I've got a 97 Pontiac Sunfire with about 108,000 miles on it and was looking into getting the transmission fluid replaced with synthetic. Synthetic oil in my engine made a big difference in performance and I've been having some hard shifting in the automatic transmission anyhow. The car is well maintained but has a sealed transmission system which leads me to suspect that the fluid may not have been changed every 30k. I work in a store with a service department which carries Mobil 1 and Royal Purple synthetic AFT and Valvoline Max-Life (which one of the mechanics recommended because of the detergent package). I'd rather go synthetic but I don't really want to pay for 4 gallons of Royal Purple or Amsoil to flush and fill. Does anybody have any recomendations?
Trans fluid in a 100k+ car
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My neighbor had a Grand Am and she walked over one day when I was working on my car because her tranny was slipping,so I was going to check the fluid and much to my surprise,no dipstick???????? Then I learned about the sealed tranny. What in the world is the purpose of those? How can the fluid be changed/checked/maintained on these?
It isn't sealed, it's just dipstick-less. The transmission utilizes a fill plug/overflow plug setup for filling and level check. Very similar to a manual transmission.
Manual transmissions have a drain plug.
Here's what I would do given the mileage and unknown history:
If your AT has a drain plug then drain and refill with whatever suitable ATF you choose. If there is no drain plug then a pan drop is even better, but more work.
Use the car for a few weeks to make sure the transmission isn't acting up (possibly slight improvements from some restored friction modifiers is fine). If all is well then drain again and do the cooler line purge to replace a much higher percentage of the ATF.
In the past fourteen years I have only purchased one car with an automatic transmission. It had 80k+ miles when I got it, and the above is what I did with its ATF. I noticed no change in performance after the initial drain/fill, or the cooler line flush a year later.
If you are having erratic hard shifts there may be issues that fresh ATF will not resolve.
I am NOT an expert here, others may offer better advice.
Here's what I would do given the mileage and unknown history:
If your AT has a drain plug then drain and refill with whatever suitable ATF you choose. If there is no drain plug then a pan drop is even better, but more work.
Use the car for a few weeks to make sure the transmission isn't acting up (possibly slight improvements from some restored friction modifiers is fine). If all is well then drain again and do the cooler line purge to replace a much higher percentage of the ATF.
In the past fourteen years I have only purchased one car with an automatic transmission. It had 80k+ miles when I got it, and the above is what I did with its ATF. I noticed no change in performance after the initial drain/fill, or the cooler line flush a year later.
If you are having erratic hard shifts there may be issues that fresh ATF will not resolve.
I am NOT an expert here, others may offer better advice.
I would also look into Auto-Rx. I know that some folks get tired of hearing that, but it is a good product for this type application.
Rather than the expense of Synthetic ATF go with more frequent changes. Eventually, after a few drain and fills. Go with maybe Mercon V. (IMHO)
I may try that.
I'll have to look into that.
It's a 90's 4spd automatic on a 4 cylinder, they all have issues, but I'm hoping that new (and maybe smoother) fluid will help with that. It's not having issues like my old Ford which had transmission issues but I've been told that there is a chance there's wear that's causing the shifting issues.
You're smart NOT to go synthetic on a poorly maintained in a questionable condition transmission.
Maxlife is 1/2 the cost of M1/RP and won't take away from the beer budget. I would also not spend ANY money on any additves. Pennzoil highmileage ATF is an option. But, I would probably just use the Wallyworld maxlife equivalent since its the cheapest.
Buy a filter kit and change it. If there is no drainplug, investing $6 for a drainplug kit would be smart with the pan off and will ease future maintenance.
Flush it with Maxlife, or drain/refill it 3-4 times with a 15-minute drive in between each drain/refill. If the transmission shifts perfectly with the new fluid for ~10k miles, then upgrading to a synth or DexronVI are options.
Maxlife is 1/2 the cost of M1/RP and won't take away from the beer budget. I would also not spend ANY money on any additves. Pennzoil highmileage ATF is an option. But, I would probably just use the Wallyworld maxlife equivalent since its the cheapest.
Buy a filter kit and change it. If there is no drainplug, investing $6 for a drainplug kit would be smart with the pan off and will ease future maintenance.
Flush it with Maxlife, or drain/refill it 3-4 times with a 15-minute drive in between each drain/refill. If the transmission shifts perfectly with the new fluid for ~10k miles, then upgrading to a synth or DexronVI are options.
When I did my wife Focus I just used Mercon V at work and it has been great. No need to go Full-On Syn if your livin in a budget.
why put mercon V in a GM car that requires DEXRON?
Drain and fill. You're asking for trouble by flushing a trans with a questionable service history at 108k.
I'd drop the pan, install a drain plug, and change the filter. Stock up on the dino DexIII of your choice and drain/fill with the next few oil changes.
I'd drop the pan, install a drain plug, and change the filter. Stock up on the dino DexIII of your choice and drain/fill with the next few oil changes.
i like maxlife atf dex/merc works very well in my yota and it meets T-4 specs too
What ever you do, you first need to drop the pan, have a look, clean things up, replace the filter and refill with ATF. If things were very clean looking you could go right to synthetic. If it was really dirty, then use normal ATF and maybe replace the filter in a month again. If things were in between, then go with normal ATF, do another drain/refill in a week or two, then you can decide whether to stay with normal ATF or go with synthetic.
I have a hard time believing synthetic oil made a BIG difference. Synthetic oil is excellent oil, and starts easier in the cold winter, can go longer between oil changes and provides a slight improvement in performance.
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