advancedautomotion

More clutches and steel plates means that the drum has to be machined or the plates are significantly thinner than the factory plates, which means that they will heat up an warp quicker than thicker plates.

Most of the "Performance" Auto trans rebuilders simply up the line pressure which works well until the drum split due to the added forces.

If you going for a stock style rebuild ask TozoM8 he's done a bunch of them.

Alpha6-27Tango(jeff)

Ya, I can't quite wrap my brain around how you fit more clutches and steel plates in there. I've seen some pics of a 5HP19 disassembled, and there's not much room.

If 517 is adding more steel plates and clutches, do you have any idea where they're sourcing them? I'd be really surprised is shops like 517 are custom fabricating thicker clutches and steel plates.

I'd love to just send my transmission to them and be done with it, but it's WAY too big of a gamble having your transmission shop 2500 miles away, and $1500+ in shipping and shop labor if there's ever an issue.

Alpha6-27Tango(jeff)

Not sure if anyone cares, but thought I'd post what a local transmission shop (one of the 'go-to' shops in town for ZF transmissions) said when asked about adding additional clutch plates to the 5HP19:

"Yes, you can add additional friction-plates (clutches) if you know what you're doing. It requires machining the drum and snap-ring grooves, but it's definitely do-able"

He said it's VERY application-based, meaning a TH guy isn't going to know how to do it on a ZF, but if you trust the ZF guy, then yes it will work but typically you'll only one or two more plates in.

When asked "is it worth it"? He said:

"Typically no, only because the increasing the line pressure in the TC and VB is what really keeps the clutches from 'slipping'. Adding the additional clutch plates will help with slippage during power-transfer (between shifts), but there's other ways to mitigate that, like letting off the throttle".

Which all makes sense to me... If you want to be able to shift at WOT (Wide Open Throttle) with 500hp, then add some clutches. Else, increase your line pressure with a TC/VB upgrade, go easy during shifting, and you should be fine.

So for anyone considering the 517 full-rebuild with additional clutch plates, I guess you can consider this validation that what they're doing makes sense for increasing longevity for high-HP shifting.

slowguy

When I bring up "upgraded tranny" issues on these forum (as you may well know) the first thing you hear is do a six speed swap. Although the best option for power, I've explained my position on this. What I didn't know (and thought I would repeat now) is that the manual will deliver something like 20% more hp to the wheels. I found this just amazing.

I plan to keep the tip until the first time it breaks. Then I will probably do the swap, build a 600 hp beast, and buy another daily driver.

2.7Lturbo

Im sorry this isnt brought up more, but yes, you get a considerable amount of power transfer back with a manual. no fluid loss in the TC on a manual = better power transfer