Rebuild th400 or 4l80e?

[txaggie]

Howdy all!

I have an 85 454/th400 suburban and my first travel trailer pull (6miles in) caused me to puke out new tranny fluid out the vent tubes. The fluid came out burnt and black so I’m guessing the clutches are shot. Should I rebuild this thing (much cheaper?) or swap to a 4l80e (new shaft, controller, etc?)?

The turbo 400 looked good on the inside but I wonder if being 40 years old made it take the cake when I towed with it?

 

[idahovette]

Got a trans cooler on it?

 

[txaggie]

Got a trans cooler on it?

Yes. External cooler

 

[Ricko1966]

Yes. External cooler

In series with the radiator transmission cooler?

 

[Vbb199]

This is all a matter of opinion... it should be obvious

OD or no OD, to break it down to its lowest common denominator

 

[txaggie]

I daily drive

In series with the radiator transmission cooler?

not run through the radiator. Exterior only.

 

[NickTransmissions]

I daily drive

not run through the radiator. Exterior only.

Run it through the radiator then to the ext cooler. You're giving up a lot of heat exchange by not including the internal cooler in the system.

Also, Id swap in a 4L80E if it's in your budget to do so.

 

[txaggie]

Run it through the radiator then to the ext cooler. You're giving up a lot of heat exchange by not including the internal cooler in the system.

Also, Id swap in a 4L80E if it's in your budget to do so.

My tech told me it would be cooler if it didn’t hit the warmer radiator. More cooling time does make since.