I've heard Scotty mention before that it's bad for a transmission if you drive through water or flooding roads, question is with a pickup truck that has off road capability is there some sort of protection built in? My tacoma is the SR base model with 4x4 6 speed automatic transmission.
there are a number of things you need to consider when driving through deep water
Engine
If the engine ingests enough water, then you can kiss it goodbye. Be aware of where your air intake is.
It's best to avoid it, but people who need to cross deep water often get snorkel kits.
Drivetrain
All your drivetrain components (transmission, transfer case, axles) are vented to the atmosphere. Be aware of where the vents are. Water contamination will destroy them in short order. The hoses can be extended. Inspect often.
Chassis
water will significantly shorten the life of wheel and axle bearings. If you plan to ford water often, then replace with SEALED bearings.
Electrical
Obviously they don't mix. I don't know what to tell you about this one. Keep your PCM and other modules OUT of the water. Inspect connectors often, and pack with dielectric grease I guess.
Body
Remove plugs, drill drain holes, or do whatever is necessary to keep water from pooling up in the frame and bodywork.
Since I live in Maine and they salt the roads heavily in the winter I pressure wash the underbody frequently, I can't imagine the water would get into the transmission from doing that....
I can imagine it. All it takes is for one ounce of water to destroy the clutches and gaskets.
All you have to do is find your transmission vent and be mindful of it. No big deal.
I think the transmission vent is under the hood in the engine bay from what I've read online but I don't know I'm not a mechanic BUT I drove a 2014 Subaru legacy before I got the Tacoma and I pressure washed the engine bay and underbody of that car several times a year with no problems. Local mechanic said it was fine just don't spray water into the air intake.
OK, I thought this question was about fording deep water.
The vent should be close to the highest point on the transmission. I would be more worried about the axles though, since they sit lower.
I think driving through flooded roads is something that should be avoided at all costs.
You have no idea how deep it is, the road could be washed out, your vehicle could lift up and be carried away, etc.
In addition to water possibly entering your transmission, your differentials can also take on water, and would need to be drained and refilled.
Check out this site:
https://www.tacomaworld.com/threads/how-deep-of-water-would-you-go-with-a-stock-tacoma.490413/
Check your owners manual for a section called driving hints or driving through water. It will probably say not to drive in water that is deeper than the hubs.
Your built in protection is the ground clearance of the vehicle. That's it.
I wouldn't recommend it.
If it's not a boat, don't drive it through water...
