[bonnebird]

im rebuilding the forward clutch pack on a th400 and im fitting 5 frictions in place of 4. I have a spare new .060" steel to use with the extra new friction and removing some material from the piston. What I need to know is if there is a problem with using the .060" steel rather than a .078 steel. the other steels im using are .078"
Thanks

[Schurkey]

Given that the forward drum is not a "shifting" clutch pack--it engages and disengages at low throttle and zero- or near-zero vehicle speed--I don't think that would be a problem.

OTOH, I don't think adding a clutch to the forward drum is that big a deal, for the reasons previously given. If you're burning up the forward clutch, I'd be concerned that there's something else wrong aside from "too few friction discs".

Folks tend to be more concerned about adding a friction/steel to the Direct drum.

[Dragncar]

T400s, a little loose is good.

[chuckies76ta]

Well, it's either that or cut the piston a bit more and use the .078 steel. Sometimes you don't have a choice as you need to mix and match to get your proper clearance. It will be fine.

[Half-Inch Stud]

Thin steels in the FWD pack are fine. Just opened a 1973 TH375 FWD pack; it had 4-frictions that had 3 thin steels.

Good shape, and going to rebuild as a 5-friction pack.

[Cliff R]

The forward drum isn't fussy. You just have to pay close attention to a few things. First you need to decide if you are going to used a waved steel or not. Leaving out the waved apply steel can cause a pretty abrupt engagement if you have a really tight converter and/or your engine idle speed is pretty high due to a big cam installed or not being able to get it to settle down and idle well at a reasonable RPM.

You will see many different arrangements on the TH400 far as how the factory stacked the drums, the forward drum came in many flavors. I prefer 5 standard thickness steels and frictions and see no reason or advantage to try to add more frictions by using thinner components. The problem with thinner parts is that they lack the integrity to take the heat as well as thicker ones. Still probably not an issue with the fwd drum as it's not involved with a shift.

As a side note anytime you machine down an apply piston decide what arrangement you are going to use first and do the math so you factor in end play in the clutch pack. Also make sure when adding frictions that they will not drop deep enough into the drum that they woln't drop out of or not be engaged with the splines that drop into them, being the forward hub in this case. There should be PLENTY of room to build a 5 clutch pack fwd drum with stock thickness steels and frictions so typically it's not a concern.......Cliff