After reading several posts on this forum I went out and bought a 4 oz. bottle of the Ford Friction Modifier for transmissions. My 94 F-150 with the 4R70W trans. was shuddering when it shifted into O/D. I removed enough fluid to accomadate a bottle of Lucas Trans. additive and drove for about 3 days. It helped to a degree but did not completly eliminate the shudder. So today I added the Ford product. Within the first few miles the shifting got smoother and the shudder disapeared. Just thought I would share this info. Emmett

 

Did you mean to say you bought a 4 oz. bottle of Ford Friction Modifier for Rear Ends to put in your Transmission?

 

That's what it is....... and it works.

"Ford Limited Slip Friction Modifier C8AZ-19B546-A"

https://www.ford-trucks.com/forums/s...d.php?t=459872

Sometimes there's something that works so well it's hard to believe.

 

That promotes a certain amount of slipping, that is why its for the limited slip rear ends. I would think that this is stopping the shudder by allowing the clutch packs to slip more than they were and will in the long run shorten the life of your tranny.

 

It's my understanding that Friction Modifier is used to prevent the gear oil from foaming up. The air pockets in the oil can cause damage or poor performance. If this is true then it must do the same in the auto trans?

 

Ok I would like some data from someone (ncranchero maybe) that has used "Ford Limited Slip Friction Modifier C8AZ-19B546-A" in their transmission.

What I want to know is:

1. How many miles to they get out of the transmission after using this.

2. If they use it a truck does the transmission slip under a heavy pull or load?

In other words is it true what wickymustang said?

 

It is what it says it is. Ford Motor Co instructed us to use it in our Crown Vic Police fleet (appro. 1800 cars) as a fix for transmission shudder. There has been no decline in longevity of our transmissions. I put it in my personal ex-police duty '98 Crown Vic when it experienced shudder. My car has 102,000 police duty miles and 59,000 personal driven miles ..... on the original transmission. We buy 150 to 500 new Crown Vics a year and I really don't think Ford would suggest using something that wasn't proven and jeopardize the sale of that many cars every year. If I could find the instructions in print I would copy them to you but I don't have them. Our dept. also uses it in all of the Fords including the pick-ups and crew trucks with the same success and no slipping problems, since you asked. I use it in my wifes Mustang and it will go in any other Ford automatic I purchase. When it is suggested by Ford for a fleet the size of ours, I'll surely put MY money on it. It cured my trans shudder almost instantly. If you wish to use it, great. If you wish not to, great also and I wish you luck in whatever other solution you find. I'm not saying this is the only or best solution. I simply shared our solution here in hopes of saving some folks a chunk of $$$. I'm not being a smart-a$$ but I have given all of the info I have. Unfortunately we haven't done controlled lab tests and I don't have chemical analysis of the product..... it just works and has had no negative effects on our vehicles. We have been using this for so long now that it's just routine. I for the most part want to know the who/what/where/why's just as you do so I understand your questions. Mr. ercaraker tried it and liked it so I've been a help to someone at least and I appreciate his sharing his success.
Now if you want me to share my motor oil using help/cure by using Castrol motor oil I can do that too ...... OK, I'll spare ya!

 

subford, yes I misspoke, the product is Ford Friction Modifier for Limited Slip Differentials which is what my garage owner said Ford recomends. As ncranchero said it seemed to do the job. I only wish I had tried it earlier. With 106,000 miles on my '94 I figured if it didn't work next stop would be transmission shop. I think over the last year I've just about reworked the truck. New brakes, calipers and rotors, rebuilt starter, balance and rebuild driveshaft, u-joints, carrier bearing,cruise and throttle cable, clockspring mech. Complete tuneup and new tires. Next up new shocks. I wouldn't part with it for just about anything. It runs and drives great. Later, Emmett