I have a 1989 Cat 426 backhoe that is somehow getting water in the transmission. I changed the transmission fluid today and it is milky looking. There is no signs of oil in the radiator though but water level was a little low. I'm guessing that my transmission cooler has gone bad. It appears the transmission cooler is inside the bottom portion of the radiator by following the hydraulic lines from the transmission. Are these things repairable or am I looking at possibly having to buy a whole new radiator? I can't see how you could repair the cooler part since it looks like it is internally inside the radiator without access unless the radiator was cut open. Would I have to buy another Cat radiator or would one from another brand of backhoe work? I'm finding out that these Series 1 Cat 426 hoe parts espicially used are not that plentiful. There is still a slight chance the water entered by other means since we have had heavy rain 5 days in a row last week here in North Carolina but I'm not holding my breath on that. Any help would be appreciated. Thanks.
A radiator shop may be able to crack it open and see what's going on. There could be some 3rd party one that would work as a replacement, and almost anything can be made to fit with enough fabrication and cursing, though I'd go with a more 'proper' cooler setup if that were the case. A plain radiator for coolant and then a smaller oil cooler for the trans. One thing you could do as a cheap, but effective, stop gap, or for years and years even, is to just remove the trans cooler lines from the radiator and flush that part of it out good, in case there is some kind of crack in there allowing cross contamination, then cap them off and just mount yourself an external trans cooler in front of the radiator. That way you'll at least have the radiator eliminated from allowing any coolant to get in there, and if the radiator does in fact leak into the oil cooler portion of it no real biggie as it's capped off.
I like the idea of just capping off the radiator and installing an external cooler in front of the radiator. Not sure of the volume of transmission fluid going through the old cooler but imagine that will be key in sizing up an external cooler. Wondering if a transmission cooler from a pickup truck would be big enough? Any ideas?
Okay, first thing to do is be sure the "water" in the transmission is or isn't coming from the radiator! Two ways to determine that. First would be to take an oil sample and have it tested. Second may sound disgusting but it can be done onsite and without any special tooling. When there is moisture of any kind in an oil system there is almost always some "slime" on the filler cap. Stick the tip of your finger in that "slime" and touch it to the tip of your tongue. If it has a sweet taste to it you have a coolant leak. If you are not 100% sure stick finger in top of radiator and repeat so you know what coolant tastes like! Note I said taste not drink a quart of the stuff it is poison! Helps to have some strong coffee to rinse out the taste and spit it out.
You obviously don't want to undersize it, and measuring how much the internal one holds for comparison would most likely do that. Being it's a built in cooler means it will typically hold less oil than an external one does, as it's technically being liquid/air cooled versus just straight air cooled, so you'll end up with a little higher trans oil capacity when doing that conversion, but that's not going to hurt anything. Any decent sized oil/trans cooler should do the job, then just keep an eye on the trans fluid level and adjust it accordingly, as well as the temp gauges if it has them to make sure the trans fluid isn't getting too hot and the radiator isn't being restricted too much. Probably wouldn't hurt to just give the fins a good cleaning also out while you're in there.
Since this is an 89, if it doesn't have working AC then you're not likely to work it that hard, right? If this is a hobby/homeowner machine then the cooler can be bypassed as long as you keep that in mind. If you go to the trouble of adding an air cooled transmission cooler, try to get one off of heavy equipment if possible, it will be heavier built with wider fin spacing so it won't flatten and plug the fins as easily as a typical automotive cooler.
Yes, this is strictly a Farm / Homeowner backhoe. Probably 90% of it use will be digging and moving dirt with the rear bucket. Am I ok to presume that the transmission should only get hot when and if pushing dirt with the front bucket or driving forward or reverse for long distances?
Yes, that's my guess. But first figure out if it's rainwater or coolant. If you don't like Khansen's idea of tasting the foam, you can drip it onto a hot 300 degree piece of steel and smell it. Drip a sample of oil, and one of antifreeze if you're not sure what you're smelling.
Well then! I guess you could go that route! Burning antifreeze does have a very distinctive aroma! It's not like I said to drink a cupful of the stuff
I'm too wimpy to taste fluids on purpose but I have gotten my fair share of splashes in the face. That said, I got some "embittered" antifreeze in my mouth the other day. Like one drop from a tiny splash. They were not kidding about the bitter. It just about killed me until I could get it rinsed out with tons of water.
Thanks for everyones help. I will keep close watch on the trans fluid to see if it starts getting milky again. Ran it for a couple hours today and so far fluid looks fine. Calling for chance of rain tomorrow and this weekend so we'll see how it goes.
If you had enough coolant to make it milky ,you should be able to smell it.
Something to be aware of, too big a cooler could result in cold trans fluid. Trans works best when hot, so don't get carried away. Recommended procedure for adding a trans cooler to a vehicle that needs more cooling for towing or whatever is to run the fluid through the external cooler and then through the radiator cooler to bring the fluid up to temp. Joe H
Check The rubber boot around gear shift lever where it goes into the trans, the rubber breaks down most of it is probably gone or full of holes