700R4 transmission Question/opinions

[rockable]

My engine/700R4 Combo has nearly 100k miles on it.  The engine gave up the ghost and I am replacing it with a 350 crate motor.  The 700R4 has only one leak, the speedometer cable drive which I plan to replace. 

My question is this.  Is there anything other than changing the fluid and filter that I should do?  I only drive this truck about 3k miles per year.  How long do 700R4s last when not abused and serviced?

[mikek20]

Is this on a 2wd truck? Personally if your getting good shifts and it still performs at top, i wouldnt do anything more than a fluid and filter change with a new tranny pan gasket. Now if your thinking of adding power to this crate 350 you may want to consider a lockup kit for the tranny and maybe a new detent "kickdown" cable to be safe.

[rockable]

It is 2WD and it has been working fine.  I'm putting a base crate 350 in it.  That's all.  All I planed to do was change the fluid, filter and gasket.

[mikek20]

Then what you have planned will work perfectly fine.

[Edahall]

How long do 700R4s last when not abused and serviced?

Well, that depends on the use, the engine in front of it, the weight of the vehicle, axle ratio and a host of different factors.  Considering that you've got a pre-87 700R4, I would say that yours has lasted longer than most.  That said, I would just keep driving it and when it does fail, I would find an 87 and newer 700R4 to stick in there.  If you're going from a 305 to a 350, it'll definitely put a little more stress on the transmission.

[bd]

How long do 700R4s last when not abused and serviced?

Well, that depends on the use, the engine in front of it, the weight of the vehicle, axle ratio and a host of different factors.  Considering that you've got a pre-87 700R4, I would say that yours has lasted longer than most.  That said, I would just keep driving it and when it does fail, I would find an 87 and newer 700R4 to stick in there.  If you're going from a 305 to a 350, it'll definitely put a little more stress on the transmission.

To maximize transmission service life, consider adding a trans fluid cooler in front of the radiator to supplement the factory wet cooler.