BRF trans question

[gusszgs]

Just curious, did the '87 BRF Trans get any "better" hard parts than the others from the factory? ie: drum, sun shell ect.... I know the converter is different, the servo, VB and governor but any thing else?

 

[Shawn N]

Just the bomb that is set to to explode once you hit 400hp

 

[INEEDAGN]

all calibrations of 200-4r started getting a hardened sun gear shell starting around late 84.

There are subtle differences between performance units and other calibrations, mostly thrust washer differences, and that the forward and direct clutch housings have all the return springs installed. But they had the same hard part strength.

 

[INEEDAGN]

Brf planetary with "batwing" thrust washers...

Regular planetary without "batwing" washers...

 

[INEEDAGN]

Photo showing the 2 types of production plastic thrust washers and the brf metal thrust washer (between the sun gear shell and low/rev clutch housing). Pretty sure a 4 tab metal washer from a 400 works also...

...but doesn't matter because all the cool kids are machining the housing for a Torrington bearing

 

[INEEDAGN]

Brf direct and forward clutch return springs

And some crappy pics showing regular production drums without all the springs installed.

 

[INEEDAGN]

The BQ got the same stuff...others like the cz might have...I've never torn down an unmodded cz.

 

[TexasT]

I thought it odd that the factory decided on 16 springs for the brf in the direct and the gnttype.org article instructs on taking four out. Anyone able to explain which is better or why the factory went to 16 on the hp models?
http://www.gnttype.org/techarea/transmission/200rebld.html
I think it might have to do with the direct applying itself at high rpm, but I'm no guru.

 

[INEEDAGN]

The gnttype info is old info. the current crop of builders have studied these things and tried just about everything that can be tried. The extra springs help against centrifugal apply and help release the directs faster on a 3-2 kickdown. In fact, I've read info suggesting all the top builders are running stiffer than stock springs when dual feeding.

 

[INEEDAGN]

I doubt it matters much what you do with the forward clutch springs

 

[mikestertwo]

I thought it odd that the factory decided on 16 springs for the brf in the direct and the gnttype.org article instructs on taking four out. Anyone able to explain which is better or why the factory went to 16 on the hp models?
http://www.gnttype.org/techarea/transmission/200rebld.html
I think it might have to do with the direct applying itself at high rpm, but I'm no guru.

They use 16 springs on the HP because of the larger intermediate servo. 3rd gear oil is used to push the band off on the 2-3 shift. With the larger servo it takes a little more pressure to push the band off. The extra springs help alleviate any binding (engaging 3rd before the 2nd gear band is fully released). When dual feeding I use heavier springs. Dual feeding requires approximately half the pressure to engage the direct clutch so the binding is more pronounced. Using heavier springs gets rid of the binding.

 

[gusszgs]

Good info, thank you for the pics. I'm slowly doing a BRF and wasn't sure if the FWD Drum was a better piece or not from the non-brf. I'm not going to dual feed, so not sure if I need to go to a billet drum. I'm thinking not. Will only be 450hp max if that

 

[TexasT]

If you do go to a billet shaft forward drum I would seriously consider dual feeding. Lot of money for that drum and not take full advantage of its capabilities.
That said I didn't put one in due to budgetary constraints. Maybe on the next one if we break it I can convince the CFO of the "need".
Great info on the springs, and fact that larger servo needs more pressure(and I would guess additional volume wouldn't hurt) to get a clean 2-3 shift.