Shared vs independent brake and clutch reservoir

I've just recently learned that TRD Sport Tacomas with manual transmission share a reservoir with the brakes, whereas TRD Offroad and Pro Tacomas with manual transmission have independent reservoirs for both the brakes and clutch. I'm hoping to learn about any technical pros/cons of each configuration. I'm assuming there are downsides to sharing a reservoir, or rather there are benefits to the clutch having it's own reservoir. I wheel my TRD Sport in 4Lo often, and when I do the clutch is either fully in when stopped, or fully out when moving and I don't touch it until I'm ready to full stop [or restart stalled engine]. I could see some sort of potential concern related to wear and tear when I drop the clutch and switch to two-footing brake and gas, or when coming to full stop off of gas and full push in both clutch and brake at same time...but I'm just speculating. Maybe other situations as well?

I appreciate any technical related info related to this subject, specifically related to off-road driving. Also, I'd love to learn about the history of this type of configuration if anyone is aware. Is it just a more economical choice based on the assumption that drivers wouldn't use the TRD Sport model aggressively? Etc.

For those unfamiliar with this topic, I'll attach a couple pics for reference...


Although I might have the arrow pointing at the wrong reservoir, I forget which of the two is the dedicated clutch fluid reservoir tbh (I have a TRD Sport so can't confirm).



I'm looking to learn, please educate me. Thanks!

 

Separating the two fluids means the clutch fluid will no longer get hot from the brake fluid working through it, although I doubt any of us are driving hard enough to make that happen. Same can be said for the brake fluid getting hot from excessive clutch use.

Aside from that downside, the positive is that it’s cheaper to manufacture one common reservoir and one less thing for an absent minded American to check when doing car maintenance. Perhaps for some applications, one single tank wasn’t feasible for the real estate in the engine bay, which is why some auto manufacturers use separate ones.

 

Another thing to point out is the offroad has the hydraulic brake booster and the sport does not. Theres alot more going on with a hydraulic booster like an a accumulator and abs ecu.

 

Good info, thanks for that. Pretty much what I expected...I guess I just wanted to confirm the performance and wear-and-tear on my TRD Sport won't be excessively poor compared to a TRD Offroad, given that I wheel in 4Lo somewhat often. Granted, I agree with you that I'm probably not pounding the hell out of the truck hard enough to push the single reservoir over it's limits [hopefully].

I had no idea about that, man I keep finding new differences of Sport vs Offroad models that not many are aware of, even after driving one for three years. Can you explain more about the brake booster and what it does? I'm interested in that because [as far as I know] all 3rd gen Tacomas with a manual transmission come with a clutch accumulator [which I already deleted, and am much happier without it]. So that means with a clutch accumulator the brake pressure is also going through that right (at least for TRD Sport models)? So doing the clutch accumulator delete mod on a TRD Sport also affects brake pressure, not just the clutch...right? I think that might be a good thing...because it would mean the brake pressure should be closer to 1-to-1 if it doesn't have to go through an accumulator first. Or am I way off on the engineering side of this speculation?

 

The 09+ offroads had the hydraulic accumulator/booster for the brakes only, TRD sports had the standard vacuum booster. All manual transmissions on the 2nd gen had the clutch accumulator, which is an entirely different system. There were no trucks that I'm aware of that the combination of the hydraulic brake booster and clutch accumulator in a shared reservoir.

 

The hydraulic booster setup is used for the Active Traction Control (A-Trac) System that the TRD Offroad's are equipped with but the brakes are totaly independent of the clutch despite some models sharing a common reservoir.

 

I believe the vehicles with shared reservoir also have a divider that will prevent a clutch fluid leak from completely draining the brake portion of the reservoir, but not the other way around.

 

These points make me wonder if the separate/independent clutch reservoir is also a requirement on the Offroad models to even allow the hydraulic booster for A-TRAC. In other words, I wonder if A-TRAC caused the need for an independent clutch reservoir to begin with. If Offroad Tacomas didn't have A-TRAC, and therefore a hydraulic brake booster was not a requirement, would Toyota spend the extra dough for an independent reservoir configuration or just do a shared one like in Sport models? Makes me think.

Either way, this is all good info and has been very educational, thanks!

 

I'm guessing it's because there's alot going on in that unit when A-Trac is engaged so they want it to have it's own reservoir, otherwise I'm sure it's a cost savings thing.

 

Yea on all the ones I've seen the clutch fluid port is mounted an inch or so from the bottom of the reservoir as to not deplete the brake fluid completely in the event of a leak.

 

It's a cost savings thing. If they can find a way to save 2 pennies on a nut or bolt they do it. The term is value engineering

 

You are correct it has a dam in it basically forming two separate reservoirs when the level drops down to the dam level.