Ford 4r100 auto trans shift kit question

[SeanKroll]

I suspect/ guessing a troublesome shift kit in my trans from old oil making it sticky.

Reverse engages at startup when cold. First gear doesn't want to engage for a short period, then will engage and act normal with full power, as much as I can tell.


I'm guessing the oil warms and thins a bit, somewhere between 20-30 seconds on warmer days.


Fwiw, I either let the transmission warm more before driving to the county road (45mph ++) from my house, or drive it at about 15-20 mph out of my gf's neighborhood for half a mile, then into 35mph roads.


I'm guessing the oil

 

[Cobleskill]

When you change it add a bottle of Lucas. My mechanic bud isn't big on additives, but he really likes that one.

 

[CurSedVoyce]

Your transmission might be ok with new oil. It relies on the friction modifier in it. N eeds Mercon 5. Stay away from " equivelents/compatables" if possible. Dont cheap out.
Dropping the pan, changing the filter, draining what fluid you can that way will tell you a lot. Magnet in pan might have caught some things you might want to see. Same for the filter. Cheap inspection. Might make it go better. Dark fluid is old and got hot from friction. Should change it out about every 50K in my book. Same with your diffs.
I do not recommend a flush as that can cause other issues stirring all the particles up. You can drain the torque converter if it has the drain hole plug, through the inspection plate. You can drain the lines and cooler too if you want to go that far. Not really necessary. Especially if you are going to limp to a replacement/rebuild.. gasket kit and filter are cheap. Best use OEM. Power Torque makes a rubber one for the pan some folks prefer. My cork oem gasket only started leaking after 40k on the rebuild unit and the track sat. Easy enough to tighten the bolt just a touch. Torque spec is pretty light. Just done over tighten, you'll warp the pan and will have to straighten it to get it to seal.

 

[SeanKroll]

Thanks. I've already changed the oil and filter. It was not obviously dirty or glittery.

It's a government surplus truck that I've had for 30-40k. Don't know how long before sending it to surplus that the oil was changed.

135k now.


I was curious if some additive, now (after draining the right amount) might help.