Tranny mods, valve body & torque convertor

Cowboy_Customs · 06-01-2007, 09:51 AM

Anyone install a suncoast or aftermarket valvebody in the pre lockup A518? Im curious on your thoughts, My next truck may be auto, so im curious on experiences. Also curious about torque convertors. Looking at suncoast for that too, they advertise 89% efficiency, whats good for the mild built (350 hp) 1st gen?

***Paccool*** · 06-01-2007, 11:43 AM

Hi Cowboy - hope you are starting to feel a little better!

I have the 518 in my truck. The tranny guy I use is an old high school buddy, we played basketball together. He rebuilt the tranny about 4 years ago and it has been fine. I've boosted the power in the truck a lot since then and it is still holding up well. Still shifts a little soft but that is probably good to help protect the drive train. He installed a shift kit and did a few mods in the valve body. Drilled out a couple of ports for better pressure. He also added a cluth disc or two to the packs so they were tighter when engaged. The line pressure is turned way up. The weak point is the OD section so I take it easy when playing. Most the time I take I out of OD when racing, on the dyno, or towing and it has been fine. I'm not a tranny guy so I can just go off what he says and the one thing he keeps telling me is" if you break it, bring it back and I'll fix it" so I can't argue with him about it!

He has serviced it several times and says there has not been any metal showing up in the pan. I was at Piers a couple of years ago and they put on a Mag hitech pan and we saw a few flakes that everyone said were thrust waashers. Brought it back and my buddy said the same thing and took the pan off and said it was clean. He said - Drive it! So, I'm driving it and dynoing with it and all has been well.

This doesn't answer your question directly but I thought you might like to see what my luck has been. I also have a DTT 89% converter, didn't see a huge difference but it did seem to grab a little better with the higher efficiency converter.

Oh yea, when I was looking at converters, Bill at DTT said that if I tow to use the 89% rather than the 91 %converter. He said the 89 would allow a little better turbo spool up due to the slight slippage the 89 gives over the 91%. If you are just racing or playing and not towing, the 91 would be a better choice.

Cowboy_Customs · 06-01-2007, 12:48 PM

Ok, thanks. Thats makes up my mind on the torque convertor then. I dont tow enough to even justify a dually, but when I do tow, it requires a dually. Its primarily a daily driver/fun truck.
Thats a sweet deal on the tranny guy for sure! Its common to see things like that in the pan, everything wears. Ive dealt with my fair share of slushboxes over the years. Im pretty good with autos, but its been gasser hot rods. Camaro's, hot 350 chevy trucks n such. But diesel valve bodys n efficiency ratings r new to me.