5-speed automatic. If so, use Mobil 3309 fluid. If it isn't the transmission you have, then use what is correct.
#6
Underst8, I feel your pain - my other road trip car is a 1st generation Acura MDX, and I'm babying it along at 230,000 miles.
With modern transmissions, cleaner fluid helps by virtue of removing some of the particulate matter that can gum up valve bodies and shift solenoids (which are basically electromagnets, so they tend to capture metallic debris). The cleaner your fluid, the less debris, and ipso facto, less potential for that debris to gum up the works. Additionally, transmission fluid has additives that do wear out, so I'm a big fan of keeping the fluid cleaned (I've probably done four drain-and-fills on my Acura over the last 70,000 miles, figuring that it's dirt cheap compared to a new tranny).
I got my last Volvo - an '01 V70 T5, for chump change because it had a bad flare going into second gear. I changed out a servo cover (that was under recall but that had never been done), put in new fluid (a 100% swap using the kit from IPD), and re-trained the tranny with some controlled driving around the neighborhood, and it shifted like a new car at well over 200,000 miles.
I've already picked up a case of 3309 for my '05 V50.
With modern transmissions, cleaner fluid helps by virtue of removing some of the particulate matter that can gum up valve bodies and shift solenoids (which are basically electromagnets, so they tend to capture metallic debris). The cleaner your fluid, the less debris, and ipso facto, less potential for that debris to gum up the works. Additionally, transmission fluid has additives that do wear out, so I'm a big fan of keeping the fluid cleaned (I've probably done four drain-and-fills on my Acura over the last 70,000 miles, figuring that it's dirt cheap compared to a new tranny).
I got my last Volvo - an '01 V70 T5, for chump change because it had a bad flare going into second gear. I changed out a servo cover (that was under recall but that had never been done), put in new fluid (a 100% swap using the kit from IPD), and re-trained the tranny with some controlled driving around the neighborhood, and it shifted like a new car at well over 200,000 miles.
I've already picked up a case of 3309 for my '05 V50.
#7
Thanks Tony and Habby. I will look for that Mobil fluid and check out IPD - have bought from them before. Will look into this servo cover as well, if this trans has it.
I have run a combo of Redline street and racing formulas in a few cars and it seemed to really help the tranny's shift more appropriately [i.e.: fewer/better friction modifiers and less clutch pack slipping (quicker engagement, less wear), not as smooth but better for the packs - to habbyguy's point about additives wearing out or not having as long a life in crappy fluid]. Did a drain and fill every 15k on the Acura, which I do think extended the life. Will have to look into Redline for this tranny but I will run straight Mobil for now, unless anyone has experience with Redline or Royal Purp in these.
One more question, might have been answered with a search but I figured it's appropriate for this thread...with the Acura it was a 3 quart drain and fill, out of 9 quarts, every 15k, Is that the same procedure for this car more or less (as opposed to a full change?} I know that changing all the fluid can actually be bad for a transmission that has some miles on it.
Thanks very much for all your help/
I have run a combo of Redline street and racing formulas in a few cars and it seemed to really help the tranny's shift more appropriately [i.e.: fewer/better friction modifiers and less clutch pack slipping (quicker engagement, less wear), not as smooth but better for the packs - to habbyguy's point about additives wearing out or not having as long a life in crappy fluid]. Did a drain and fill every 15k on the Acura, which I do think extended the life. Will have to look into Redline for this tranny but I will run straight Mobil for now, unless anyone has experience with Redline or Royal Purp in these.
One more question, might have been answered with a search but I figured it's appropriate for this thread...with the Acura it was a 3 quart drain and fill, out of 9 quarts, every 15k, Is that the same procedure for this car more or less (as opposed to a full change?} I know that changing all the fluid can actually be bad for a transmission that has some miles on it.
Thanks very much for all your help/
#8
I'm nearly certain that your tranny won't have a servo cover issue.
I believe that (like the Acura) you'll get 3-4 quarts out with a drain. I'd suggest that if the fluid is pretty dark and/or burnt that you do at least 2-3 drain-and-fills to get the fluid as clean as possible.
And FWIW, the issue with new fluid hurting a tranny is probably an urban myth based on the fact that if you power flush (something you won't do in your driveway!) a transmission, you can stir up some sediment which will end up clogging up your valve body and/or shift solenoids - I really can't imagine new (correct) fluid ever hurting a transmission.
And FWIW, I've had great luck with LubeGard Platinum additive - though I've never used it in a Volvo, but it worked very well in my son's Subaru, and in a buddy's Honda (similar to my MDX tranny). There are a lot of great reviews of the stuff.
I believe that (like the Acura) you'll get 3-4 quarts out with a drain. I'd suggest that if the fluid is pretty dark and/or burnt that you do at least 2-3 drain-and-fills to get the fluid as clean as possible.
And FWIW, the issue with new fluid hurting a tranny is probably an urban myth based on the fact that if you power flush (something you won't do in your driveway!) a transmission, you can stir up some sediment which will end up clogging up your valve body and/or shift solenoids - I really can't imagine new (correct) fluid ever hurting a transmission.
And FWIW, I've had great luck with LubeGard Platinum additive - though I've never used it in a Volvo, but it worked very well in my son's Subaru, and in a buddy's Honda (similar to my MDX tranny). There are a lot of great reviews of the stuff.
#9
I'm nearly certain that your tranny won't have a servo cover issue.
And FWIW, the issue with new fluid hurting a tranny is probably an urban myth based on the fact that if you power flush (something you won't do in your driveway!) a transmission, you can stir up some sediment which will end up clogging up your valve body and/or shift solenoids - I really can't imagine new (correct) fluid ever hurting a transmission.
And FWIW, the issue with new fluid hurting a tranny is probably an urban myth based on the fact that if you power flush (something you won't do in your driveway!) a transmission, you can stir up some sediment which will end up clogging up your valve body and/or shift solenoids - I really can't imagine new (correct) fluid ever hurting a transmission.
Thanks again!
#10
Glad to hear it's helping. My '05 V50 had a few bad habits when I bought it - clunky up- and down-shifts occasionally, and occasionally it just got lost in the middle of a shift.
So... I did a drain-and fill. It was my first one on this car, so I was surprised when I got about 4.5 quarts of fluid, but figured that must be right. So I put that much back in.
Fast forward a week and I did another drain-and-fill, and got close to 5 quarts out. As I was adding some fluid back in, I started doubting that the fluid level was correct, and checked the level after adding three quarts... only to find it was pretty much spot-on. Yikes... the previous owner had probably just kept adding fluid when he thought it was necessary? My mistake was making the assumption that the fluid level was correct in the first place, of course.
Anyway - now it shifts a LOT better. Once in a blue moon, it'll exhibit a kind of clunky downshift to 1st gear, but I'm pretty certain one more drain-and fill will most likely take care of that.
You don't really have to wait 1000 miles to do your next d-n-f, just drive long enough to ensure that the fluid is well and truly intermingled. Keep us posted.
So... I did a drain-and fill. It was my first one on this car, so I was surprised when I got about 4.5 quarts of fluid, but figured that must be right. So I put that much back in.
Fast forward a week and I did another drain-and-fill, and got close to 5 quarts out. As I was adding some fluid back in, I started doubting that the fluid level was correct, and checked the level after adding three quarts... only to find it was pretty much spot-on. Yikes... the previous owner had probably just kept adding fluid when he thought it was necessary? My mistake was making the assumption that the fluid level was correct in the first place, of course.
Anyway - now it shifts a LOT better. Once in a blue moon, it'll exhibit a kind of clunky downshift to 1st gear, but I'm pretty certain one more drain-and fill will most likely take care of that.
You don't really have to wait 1000 miles to do your next d-n-f, just drive long enough to ensure that the fluid is well and truly intermingled. Keep us posted.
#11
When I do a cold drain on an AW55/50 I typically get right at four quarts. If I let it drain a few days, you will get more, that's just fluid dynamics.
Make sure that you are checking the fluid level when hot and idling.
There is nothing wrong with fresh fluid and I think that it is a good idea. However, your rough shifting is caused by solenoids that are failing. While many people believe that small dirt particles cause them to stick, it is actually the coil in the solenoid that goes bad. The increasing temperature of the transmission increases the ohms and the solenoid doesn't pulse as needed to create smooth shifts.
The final solution is to install new solenoids. The prices have come way down. I always use Rostra.
https://www.ebay.com/itm/AW-55-50SN-...O/190953513081
Make sure that you are checking the fluid level when hot and idling.
There is nothing wrong with fresh fluid and I think that it is a good idea. However, your rough shifting is caused by solenoids that are failing. While many people believe that small dirt particles cause them to stick, it is actually the coil in the solenoid that goes bad. The increasing temperature of the transmission increases the ohms and the solenoid doesn't pulse as needed to create smooth shifts.
The final solution is to install new solenoids. The prices have come way down. I always use Rostra.
https://www.ebay.com/itm/AW-55-50SN-...O/190953513081
#12
FWIW a copper coil (electromagnet) is one of the most failure-proof devices around. If the coil doesn't open up, it'll pretty much work forever. I changed all the shift solenoids out on a VW Jetta turbo I bought - that tranny was doing nothing at all right when I bought it. All of the shift solenoids were still electrically 100% fine - they all measured to spec, but the pistons inside some of the solenoids were no longer free to move because of contamination. I didn't even try a fluid change on that transmission. They make kits to disassemble, clean and rebuild the shift solenoids that have become contaminated - after all, when you suspend an electromagnet in a bath of fluid with tiny little metal particles floating around, they're going to get attracted to the electromagnet (just like they do to the magnetic drain plugs, or to the magnets in the external add-on filters).
I've never considered the resistance change in the coil as a factor - it's interesting (since it is a fairly large percentage change over the potential temperature range from parked in Anchorage to driving around in Arizona today at 110°). But that change will be the same for a new shift solenoid, but I can see how a misbehaving tranny that's far above normal temperature is only going to make it worse by increasing the resistance of the shift solenoid coils, which could affect their performance - though I'd suggest that would be a much bigger problem with a shift solenoid that's contaminated than with one that's new and clean.
To me, the cost and simplicity of doing a fluid change makes it a good first step in chasing down a lot of transmission problems. Sure, it might not help, but the first two drain-and-fills have sure fixed some problems in my "new" Volvo V50 (2005 2.4i), though as I'd mentioned in a previous post, the PO had overfilled the tranny, which was no doubt part of the problem.
I've never considered the resistance change in the coil as a factor - it's interesting (since it is a fairly large percentage change over the potential temperature range from parked in Anchorage to driving around in Arizona today at 110°). But that change will be the same for a new shift solenoid, but I can see how a misbehaving tranny that's far above normal temperature is only going to make it worse by increasing the resistance of the shift solenoid coils, which could affect their performance - though I'd suggest that would be a much bigger problem with a shift solenoid that's contaminated than with one that's new and clean.
To me, the cost and simplicity of doing a fluid change makes it a good first step in chasing down a lot of transmission problems. Sure, it might not help, but the first two drain-and-fills have sure fixed some problems in my "new" Volvo V50 (2005 2.4i), though as I'd mentioned in a previous post, the PO had overfilled the tranny, which was no doubt part of the problem.
#13
After handling thousands of Volvos and diagnosing dozens of rough shift conditions in the AW 55/50 transmission, my conclusion is that while the fluid might be dark and dirty, the shifting problems that show up as the transmission comes up to temperature are solenoid related.
Now, on any mechanical issue there is a bell-shaped curve where most of the solutions are present. There are a few outside the norm of course. In 100% of the cases thus far, we have corrected the rough shifting by replacing the solenoids and fluid. Changing the fluid alone did not correct any issues in our early attempts. After that, we do a fluid change and solenoids.
Now, on any mechanical issue there is a bell-shaped curve where most of the solutions are present. There are a few outside the norm of course. In 100% of the cases thus far, we have corrected the rough shifting by replacing the solenoids and fluid. Changing the fluid alone did not correct any issues in our early attempts. After that, we do a fluid change and solenoids.
#14
Tony, I think we are saying the same thing, but because of our position, we have different approaches (and rightly so). As a shadetree mechanic, I have the luxury of being able to try the lower-percentage approach (changing the fluid and hope that it will eventually correct a sticking valve or shift solenoid). If it works, great - I saved some money. If it doesn't, I don't get mad at myself. ;-) As a pro, you have to send the car out the door working 100%, and there's no way to know whether a solenoid that was "fixed" with a fluid change will stay "fixed", or if possibly it cleaned it up just enough to just work temporarily, maybe upsetting a customer if and when it starts to malfunction again.
#15
My comments are based solely upon the data that I have accumulated. I am not opposed to doing the transmission fluid change, in fact, we do so when we change the solenoids. You are correct that the lower cost alternative is the fluid change only. I am suggesting that it may not be completely successful.
I've been buying the Mobil 3309 fluid in the blue bottle and it costs me about $7.25 per quart. I'm pretty picky about the cars that we send out so I've been changing solenoids on any AW 55/50 that is rough shifting.
If changing the oil works for you then that is great and I support your effort!
I've been buying the Mobil 3309 fluid in the blue bottle and it costs me about $7.25 per quart. I'm pretty picky about the cars that we send out so I've been changing solenoids on any AW 55/50 that is rough shifting.
If changing the oil works for you then that is great and I support your effort!
#16
Tony, you mentioned checking the tranny fluid hot (which I agree is the best way). Is there a trick you use for the S40 / V50? There's no way in the world I can get to my dipstick without the front of the car lifted and the splash pan removed... not exactly the most conducive situation for a quick check, and I wonder how that affects the reading (since the transmission is far from level).
FWIW, when I was filling it during my last drain-and-fill, I used the "cold" section of the dipstick as an indicator, but that was after the car hadn't been running for hours. It was reading at the top of "cold" area on the dipstick.
What's the proper procedure for getting an accurate fluid level check?
FWIW, when I was filling it during my last drain-and-fill, I used the "cold" section of the dipstick as an indicator, but that was after the car hadn't been running for hours. It was reading at the top of "cold" area on the dipstick.
What's the proper procedure for getting an accurate fluid level check?
#18
#19
Thanks, Tony... There's no way I could get to the dipstick on mine from up top. I think I might be able to move / lose a couple hose supports and create enough gap to get my hand on the dipstick, but right now, it's not even close. I like your suggestion to just use the typically drained amount... that sounds like a great idea and won't leave me wondering just how far off the dipstick is because the nose of the car is in the air (and my driveway slopes up, making it worse). I can't turn it around, because then I get more sun (and in August in Arizona, you don't want more sun...).
#20
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