To Flush or not to Flush? Advice needed....

[jeremyquinn]

Hello guys, haven't checked in for a while, but I have learned a ton and got great advice in the past.

I inherited a 98 Plymouth Voyager with the 3.0 engine (from my late and awesome grandmother) with 86k on it. While getting an oil change at the local spot they said the tranny fluid smelled burnt and recommended either the drain and refill or the full blown flush that will get everything out and replace with syn fluid.

Thoughts?.....

 

[StevieC]

These transmissions do run hot and are prone to failure due to heat and poor design. The valve body also has problems with gumming up with debris from worn clutch pack material.

I would have it flushed and refilled with a High-Quality synthetic that meets your owners manual specifications. Do not use whatever the lube-shop uses unless its the right stuff or you could end up with a damaged transmission.

Also when it's due for another change I would have the filter changed with the fluid. Have to drop the pan to get at. (Not necessary for this change)

I would also smell the fluid yourself and look at the colour before taking the "Lube Place" word for it, they often try to push stuff that isn't needed!

Also if you intend on keeping this van a while I would invest in a thermostatically controlled auxiliary Transmission Fluid cooler to be installed to cut down on the heat. This can be done at any transmission shop fairly cheap and will greatly reduce the chance for transmission failure.

(Pops worked for Chrysler and is a retired mechanic)

 

[jeremyquinn]

Stevie! Thanks dude, you are the man. I appreciate you taking a few minutes to share your expertise with me. Going to smell and if needed flush this week. Maybe they can even do the cooler since they are a full blown shop. Probably the most clean and orderly full blown shop I've ever seen.

Yes, I do plan on keeping it until it just doesn't make sense from a financial standpoint to fix it anymore. Hoping to get another 5 years or 100k out of it.

 

[StevieC]

If you put the cooler in you will definitely get the time out of the tranny... Make sure though it is a Thermostatically controlled unit that will bypass the cooler if the fluid is too cold because if not then your transmissions torque converter will not go into full-lockup and cause poor fuel economy and excess wear.

You're welcome... Glad I could share what I know via my dads experience and can help save you some money...

Also the 3.0 Litre engine is a very good engine that Mitsubishi built for Chrysler, but it can be an oil burner in some cases, so keep an eye on the oil. Also change the PCV valve every 30,000 miles or so as they tend to gunk up and cause oil burning due to poor placement and design!

Happy driving!

 

[jeremyquinn]

Again, great tips.

They put in Castrol Syntec and I swear it runs smoother (had dino in there before), but the reason I was thinking for it running smoother was because it was probably a little short on oil as I hadn't changed it or checked it in 6 months (3.5k miles).

So when I ask for the cooler I need to specifically ask for a "Thermostatically controlled unit"? About how much are these with labor?

 

[StevieC]

I'm not sure... My dad got his done on his 94 Caravan for $100 CDN plus tax.

My dad just had the line that would normally return to the transmission from the radiator diverted to the new cooler then back to the transmission. This way he has two coolers, first cooled or heated by the radiator then auxiliary cooled by the new cooler. You can skip the rad all together, he just did it this way on his truck because it was easier...

B&M makes one and you could order it and bring it with you and have them do it, but most likely they will be able to get you one.

Thermostatically controlled or temperature controlled bypass is what you need to ask for.

 

[jeremyquinn]

Thanks brother.

 

[wcbcruzer]

I wouldn't flush it. If you want to install an external cooler, install it after the factor cooler. You might want to throw on a Magnefine inline tranny filter after the cooler too.

 

[bmwtechguy]

If you want to do it right, drop the pan and change the filter, then refill and do cooler line flush with an approved fluid like ATF+4 or one of the premium universal fluids like Amsoil ATF to get all of the fluid changed in the transmission. The cooler and inline filter are good advice if you want to have maintenance-free and trouble-free transmission. I have never used t-stat controlled aux cooler, but I live in South Carolina, so not much of an issue here with over-cooling. But yeah, it takes a few extra minutes to start going into TC lock-up here in the winter.

 

[jeremyquinn]

I now live in Dallas....so what cooler should I get?

 

[StevieC]

Originally Posted By: jeremyquinn
I now live in Dallas....so what cooler should I get?


If you're in Texas I wouldn't worry about a thermostatically controlled cooler... It's warm enough there all year that this won't be an issue... (Saves money)

 

[bmwtechguy]

I have used several coolers from Advance Auto for $50. This is one of the higher cooling capacity (compact) units that have brazed construction. It is not a tube-fin type, but rather a low pressure drop type that is what oems use for towing package ATF coolers from the factory. The tube/fin types will work just fine, too. Stay with one that is 3/4 in thick to fit more easily. Some coolers are 1.5" thick and don't fit well for passenger cars. You should be able to get a really good one for 40-50 dollars or maybe less if you get a smaller one. In Dallas, I would get a larger one.

 

[jeremyquinn]

thanks guys

 

[StevieC]

You're welcome... Let us know what you have done when it's done...

 

[mechtech2]

What trans cooler to get? In Florida or Dallas? As big as will fit!
And run it through the stock radiator one first, like the instructions will tell you to.
Double clamp the rubber lines[where they attach to the steel] and orient the clamp screws 180 deg apart.

 

[StevieC]

If you are going to run it through the Radiator first, then I would get a smaller one as the radiator will do most of the work, and the auxiliary will drop it the extra temperature needed. (This is the setup on my SUV)

If you are in Dalas I wouldn't worry about the thermostatically controlled unit, but it Florida I would get that one because your temperatures still get cool enough IMO to warrant it.

 

[Jim Allen]

Just to add another twist. For people who live in cooler climates, run the hot tranny oil through the oil-to-air cooler first, then to the radiator cooler and back to the trans. The oil-to-air cooler will knock off the big heat but on cold days, the radiator will then warm it.

I've tried it both ways. Interestingly, I found that, even on hot days, the temperature of the oil going back to the trans isn't all that much different (within 15 degrees or so IIRC) with either method, but on cold days the oil going back to the trans was considerably warmer. To quantify, the testing was done in Grand Junction, Colorado, which runs from generally no lower than the 20's in winter to about 100 in the summer, mostly no higher than the 90s. It was on a diesel Blazer with a 700R4, the factory cooler and a B&M stacked cooler.

I found the radiator cooler to be more consistent in heat removal than the air-to-oil (temp differential and airflow) but I didn't get to test a fan-equipped air-to-oil cooler, which may improve it.

 

[Donald]

I hope you got the transmission flushed, but you could have done it yourself in 30 minutes.

 

[rszappa1]

I would stick to Mopar AFT+4

 

[lewdwig]

+1 the ATF+4