69-chvl

iTrader: (11)

Even with only 11psi I can't get into 3rd gear. Normal driving it ok, and the trans shifts fine otherwise. I installed the Transgo bleeder valve deal and installed an additional check valve to bleed any residual pressure - no changes. What else can I do? The mechanical modulator/700 cable deal will approach $200.00 and I don't think I want to spend that kinda money for something like that unless necessary.

Thanks!

NorthTexasConverter

I would stay away from the mechanical modulator, you could easily get into boost and make big torque at low throttle angles.

If you get into 3rd gear, then into boost, does it stay in 3rd gear?

69-chvl

iTrader: (11)

Actually, I did do a 3rd gear boost run, but when the boost started to come in strong, the trans forced itself into 2nd and it didnt feel very nice the way it did it - like it was being forced to do it. I dont havethe kick-down hooked-up either.

NorthTexasConverter

Ok, I would put a pressure gauge on the transmission.

Jake's Performance

iTrader: (2)

Call the shop and I'll give you some insight.

69-chvl

iTrader: (11)

Thanks Jake but I don't want to bother you at work. I just want to make sure I did all the testing I can do before dropping the trans. I tried running straight manifold pressure, same thing - no shift to 3rd. Trans Specialties is basically down the street, I was going to have them look at it.

RonSSNova

iTrader: (3)

Vince and I have been discussing via PM for awhile.

I use a vacuum check valve that was OEM on turbo Biuck GN cars. Goes inline with the vac modulator so it can/t see boost. I tested it with a bike pump to 30psi.
On the modulator side of the valve, I drilled a .020" hole so the vacuum has a vent otherwise it would just hold vacuum in the modulator line.

It works well.

I had issues with the 1-2 shift after turning up the boost but it turned out that the boost comes on so hard, the rpm climbs faster than I could move the shift lever. There is a slight delay in my 1-2 shift, and in that slight delay, I was on the limiter.

Ended up just letting the trans do the 1-2 shift, and it does so at 6200. I've no idea why that rpm. The big block would shift at 5000, but it had nowhere near the power or rate of change in rpm. So that might be it?

I gave you a call today Jake. No doubt you are busy. I would like to discuss taming down the harshness of the 1-2 shift. It is pretty brutal. I have the 3 plate intermediate kit that you set up for me.

Ron

69-chvl

iTrader: (11)

Burned-out high gear clutches.............arrrrgggggghhhhhhhhhhhhhhhhh

Jake's Performance

iTrader: (2)

There are some tricks to running boost with an auto shift TH400 that I have developed through the years. If it's burning up high gear clutches there's a couple of things to pay attention too. Nothing I want to discuss online but you can call the shop.

69-chvl

iTrader: (11)

You know what Jake, this thing never had 3rd gear since I installed it.

Trans was given to me by a neighbor who had a "performance rebuild" done to it. I dropped it off at Trans Specialties in PA and they called me later that day stating the high gear clutches were gone, and that there was no shift-kit installed at all, and it was just a stock rebuild and it look like somebody installed somekind of "ball" or whatever to increase performance or pressure of the trans. Builder feels there wasn't enough line pressure for the kind of power the car is making. They talked me into the sprag/drum upgrade, clutches and a shift-kit. They really wanted a manual valve body in there but I resisted.

They only want 430.00 for a 10" converter for my turbo car - sounds too cheap???

Jake's Performance

iTrader: (2)

Trans Specialties is good. They make some of the parts we use for converter builds and they've been around for a long time. Sounds pretty cheap but depending on power level it may be fine. That's likely a furnace brazed, non billet setup.
Yeah if the trans wan't built properly, it won't last, especially if it was stock.
A shift kit may help but I learned some lessons along the way making auto shift valve bodies work with big power and boosted combos.

69-chvl

iTrader: (11)

Thanks Jake.

It is a furnace job but I was honest about the use of the car and they feel the cheaper converter is more than adequate for street use and don't want to oversell me.