ok NOT to add friction modifer when I change gears
 

I was told by a guy not to add friction modifier when I changed the gears in my GT. He said the clutchs will wear out a little faster but that the posi would work way better. He said I would need clutches ever 60-80K miles.

I'm gonna add extra clutchs

So is this true?

I just got my Auburn Pro from Moser on Friday and it says in the instructions that you MUST run the Ford Friction modifier in order to help reduce clutch chatter. Interesting what he said.

Anyone know if it's true? My mechanic recommended that I put it in.

E

Josh, I've heard the same thing you have about not using it. So when I replaced the clutches in mine, I didnt add any modifier at all (didn't want to smell that crap either)
I have no chatter whatsoever and its holding up fine with about 15-20k on it since then.

Another thing. Try to get to a junkyard and get the trac-lock S-spring out of a F150 rearend. They are stronger than what you've got now.

I use Mobil synthetic gear lube and I personally prefer not to use it. I have no chatter, traction loc works fine. I really don't care if it wears out any sooner, as it is not hard to rebuild anyway. I think it's comes down to what you want to do, because you'll get different from everyone.

A lot of the synthetic gear oil's contain the friction modifier, so, no need to use it with them.
You will get clutch chatter without it in conventional gear oils, and, it is plain embarassing the noise it makes.
With the extra clutches, I'd not worry about wether it'll grab harder or not. Mine was rebuilt 25k miles ago, has over 300 passes on slicks, and has been thru a gear change without being touched, and is still hooking on hard and locking up perfect.

Good Luck.

I always assumed friction modifier was necessary for the posi clutch action to work properly! I don't know what the trans shop put in, but I know they left out the friction modifier after saying they'd put it in.. The cover was leaking so I had to have the rear-end serviced over again..new gear lube was installed, friction modifier was added, and the cover was replaced. During the week or so I ran without the modifier, there was no chatter, BUT the POSI acted 'strangely'. When I hit the gas, the car seemed to lose control more violently...it tended to do a hard veer to the left whereas with the friction modifier, the car stayed more/less straight. Don't ask why, I don't know!

[QUOTE]Originally posted by Nixon1
I always assumed friction modifier was necessary for the posi clutch action to work properly! I don't know what the trans shop put in, but I know they left out the friction modifier after saying they'd put it in.. The cover was leaking so I had to have the rear-end serviced over again..new gear lube was installed, friction modifier was added, and the cover was replaced. During the week or so I ran without the modifier, there was no chatter, BUT the POSI acted 'strangely'. When I hit the gas, the car seemed to lose control more violently...it tended to do a hard veer to the left whereas with the friction modifier, the car stayed more/less straight. Don't ask why, I don't know! [/QUOTE

you were probably only spinning one tire before you put in the friction modifier

Well that's why I was questioning about the POSI working properly or BETTER without friction modifier.... :confused:

I have been in my differential 5-6 times, I have built 4-5 others. I have never used friction modifier. And have had no problems related to that.

When i first got my car, the rear wasnt locking up at all. I was just frying one tire. I changed the fluid and put in the friction modifier and it has worked great ever since. Theres no way to know if it was in there before i changed the oil in it or not but I know it works great now.