Hi all, Am having transmission cooling problems with my manualised th400 and looking for some advice. Currently using the largest derale 10" x 17" cooler but does not seem to be up to the task in race conditions. I've seen people use auto airconditioner radiators with fans, and other who use multiple oil coolers but would like to hear what other people have had success with for trans cooling. Cheers Bert
Firstly whatever cooler you plan to use you will need a fan.
I have used an airconditioner radiator in the past and t worked well, the issue with them is they are not designed for the abuse of offroad and all the fittings are slip on hoses which can come off. They are also not teh best looking.
I now have 2 x Large Transcoolers with a fan on each, I have on run the car once and that was just testing but it seems to be working well.
I have attached a picture of my setup. These were not that expensive the coolers are Long Tur-Coolers 10"x11" about $70.00 on ebay from Race Basics and the rest I made up.
I'm using a dominator convertor with about 1700 rpm stall. Thanks for the pics Jason, that's the sort of advice I was after, very neat set up. I have also been told to use synthetic trans oil. Would this run cooler or simply last longer under race conditions?
I know of one car that uses a gearoil pump drawing out of the trans sump and pumping through a cooler as a secondary cooling system as well as the main cooling system circulated by trans pressure. Tilton make a pump and so does Albins
bert before you invest money in exotic oil or complicated plumbing get a proper diagnosis on your box by a professional,you may save hundreds if not a couple of thousand if it is only a simple problem now.if it was me i would remove the pan and check it for contaminants eg metal etc,and check oilpickup screen for blockage.
I personally have not used any synthetic trans oils, I just use good old fashioned F-Type fluid as I run a Ford C4. Beeker is correct with regard to your stall the higher the stall the more heat it will generate. I run a 2200 rpm stall in mine and so far this setup is working fine. I also have a larger capacity alloy pan which would also help. As yours is a Turbo 400 Dexron should be fine.
Aztek run's a T400 with a similar cooler setup you could ask him what fluid he uses.
With regards to Beekers point on getting a Professional to look at your tranny no matter what they find you will need the exotic coolers and plumbing. Offroading cause so much heat to be generated in an automatic tranny and it wouldn't matter what componenets are installed in the box if you can't dissapate the heat it will lead to premature failure.
As far as I am informed, synthetic fluid does not make the tranny run cooler, but does handle hotter temps before breaking down (the oil that is)...but if the box is overheated the oil does not recover and should be flushed. So I would suggest getting any issues sorted with cheap mineral oils, then later flushing and replacing with synthetic for longer tranny life. I believe that the small coolers such as 568 suggested will not handle long course events (sorry, hope I am wrong), and I also believe Azteks runs too hot, but he does'nt have an accurate guage. Stall speeds make a HUGE difference, so run as low as possible! I suggest running as big as possible PWR cooler or similar, and possible extra pump. I know its expensive, but probably the only way it can be done successfully!
I just took a look at the PWR site and there largest Trans cooler complete with fan ( No cowling therefore not all teh air is drawn through the cooler) is 280mm (11") x 255 (9.8") x 19mm (3/4) thick (Part # PWO1223SP). They are almost exactly the same dimensions as my coolers only difference is mine are 1" thick and $200 less each.
If your going to buy a purpose built cooler you would look at the fluiddyne trans coolers but they are mega bucks. There on page 83 of the McKenzies catalog Dimensions are 15" x 15" x 9" (9" inches thick which means that it is a multipass cooler).
1700 stall is not really a huge stall or 2200 for that matter,i assume that they are 12inch converters which hold a large quantity of oil.one other thing that should be checked is that the oil level is correct,if it is to low we all know what happens there but if it is over full the oil will have contact with the rotating assemblies which will airrate the oil which will have severe affects on your box.make sure your dipstick is correct etc.
I had some overheating issues (mainly in the sand at finke) and found that the majority was caused by the torque convertor...not only did reducing the stall help, but the clutch was slipping, once repaired it dropped by 40 deg C, without modifying my coolers.(dropped from 2300 to 1700 stall) Also the cooler size is not necessarily related to efficiency, apparently its the flow inside the tubes and the restriction for heat dissipation thats important, hence why an AC condensor is not the best. Although there are some clever people in aussie, I would suggest talking to some of the yanks...if they can keep cool in Baja, then they might have some good advice. Looking through some of their magazines, they have huge coolers...and unfortunately, priced to match! My coolers are probably 2-3 times the size of 568(and proffessionally made), and I am thinking of adding another. Lets not forget I am not running 400hp in 2 tons of car either (more like 160hp and 1.3 ton). You can never be too cool:) Sorry beeker, but in off-road and temp terms, 2200 stall is fairly high and will generate huge heat!
Intresting reading of different ideas. From what i have learnt most class 4 trucks run a stall around the 3000 mark which we run. Derale oil cooler are just not big enough there large size is a 16pass i think, we use a 32pass cooler coupled to twin thremo fans. Our oil system hold 13litres (castol Trans max z) for us the only one to use and will drop the temp by around 5-10deg and runs around 180-200 all day long.
2200 stall is not big at all,if you are driving under that stall speed you must be driving very slow or not correctly,it would be like driving a manual with your foot half on the clutch,or your camshaft,stall,final drive ratio is up to shit
With regard to stall converters don't forget there original name they are torque convertes now something I didn't know until late last year when I was looking to changing my converter is that the stall speed is affected greatly by how much torque yoru engine produces and how heavy the car is and its diff ratio.
Here's a quote from car craft magazine: "Of course, the power and torque curves of your motor will have a huge effect on stall speed. Generally speaking, engines that produce more low-end torque will bump the stall speed to a higher rpm. Conversely, the same converter will stall to a lower rpm behind a less torquey, higher-winding engine. Converter companies often designate the former as big-block and the latter small-block. When you buy a typical converter thats rated at 2,000-2,500-rpm stall, that rating is meant to span a variety of motors with different power curves. Scott Miller of TCI points out his companys 12-inch Saturday Night Special converters typically stall at 1,600-1,800 rpm behind a 325-375 lb-ft small-block and up to 2,000 rpm behind a 400-450 lb-ft big-block. Sure, theyll stall even higher behind a torquier motor, but theyre intended for mild, conservatively cammed motors"
Therefore the numbers we are all banting about aren't that accurate unless you know how much torque your engines producing. More torque hihger stall more heat argh!!!
Jason not to take sides or bat about the size of it, from your quote i can assume that you have bought a off the shelf stall converter and some of these are not very efficent. also the quote reads for mild camed motors. So if this is the case our motor probably if just comming on song when your power curve is about to peak. So to keep our engine in its power range we require a lot higher stall. Now if you have your engine dynoed before it goes in the car you would have data which a custom stall can be desgined to suit that engine making an accuate stall rate. You seem to be very worried about heat yes bigger stall more heat but if you stay over the stall speed stall size is not an issue. last if your final drive ratio is correct which uses the compete power range of the engine this will also help in keeping the gearbox cooler. All this is just my opion and which works for us . I agreee beeker real men do it on the dirt be a man and come and have a go.
Almighty I don't disagree with anything you've said. I am fairly confident that I have my trans cooling sorted. I will let you all know after Nabiac as the sandy sections on that track can be murder on a tranny.
Just another point regarding heat in a transmission some of the shift kits have been know to play a part in excessive heat being generated in a transmission where as a new valve body such as a Art Carr are much better and tend not to helo keep things cool. This is based on past experience and trial and error.
Sorry Guys I'm a little late on this one....mainly because I have no idea about autos...or anything else for that matter!
Jones is right, I have a very simmilar set up to Jasons and I do have some over heating problems, mainly on tight twisty tracks when using 1st and 2nd gears (just as Beeker suggests) however the trans has been in the car since I built it over 4yrs ago, and although I know I haven't done as many miles as I would have liked, we have had no problems......untill this weekend at Crookwell it has developed a bit of slip in 2nd gear...which I guess could be heat related?
Dont let bands fool you, they are rarely the reason auto trannies have problems. The old saying 'the bands need adjustment' is simply untrue in most circumstances...its almost always a clutch problem. Sorry 568, but I think that the sand a nabiac is not a good indicator of how your oil temp will go, you really need to do long distances to know for sure....I found that my overheating (now known to be a torque convertor problem) would take about 200km of constant driving! The temp would fluctuate according to conditions (ie sand, slow/high speeds), but would always be on an upward spiral. Almighty is right about the atf, I heard it can handle temps of up to 240 deg before breaking down. But I think its very expensive (approx $300/20ltr?), so thats why I think any cooling/trans issues would be best sorted before using it. Everything everyone has said is correct in some form, unsure if beeker is talking about off-road cars or road cars, but if he is refering to road used vehicles, then none of that can be related to our use. Hope your not too confused bert!!
Jones I have to concede , after this weekends testing it became evident that the box is getting a little to hot. After about 2 hours I lost 2nd gear which maybe a result of that, havent stripped it down yet. However I ran the rest of the day using 1st and 3rd and it didn't get any worse.
I am now considering plumbing in a water to oil heat exchanger to assit the coolers up the back, has anybody tried this and how did you go? Apparently water to oil is far more efficient than air to oil cooler.
Sorry about that 568, I had two (really expensive) oil heat exchangers that came with my old stadium truck (Chris Huttons now). A few of us looked at using them, but the plumbing would have been a nightmare (and possibly unreliable). And they were very heavy, in case you worry about weight. I think air/oil coolers would be fine, as long as the right ones are used. Possibly ring Gavin Mickle (micklefab), as we were talking about this issue the other night and he seems to have some nice set-ups!
Solved my cooling problems with help from Almighty. I used a airconditioner condensor of dimensions 26" x 15" and is a 32 pass unit purchased on ebay for $1 (definitely cheaper than other cooler options) I run twin thermo fans and transmax z fluid and has not looked like getting hot. Thanks all
, after this weekends testing it became evident that the box is getting a little to hot. After about 2 hours I lost 2nd gear which maybe a result of that
, havent stripped it down yet. However I ran the rest of the day using 1st and 3rd and it didn't get any worse.
