Towing, Tranny Temps, and Coolers

PNW yota

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So I recently bought a small toy hauler. Dry weight 3200. After bikes, food, 40 gallons of water ect. I'm guessing I'm towing somewhere around 4500 pounds. I have an external cooler and a trans temp gauge.

When pulling the pass at 25 mph, locked into 1st, 4wd engaged, overdrive off, ECT on and an ambient air temp in the 20's- my trans temp was around 230.

When towing at 60 mph on flat grade with overdrive off and ECT on in 2wd it stays around 150-160.

Without towing it's around 130.

Does anyone know what the max temp rating is for the transmission before it starts melting o-rings? I'm not interested in guesses, so if you don't know the answer please don't throw out a guess.

Next I'm wondering if anyone has a trans cooler that fits the full width of the radiator. I have an external that is only a 2 pass that covers half the width of the radiator. I'm guessing 230 is too hot and plan to install a larger cooler with more passes and figure I might as well fill the space in front of the radiator.

Thanks for the help and please no guesses on the temp.
 
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Which external trans cooler are you using?

I am running a B&M 70274 rated at 29,200 btu and it keeps my 4Runner cool. I'm towing about 2500 pounds so much lighter load but it's in 105+ degree heat, 4lo, dragging my trailer through deep sand moving around 10 mph or slower and my 4Runner is on 285's. I will sometimes see temps up to 200 and one time I got stuck it went up to 210, but not for more than a couple minutes before it came back down. Even pulling hills in AZ on freeway in 2wd and 112+ degree heat I'd never get over 190. Biggest difference between us is weight. Here's a link to the cooler I have and pics of my trans cooler set up.

*notes: I had to remove black center bar that runs vertically and attaches to the core support. This bar is also where the center clip of the grill attaches. This also means I had to ditch the center clip on my grill and this has made zero difference for me.
Actual Cooler core measurements: 11.25x11.5x1.5 its as thick as you can go and still get your grill to attach properly

B&M 70274, B&M SuperCooler Transmission Coolers | B&M - Free Shipping on All Orders @ JEGS
 

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I was running a Derale 13104 7000 series 18 1/2 x 13 which was the biggest size I could fit. Because of my driving conditions ( always under 35, tropical weather, steep windy roads) my torque convertor never locked up much and on sunny days behind a slow tourist I would hit 220. Under the conditions you were driving I do not think any stand alone transmission cooler is going to work. The cheapest and easiest fix is to buy a new radiator and run it through the transmission cooler you have first. Others have put in electric fan systems to keep it cool. I ended up swapping the trans to a 5 speed and I never think about it now.
 
I was running a Derale 13104 7000 series 18 1/2 x 13 which was the biggest size I could fit. Because of my driving conditions ( always under 35, tropical weather, steep windy roads) my torque convertor never locked up much and on sunny days behind a slow tourist I would hit 220. Under the conditions you were driving I do not think any stand alone transmission cooler is going to work. The cheapest and easiest fix is to buy a new radiator and run it through the transmission cooler you have first. Others have put in electric fan systems to keep it cool. I ended up swapping the trans to a 5 speed and I never think about it now.

I'll look into that cooler. The one pictured on amazon is an 8 pass. It would be a huge improvement over what I have. If a larger cooler doesn't work I'll probably go with a larger pan.
 
Any reason why B&M is twice the price of Derale? I'm more than willing to pay up for quality but not for a brand name...
 
cooler

Try ford escape transmission cooler: about 18 inches long and 5-6 inches wide.
This should fit at the lower valence opening
 

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Any reason why B&M is twice the price of Derale? I'm more than willing to pay up for quality but not for a brand name...

Not sure. It was installed by the previous owner. It appears to be plate style and it measures 7x11x0.75.

Derale 7000 series use a tube and fin style cooler versus the derale 9000 series a plate and fin style and then the Derale 10000 series and my B&M uses an even more efficient stacked plate and fin. The stacked plate and fin is more efficient and cools better than tube and fin, I will leave you to google if you want a more scientific answer lol. When you look at Derale 9000 series, the model Derale 13614 is the closest in comparison I could find to the B&M 70274 I have regarding size, but it is still thinner. I can't find exact GVW for B&M, but the derale 9000 I posted is rated at 22,000 GVW. According to one web site I found, the B&M 70264 measuring 5.75x11x1.5 is rated at 24,000 GVW. When we look at Derale 10000 series, it actually has a higher BTU rating than the B&M, the Derale 13402 handles 32,000 BTU and the 13403 handles 37,000 but to B&M's 29,200 BTU. The difference being that the Derale is even thicker than B&M. I'd say the biggest downfall to your cooler is sheer size. As for money, the Derale 10000 series is similar in price to the B&M, on Amazon the 13402 can be had for $112 and 13403 can be had for $125.

Derale 9000 13614: Series 9000 Plate & Fin : 17 Row Series 9000 Plate & Fin Transmission Cooler Kit

Specifications •Cooler style: Plate & Fin
•Construction: Aluminum
•Inlet size: 1/2" NPT female
•Fitting size: 3/8" barb
•GVW: 24000
•Width: 10-1/8"
•Height: 11-7/8"
•Depth: 1-1/4"
•Inlet dim: 8-7/8"
•Mounting: 6-3/4" x 10-1/2"
•Hose size: 3/8"
•Hose length: 4'

Features •Prevents heat related transmission failures
•Extends life of transmission
•Improves transmission performance
•Sturdy furnace-brazed aluminum construction
•17 row cooler design
•1-1/4" turbulators maximize cooling & minimize pressure drop
•1/2" NPT female cooler fittings
•1/2" NPT x 3/8" hose barb adapters included
•22500 GVW rated
•Fluid Capacity: 12 oz.

Derale 10000 13402: http://derale.com/products/fluid-co...1-2-npt-ports-and-3-4-16-filter-thread-detail

Description

With our top of the line 16 Row Stack Plate cooler, -6AN aluminum fittings and hose barb adapters, this highly efficient kit extends transmission life by preventing heat-related transmission failures while also improving shifting performance. This kit comes with a complete transmission cooler hardware kit to easily install onto vehicles with 5/16" transmission cooler lines.


Specifications •Cooler style: Stacked Plate
•Construction: Aluminum
•Inlet size: -10AN o-ring female x -6AN male
•Fitting size: 3/8" barb
•Width: 13"
•Height: 6-7/16"
•Depth: 2"
•Inlet dim: 10"
•Mounting: 12-1/4" x 4-7/8"
•Hose size: 3/8"
•Hose length: 4'
•32,000 BTU's Per Hour

Features •Built in turbulators agitate fluid for maximum heat transfer
•Sturdy furnace brazed all aluminum construction tested to 250 p.s.i.
•16 row cooler design
•Male -6AN aluminum O-ring inlet fittings & 3/8" hose barb adapters included
•Complete hardware kit included
•32,000 BTU's Per Hour



B&M 70274: B&M Oil Cooler, Supercooler Large, NPT Fittings, Plate Type, Black » B&M

Dimensions 11 x 11 x 1-12
Features B&M Super Coolers are 100% aluminum stacked plate style core which is ideal for additional transmission cooling. With oven brazed construction this sturdy cooler design is practically impervious to flying rocks or other debris. •Better Than Ordinary Cooler
•Resistant To Damage
•Rigid Stacked-Plate Design
•Small Size and Lightweight



Product Attributes


Depth (in):
1.50
Inlet Size:
1/2 NPT

Outlet Size:
1/2 NPT
Width (in):
11.50

Height (in):
13.00
Row Quanity:
45

Material:
Aluminum
Title:
B&M® 70274 Cooler, Supercooler Large, NPT Fittings, Plate Type, Black

Package Contents:
Cooler
Inlet Attachment Type:
Female Threads

Outlet Attachment Type:
Female Threads
Low Temperature Bypass:
No

Design Type:
Stacked Plate design
 
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I went and looked to see if you could fit a 2" thick cooler in there and you certainly can. You will just have to trim the bottom center grill clip back a bit and you will have to remove the center bar that holds one of the A/C lines, but for the load you're pulling, it will be worth it to get one of those monster derale 10000 series.

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No offense intended but I wouldn't tow that weight over a pass, it will be a very short remaining life. I mean really, 230 degrees in 20 degree weather! What will it reach in summer?? Despite that, Good Luck. :cowboy:
 
Did you bypass your cooler in the Rad? Or is your external cooler in series? I have the TrueCool 4589. It was big enough it was difficult to mount. Rated at 21,000 BTU.

Like mentioned above for your situation having the Rad trans cooler in series with a large external stacked Fin and Plate would be the best you could do. Other than installing a switch to lock up the Torque Converter and eliminate the heat.

And filling trans with Synthetic Dex3.
 
I went and looked to see if you could fit a 2" thick cooler in there and you certainly can. You will just have to trim the bottom center grill clip back a bit and you will have to remove the center bar that holds one of the A/C lines, but for the load you're pulling, it will be worth it to get one of those monster derale 10000 series.

I think I can get the Derale 10000 series 13403 to fit, seems to be the stoutest. Might take some cutting :flamethrwoer2:

If that doesn't work I guess I'll have to look into a different tow rig. Problem will be convincing the wife we need a third vehicle!
 
Did you bypass your cooler in the Rad? Or is your external cooler in series? I have the TrueCool 4589. It was big enough it was difficult to mount. Rated at 21,000 BTU.

Like mentioned above for your situation having the Rad trans cooler in series with a large external stacked Fin and Plate would be the best you could do. Other than installing a switch to lock up the Torque Converter and eliminate the heat.

And filling trans with Synthetic Dex3.

Trans cooler is isolated to avoid the milkshake in the radiator. If I replace the Rad down the road I might hook things back up in series.

I just had the transmission serviced last month at Toyota and I'm trying to find out what kind of fluid they put in. If it's not synthetic I'll be dumping it.
 
Mobile 1 makes a synthetic Dex3. Pennzoil Multi Vehicle is a synthetic Dex3 also.

A push button switch that latches in a relay through the brake light switch to energize the TCC would do wonders for you. Depressing the brake pedal would turn it off until you press the lockup button again. Could also use it as a hill decent.
 

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