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Transmission oil coolers

Calaber

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I'd like some info from members of the forum who have fitted transmission oil coolers to their cars.

My Captiva has a five speed auto which works well under most conditions but has a nasty little habit when you are required to shift from forward to reverse and back again once the trans gets hot.

If you have been driving for a while and need to park, which involves a number of shifts between forward and reverse, the trans will not immediately pick up the chosen gear. The engine will idle for a second or two then the trans thumps into the chosen ratio. I'm assuming it's partly because the trans is worn (165k) and also because the oil has heated up and is thinned out due to heat. I'm considering an external oil cooler for the trans to see if that reduces this annoying habit. The car is only occasionally used to tow a box trailer to the dump - no heavy towing is involved.

My questions are:

1. Has anybody else experienced similar behaviour to my auto when the transmission oil cooling system only involves the standard heat exchanger in the radiator?
2. Did fitting an external cooler reduce or eliminate this behaviour?
3. Are there any other benefits you can think of that you have found after fitting one of these coolers?
4. Is there any particular brand you would recommend, and what is the approx. cost?
5. Does an external cooler completely replace the heat exchanger or is it fitted in sequence, so that the oil passes through both the cooler and the heat exchanger?
6. Finally, any problems encountered with an external cooler?
 

immortality

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I'm not familiar with the Captiva transmission (driven one once, wasn't impressed) but how are the other gears when the transmission is hot? Has it ever had the transmission fluid changed?

IF it's a bit clunky in the other gears it would be a good indication that it's in need of a full service flush/new fluid.

Has it always done this or only started since the mileage is starting to get up there. There will be over-heat protection for the transmission in the tune, whether or not that is causing your issues is only a guess.

I only can't see an extra external cooler effecting the transmission. Generally external transmission coolers are fitted in-line (after) the internal radiator transmission cooler. Definitely good insurance if your ever doing any towing.
 

VR38

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In any event the car, under normal conditions, should perform as per it should, fitting a trans cooler to fix something will only be a band aid cure.

Suggests getting a service and a quote on what maybe the problem, if the service does not fix it.
 

immortality

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External transmission coolers are normally fitted as part of a towing package.
 

Deuce

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I installed a trans cooler on my car,
front view.jpgbehind bumper.jpg
And I found that my engine temp gauge consistently sat 1/3 of a section lower.

My tran's is kitted though, so am not sure if it would show similar effects on a stock set up.
 

Calaber

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Hmm, yeah, well I forgot to mention that it had a complete oil change, not just a "service", about 30k ago. The old oil was filthy as it was probably the original and would have done over 130k.

I've had the car for about fifteen months and it had this problem since I bought it. (Naturally, it didn't occur during the test drive.) As the problem only occurs after the car has been driven for a distance, I suspect the oil thins out as its temperature rises and due to wear in the trans, there is something not working as it should. In all other respects, the trans is good. My feeling was that by keeping the trans oil cooler, this problem might be abated.
 

ari666

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hmmmm, well they are reasonably cheap and easy to fit, so i suppose if you have a spare 70 bucks and a free afternoon, i suppose it couldnt hurt:
High Performance Transmission Oil Coolers

ive fitted a few before, but only ever as "fix a problem before it becomes a problem" kinda things. so i couldnt comment on a before and after.

edit* to answer question 5. its to be used in conjuntion with the radiator cooler. they are just an aid, not a replacement.

fitment can be tricky, the kit i linked comes with long zip ties that go through the rad and the cooler to be mounted directly to it, but ive been instructed by numerous people to always fit them with at least a 2 inch gap between it and the rad. they do deflect a lot of air, so the gap allows the thermo fans to still drawn in cool air while in traffic.

also you get what you paid for, there are shorter/fatter units which are much more effective, but the cost increases.
http://vpw.com.au/Category/Index/400187
 

Pollushon

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I'll refer to a post I made here: http://forums.justcommodores.com.au...-1997/220369-external-transmssion-cooler.html

I grabbed one of those PWR ones (the smaller 280 x 200 x 19mm) and put it in this Saturday gone, so far so good, it's a high quality piece of stacked plate kit. Comparatively the stock VS trans cooler is a heap of snot. Currently running an experiment bypassing the rad cooler but I have the cooler mounted against the radiator core using nylon mounts and thermal tape all round (which also cushions metal on metal) using an NTC sensor from work to monitor the temps in the centre and it's comfortably hovering around 75/80c. Reaches this temp as the engine reaches op temp.

The issue I've always had with fluid warming via the Commodore cooling system is the high pressure set-up sees the water temp (and therefore the rad temp) at 93 - 100c during normal operation. The traditional Holden trans cooler setup goes to the external cooler and then back to the rad then to the trans, so in some situations it negates any value-add the cooler has, 100c is just too hot for a poor 4L60E. Hell Holden didn't fix it's hapless cooling designs til the recent (2008?) VE redesign rad and fan system borrowed from others who shed light on the path. Also, since the blower went on my trans is seeing a lot more stress then before.

Not saying you should do what I'm doing, it is an experiment and if my trans goes pop it just means I'll have a manual in sooner than expected. That said I am surprised at the results so far and the tranny does seem to be a lot happier especially around TC lockups. Changing the fluid this weekend, fingers crossed I'll get more than 20k out of this batch before it's done.
Nearly two months now and still, so far so good. I actually didn't change the fluid as planned, but am hoping to check it out this weekend when I drop my oil.

Ari the air deflection isn't an issue with a decent stacked plate like the PWR, the thing is almost invisible.
 
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