TH400 temp

[pismorat]

I just read a bunch of threads on tranny temp., but none really give me an answer to my question. I have a 489 BBC, TH400, NP203, 1-tons with 4.10 gears, and 37" tall tires. I have an isolated trans cooler with a fan.. Cruising down a flat freeway at 65mph, the transmission will be 170-190 degrees, but hit a hill or any type of load required, it'll shoot to 210-240. It always cools back down after some lighter load, but it even does this in 4wd. The engine rpm is around 2500, and doesn't vary going up a hill, but I obviously need to give it more gas to maintain the speed. Will these temps hurt me in the long run, and would going to 4.88's help or hurt in this situation?

 

[skunked]

The stand alone cooler (alone) is your first problem. I went through this with a couple different trucks and routing the transmission fluid through the radiator cooler and then through an auxiliary cooler fixed the problem. Fluid cools more efficiently than air therefore the radiator cooler works better once your fluid hits engine temp. Secondly you need to make sure your fluid warms up and the radiator cooler achieves this.

 

[sweetk30]

fluid to fluid = better .

flow threw rad first then aux cooler .

short bursts of temp are normal . but long holds at these temps = problems .

were is your sender ? pan / cold return line or hot out line before cooler ?

 

[pismorat]

I originally had the fluid going through the radiator first, then the auxiliary cooler. I have had this problem a while, so I thought pulling it out of the radiator might help, but I've not noticed a difference in doing so. The sender is in the pan.

 

[pismorat]

Another bit of info: I am also running the fluid through a Baldwin filter housing with a Napa hydraulic fluid spin-on filter. I assume this shouldn't cause a flow constraint, but maybe I should try and bypass it when I re-run the lines into the radiator?

 

[sweetk30]

been running my atf threw a spin on atf stand alone for over 10 years on the same trans no problems .

 

[pismorat]

OK, so I'll probably leave the spin-on inline and re-route the lines to the radiator again. I don't expect to see much of a change, but I'll just keep an eye on it while driving at freeway speeds I guess.