Jbrew

That might be the better choice given it's just in OD. Will the truck still brake torque ? Yea mine wouldn't, it would slip in every gear. The fluid was dirty and non synthetic, - that could of been the major problem I expect, there was quite a bit lining and clutch material packed in the valve body. Have you seen my recent post helping another with this ? It's around , here's the pics I uploaded to help that user, -

https://www.f150forum.com/g/album/4293099

Well, if the modifier doesn't noticeable help....yea it may not be worth investing more cash or dedicating more of your time into it. I took a chance, it paid off.

jprevat

iTrader: (1)

I just tried the modifier. It helped but when any hill comes into play or i gas it, but not enough to downshift, it slips. Looks like the search is on.

I have not seen it. I will read through it and see if i have a light bulb moment. Thank you again Jbrew.

Jbrew

No problem, good luck jprevat.

jprevat

iTrader: (1)

Thank you sir. I found a local company here that builds a better 4r70w. Heavier parts, shift kit, with same day turn around, and a 2 year unlimited mile warranty for 1500 installed.

I dont think I can say no to that.

Holicori

If you are only slipping in OD, and if your fluid is indeed clean, I would blame the servo pin. If your band was burned, your fluid would look burnt.

You don't even have to pull the trans to do this. Sonnax sells a modified servo pin to swap in. The reason is because the bore the pin sits in wears out over time and loses the seal/pressure it had. The new sonnax one can be had individually for about $15. It is bigger and has an oring on it.

All you have to do is pull the cover, valve body (keep it hole) and you can get the servo pin. Actually, think you can get to the servo by just dropping the cover!

I'd at least give that a go.

Holicori

$20 (and new fluid) and an hour of work.... Versus $1500 for rebuild.

jprevat

iTrader: (1)

I will definitely check this out. It was definitely not a gradual thing. It was running just fine then it just slipped and never caught back up.

You couldnt happen to be able to point me in the direction to know where to find this pin in the trans could you?

2002FX4

http://www.sonnax.com/parts/2379

jprevat

iTrader: (1)

Yep that is what I ordered yesterday. It looked like it could be a little daunting at first but the process shouldnt be all that bad. I dont think. Lol

Jbrew

Yea, update the thread when start, with a few pics if you can. I'm curious for sure. I believe I have the kit, but don't think I installed it. Under the impression that I had to remove the trans at the time. Perhaps I'm not recalling everything as well, - it was 140,000 miles ago lol. Cleaning the valve body/accumulator, shift kit and great fluid did the trick for mine at the time.

So perhaps I'll try this, can't hurt.

Hey , it'll get me out of body work for awhile anyway.

Thanks for the post Holicori!