Looking at my transmission cooler's rusted exterior I have terrifying thoughts about things failing internally and the coolant and trans fluid mixing. I was looking for anecodtes from people who:
Lost a trans cooler and had coolant and trans fluid mix. How bad and costly was the damage in real dollars?
Has anyone replaced a trans cooler as preventative maintenance? This idea looks less and less absurd to me every day and it looks really easy to get out. I wonder what the heat exchanger costs though. Hopefully less than $1K.
Check Roland's old posts. His failed and the coolant mixed with tranny fluid. Bad cocktail.
Failed Transmission cooler (http://www.foreforums.com/index.php?topic=24602.msg193018#msg193018)
Pierce
The trans cooler works the same as an engine oil cooler. If you keep your coolant maintained there will not be corrosion internally. The only failures I have encountered were when coolant did not have rust inhibitors or proper mix of glycol.
Not all of us have maintenance records for coolant type or when it was changed by the previous owner(s). Since we drive diesel pushers, winter road spray may also effect the longevity of the cooler. Also, all Foretravels don't have the same design, materials or location of the cooler. Good to contact Roland for the coach maintenance history, mileage, cost of repair, etc.
An air to air cooler could be fitted with fan. This would be much like a turbo intercooler but smaller. With the transmission in lockup, there is not that much heat generated since there is no torque converter slippage. Our transmission temperature is far higher in city driving where we we get a lot of start and stop cycles in first and lower second gear.
Pierce
When there is surface rust on tranny cooler, we recommend spraying with Loctite Extend rust protector. We us Extend on oil pan and all metal with surface rust. Do not remove surface rust prior to spraying Extend.
Thanks I have a can of that. I'll add it to my list.
Would Corrosion X do any good for removing the surface rust and sealing the surface prior to Extend?
Trent
Another great and dirt cheap product that I have been using on rust is OSPHO or POR15. Just spray on and let dry then paint away.
JohnH
A $20 HF handheld spot blaster filled with soda will clean it like new, washes off without residue and then can be painted with the user's favorite. The onboard air compressor will supply enough PSI/CFMs to do the job on this small part. Filled with soda, it can be used around mechanical/electrical devices without fear of contamination like sand would do.
21 Oz. Hopper Gravity Feed Spot Blaster Gun (http://www.harborfreight.com/21-oz-hopper-gravity-feed-spot-blaster-gun-95793.html)
50 lbs of soda: Soda Blasting Media - 50 Lbs. Medium Grade (http://www.harborfreight.com/50-lbs-medium-grade-armex-soda-blast-media-65929.html)
Pierce
Extend only works on rust and stops rust. Spraying CorrosionX negates Extend.