TRANSMISSION OVERHEATING!!

[Slinky]

Ok so i had my 4t60e rebuilt and it was rebuilt incorrectly causing everything to burn up even with a external cooler. So i took it to a reputable shop and had them rebuild it with hardened parts, trango shift correction kit, Torque convertor lockup and shimmed accumulators ect. I was assured by someone who rebuilt over 400 4t60e's that it was perfect,

It shifts and drives perfect now but still over heats. i know this because i installed a temp sensor in one of the lines. It seems like as soon as it starts going up in temp it just wont stop.

I should mention that i rewired the trans to the obd2 harness i installed in my obd1.5 engine if that would change anything.

I have the external cooler mounted to the front of the radiator by the way.
He also pressure tested the lines to check for leaks ect.

Anyone know why its overheating when it was rebuilt perfect?

Temps are rangeing from 180f-240f normal operating

[Barry]

Even at idle it will get hot or only when your ripping on it?

[Slinky]

i didnt go above 60mph, i didnt even go above 2500rpm, i drove really slow and easy and the temp steadily climbed up and up withing 10 mins it was upto 220f

[DTMAce]

Begs the question, what is the normal operating temp?

[Slinky]

i looked and looked and could not find it, the trans guy from the shop told me 140f which i thought was completely wrong seeing my engine gets around 200f

[Barry]

140 my ass. Maybe 140c, but that seems a little steep.

Obviously slipping clutches will build heat real quick but if your just cruising then something else must be generating the heat.

[3X00-Modified]

Normal operating temp is the same temp as the engine at most times.. since the stock cooler is part of the radiator... so you would typically hang around 180-190 since it is on the cool side of the radiator.

If your overheating like that then you have your pump pressure set too high. Do you have the adjustable regulator on it? And have you done idle and in gear pressure tests to verify it? Also if your TCC is not locking that can produce a lot of extra heat.

Probably would have spent less if you sent it to me to rebuild it for you....

[Slinky]

true but i was assured the tcc lockup is working perfectly, i have an adjustable regulatar but i broke the set screw in it and put my old one back one, what with the pressure ect could be causing this?

and what pump pressure do you mean?

[3X00-Modified]

your adjustable vac modulator controls the pump pressure in the trans... so if you had that adjusted too far up then your telling it to be at a HIGH pressure all the time so you in turn overwork the pump and overheat the fluid.

Do you have the modulator properly connected with a vac line and your positive it's seeing VAC from the engine? Once again even with stock if its not seeing engine vac its at max pressure all the time.

[Slinky]

got a proper vac diagram for a 4t60e?
with all the emissions stuff ect

[3X00-Modified]

It should come off the vac modulator and go directly to the intake via rubber then a metal tube to a vac port on the right front corner of the plenum. There should also be a T somewhere in that line that goes off to the vac canister and there is a one way valve on that line to hold vac in the canister.

[Slinky]

i will take a look when i get home from work tomarrow, could there be anything else causing this like a clogged trans passage in rad ect?

[DTMAce]

Thought you had an external cooler?? Or so you said in the first post?

[Barry]

The vac line is nothing special, just a port to the intake like Jon said. Your vac canister and hvac controls also run off that iirc.

[daguse5853z]

Thought you had an external cooler?? Or so you said in the first post?

some people still utilize the factory trans cooler and just plumb the aftermarker cooler inline so you have essentially 2 coolers.