Towing 4-1/2% Grade, WOT, Hot day =......

[DennisG01]

EDIT: Oops... Forgot to mention that the hill was 5 miles long.

220* tranny temp for the first time ever! Now, I wasn't able to get a good running start, so I was stuck in 3rd gear at around 50 - 55mph and the converter never locked. So, I realize that's why the temp probably went so high. I'll check the fluid (and plan on replacing).

I assume it would also be a good idea to drain some fluid out of the pan and look at it?

However, I think I would still feel better if I added an extra tranny cooler. I think I'd like one with a fan. I've found some info on TDP, but there was no "signature" in a lot of the posts - does that mean that particular person is no longer a member here? Because of that I don't know if they had a 4l80E, or not.

I also can't seem to find a website for cooler manufacturer's? In various posts, I came across Long and Tru-Cool, but I can't find their specific website?

I'm rambling a bit here, but basically I'm looking for some guidance on selecting a tranny cooler. Am I correct in thinking that it would better to mount it under the truck (I don't do any off-roading, but will make sure it's above the bottom of the frame)?

Engine coolant temp got a little higher than normal, too (about 215*). But, on a plus side, EGT's never went over 1050*.

I'm also going to check for bugs and crap between things in the grill, although that has always been pretty clean.

[JohnC]

Don't worry...

220 is a little higher than desired, but no problem unless it's day in and day out.

[DennisG01]

Thanks, John. I remember seeing that chart somewhere before - but forgot about it until you posted it. Thanks. That is definitely good to know that it's not as bad as I was thinking.

I'm not seeing 220* all the time, but I think I'd still feel more comfortable with an extra cooler. They don't seem to be all that expensive. I don't know, maybe it's just a "feel good" thing.

[Robyn]

The addition of a remote cooler is the best thing you can do for the tranny.

Myself, I prefer to run the tranny fluid through an air cooler only and not through the radiator at all.

This keeps all that extra heat from the coolant and if you size the cooler big enough you will be able to keep the temp far lower.

If the oil coming from the air cooler goes back through the radiator before it heads back to the tranny it can actually gain some heat.

Go from the tranny through an air cooler and back to the tranny.

Another good idea is to install a remote spin on oil filter inline with the cooler (preferably before the cooler)

The filter will pick up any crap that the tranny generates and get it out of the oil flow (Auto trannies do make quite a bit of crud)

Change the spin on filter every other engine oil change and top off the fluid. This will help extend the life of the tranny a bunch.


Good luck


Robyn

[JohnC]

Keep in mind, though, that in winter, if it gets cold where you are, you will not get TCC lockup or (IIRC) OD unless the temperature is high enough!

Running the trans fluid through the radiator puts a huge load on the cooling system, but it also stabilizes the trans temperature. Maybe the ideal solution is thermostatically controlled bypasses for the two coolers?

[DennisG01]

With my, admittedly, basic knowledge of this subject, I did happen to come across the notion of eliminating the cooler inside the radiator. However, I was leaning towards keeping it due to the issues about TCC lock-up, etc.

BUT, this "thermostatically controlled" idea sounds interesting and I would be open to ideas on this as it sounds like that would do both things: eliminate the cooler in the radiator and also retain cold weather drivability. Would I use something like this?: http://www.summitracing.com/parts/DER-15721/

I also came across this "self-regulating" cooler that apparently uses different sizes of orifices to control the fluid going through the cooler. Supposedly the warmer the fluid gets, the more time it will spend in the cooler: http://www.bulkpart.com/Merchant2/me...de=tru-cool-hd

However, this doesn't have a fan and I'm pretty much set on mounting whatever cooler I get under the truck... correct me if I'm wrong, but I don't think it would be a good idea to mount another hot thing in front of the engine (if there was even room, that is!).

----------

Spin-on filter: Would I be correct in assuming that I would just use a standard remote filter mount? Meaning, this extra tranny filter is the same size as an engine oil filter?

Is the thought behind using this extra filter because it does a better job than the one already in the tranny?

----------

By the way, I do currently have the stock auxiliary cooler mounted in front of the radiator.

[ronniejoe]

I picked up a thermostat for my engine oil cooler from Summit (haven't installed it yet) and am considering one for the transmission as well.

The factory engine oil cooler and trans cooler are too small if you work your truck at all. Back in 2004 while returning from the DP rendezvous, I experienced trans temperatures in the 240 to 260 F range. I didn't have the engine oil temp gauge hooked up yet.

After installing my new engine in 2005, I installed that big DSG engine oil cooler that JK sells and adapted the factory engine oil cooler as my transmission oil cooler (it's a little over twice the size of the factory trans cooler). Here's a picture of the coolers mounted with the grill off:



Since making this change, I have not had any issues with alarming transmission oil temperatures.

However, I am surprised at how hot the engine oil temperature runs even with this larger cooler. Last week, we bought a 2000 GMC Sierra 1500 EC SB 4X4 for my daughter to drive. I trailered it home behind my Suburban. It was about 90F outside that day. Running 75 mph on I-70 Westbound, my engine oil temperature was running about 250 F. This is not unusual at all as it will run around 210 - 220 F running solo. I cannot imagine what the temperatures were with the factory cooler and the extreme egt that the old engine used to run. For this reason, I am considering installing a larger oil pan to get more heat sink capacity and dwell time.

[More Power]

EDIT: Oops... Forgot to mention that the hill was 5 miles long.

220* tranny temp for the first time ever! Now, I wasn't able to get a good running start, so I was stuck in 3rd gear at around 50 - 55mph and the converter never locked. So, I realize that's why the temp probably went so high. I'll check the fluid (and plan on replacing).

I assume it would also be a good idea to drain some fluid out of the pan and look at it?

However, I think I would still feel better if I added an extra tranny cooler. I think I'd like one with a fan. I've found some info on TDP, but there was no "signature" in a lot of the posts - does that mean that particular person is no longer a member here? Because of that I don't know if they had a 4l80E, or not.

I also can't seem to find a website for cooler manufacturer's? In various posts, I came across Long and Tru-Cool, but I can't find their specific website?

I'm rambling a bit here, but basically I'm looking for some guidance on selecting a tranny cooler. Am I correct in thinking that it would better to mount it under the truck (I don't do any off-roading, but will make sure it's above the bottom of the frame)?

Engine coolant temp got a little higher than normal, too (about 215*). But, on a plus side, EGT's never went over 1050*.

I'm also going to check for bugs and crap between things in the grill, although that has always been pretty clean.

Dennis,

Lots of good info here.

I'll add to it by relating what member Tom McCauley learned back in the 1990's with his 6.5TD Suburban, which he used to tow a large travel-trailer. As I recall, his Suburban eventually ran with three transmission coolers - the original in-rad cooler, a large air/oil cooler mounted ahead of the cooler stack (behind the grille)and a large B&M thermostatically-controlled fan-cooled cooler located beneath the chassis. This last fan-cooled B&M cooler made the most significant improvement in reducing transmission temperatures - as I recall.

Jim

[DennisG01]

Excellent, excellent info, guys. Thank you very much.

Ron, that's good idea about swapping auxiliary coolers - that never even crossed my mind.

I misunderstood "thermostatically" when it was first mentioned. I thought it was only in relation to turning the fan on/off. If I understand correctly, the idea is that it actually uses a thermostat to either allow fluid to go through or to bypass?

If I go the "under truck" mount way, it wouldn't hurt anything to get the biggest one I can, would it?

EDIT: Also, does it matter whether I go with a tube/fin or stacked plate? Or, is it sort of "six of one, half dozen of the other"? I'm researching this the best I can, but I keep coming up with varying positions. I'm lost!

Does anyone know what size the return line fitting to the tranny is?

[Kennedy]

My 96 had an option "Aux transmission cooler" added or something to that effect. I still have the window sticker here.

Anyhow this cooler was a 3rd tube/fin cooler behind the rad and it really worked well. I never had trans temp issues even pre KD fan clutch days when the engine ran hot.

Keep the in tank cooler. It does more for you than the other coolers do.

[DennisG01]

Still working on this...

The only company I've been able to actually find a phone number for and talk to is B&M. They recommended not using a cooler with a fan on it mounted under the truck as it still wouldn't get enough air to be efficient.

They recommended going to a bigger auxiliary cooler (replacing the one that is currently in front of the radiator. This one is rated for 29K BTU: http://www.bmracing.com/PRODUCTS/Uni...TU-11x11x1-1-2

Any thoughts? Does that sound reasonable?

[joed]

We installed one of these on my dad's 95 in place of the stock trans cooler. Seems to help keep temps cooler.

I got it from bulkpart: http://www.bulkpart.com/Merchant2/me...e=tru-cool-ind

You should be able to save some $ - I believe Long mfg makes all these coolers, just under different brands.

That particular unit is an oil cooler (has 1/2" fittings) - you'll have to use a 3/8 (I think that's stock, if I remember) to 1/2 adapter.

One thing to verify, if you haven't already, is that your fan clutch is working. Still need that to help pull the air through it.

Hope that helps.

[DennisG01]

Joe, that does help. I bet you're right about Long making all of them. The bigger one in your link has the exact same dimensions and BTU rating as the B&M (which I found at Summit for $89).