Manual trans fluid temp: Cats next to cooler lines

[TheBrightSide]

I just recently installed my factory two-piece, cast iron exhaust manifolds, with the downpipes (has 4 cats). The downpipes with all of the four cats, are pretty much directly next to all of the transmission cooler lines now. Before, I noticed that installing long tube headers drastically decreased the trans fluid temps, especially if I had to idle for a long time, or if I had a really long drive in heavy traffic. The trans fluid temp would be in between the quarter mark (105 F degrees) and the halfway mark (180 F), and maybe a bit over if that.

Now, with the stock exhaust manifolds/downpipes installed, idling for long periods at operating temps or driving in super heavy traffic for a while, can get my trans fluid right up to the halfway 180F mark or a bit higher even. Driving back to highway speeds of course, will then cool it down maybe anywhere from 10-15 degrees, but it looks like the stock downpipes create a lot of heat soak for the trans fluid.

I'm in the process of doing emissions in my state, and the cast iron headers were a PITA to re-install, so I'm really not looking forward to doing this every 2 years... I sold my BBK 1-3/4" shorty headers, with the catless downpipes, which are discontinued and I regret that.. I might get another pair of shorty headers again and then run some high flow catted downpipes, if I can take forever to find some for sale again.

[TheBrightSide]

I think I’m gonna carefully unbolt the mounting brackets of the factory trans cooler lines (some on the transmission bell housing, some around the engine block area), undo the quick connect/disconnect(?) lines from the transmission and the factory radiator, and then I guess I’ll just use either fiberglass or titanium-based heat resistant sleeves on them.

It’s pretty much what I did for most of my stainless steel lines, like my clutch line and my engine oil cooler lines. Just buy roughly a bit bigger than the diameter of the (hard) lines, and then sleeve them, and cut off roughly towards the ends. I’ll just use small, skinny zip ties and like use 3-4 in a row at the ends of the heat resistant sleeves.

The stock cats certainly heat up my transmission cooler lines a whole lot more than long tube headers and (secondary) high flow cats do. Plus, the factory cast iron exhaust manifolds/headers seem to retain more heat, but probably transmit that through the engine more as well, I’m assuming… Both my engine oil and transmission fluid have gone up anywhere from an extra 10-20 F degrees since re-installing the stock two-piece exhaust manifolds/headers.

[CamaroCracka]

The silicone coated fiberglass sleeves are far superior to plain fiberglass but of course cost more.

[TheBrightSide]

Originally Posted by CamaroCracka

The silicone coated fiberglass sleeves are far superior to plain fiberglass but of course cost more.

I was actually debating those. The Tick Performance stainless steel braided clutch line looks like it came with a similar wrap, from when you buy it. Hmm… as far as keeping temps down, I think I might go with what you mentioned.

The fiberglass is the cheapest option by far, and titanium is around like the middle price point. Although, I’m trying to think… If the transmission fluid were to get that hot (which gets the coolant hot), wouldn’t that reduce the effectiveness of my radiator at that point?

I can only imagine how the power steering and transmission fluid would do at the track… Probably also another reason I want a 13+ SS, so that I can opt for the electric power steering. Considering how hot my engine/engine oil still gets with my 25-row oil cooler, after I deleted the factory engine oil cooler; I’m not super keen on having my trans fluid run that hot, even if it’s considered “normal”.

I can’t see any single upside to having my trans fluid run around 180-200 F+ degrees, unless it can handle it any better than engine oil. I notice that around the 200-215+ F mark, driving hard and going through the gears, it starts feeling notchy and starts wanting to grind (and may crunch a bit). I would theoretically run my usual 75w-80 GL-4 gear oil, or Tremec’s HP MTF (75w-85 gl-4), but those also take ages to warm up.