86_Dan_Z28

iTrader: (1)

This was a Bowtie Overdrives 2400 stall converter. It was working fine in till this. It chewed up the pump and left me stranded.

86_Dan_Z28

iTrader: (1)

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86_Dan_Z28

iTrader: (1)

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86_Dan_Z28

iTrader: (1)

Destroyed the pump.

Fast355

iTrader: (2)

Either the converter ballooned OR the crankshaft somehow walked toward the transmission under load (thrust bearing clearance wrong)

Perhaps the better answer is the pump itself failed and chewed up the converter.

My stock 200K mile 700r4 in my 87 GMC Jimmy did that recently and it only had a 3.1 sitting in front of it.

Randy82WS7

holy damn, thats crap! :O


how does a converter ballooon?

what does that mean exaclty- what exactly happens when one balloons?>

thans

Apeiron

Pressure inside the converter causes the case to distort and expand, called "ballooning". This causes Bad Things to happen. Anti-ballooning plates are steel plates welded to the case to reinforce it.

Fast355

iTrader: (2)

The converter is under its highest stress when it is fully loaded up at full stall with the tires stopped. At this point it is very possible for the converter to be under so much pressure that the converter actually grows, hence ballooning or blowing up like a balloon due to the stress. It is actually more common than the aftermarket converter manufacturers would want you to believe. I am fairly sure that converter ballooning is actually what broke the crankshaft in one of my 350s. I had a cheapy re-stalled 2,400 rpm converter in my 700r4 and the crankshaft snapped near the rear most rod bearing journal, less than 1,500 miles after installing the converter.

86_Dan_Z28

iTrader: (1)

This was a 13 vane pump. I think I heard before that they are not very good.

Fast355

iTrader: (2)

FWIW, all the performance trans guys scream for the 13 vane pump, but I still have the stock 1983 7-vane pump in my transmission. The extra vanes in the 13 vane pump actually take up space that could be occupied by transmission fluid to increase the volume of the pump. The additional cuts in the pumps rotor also weaken it more than a 7 or 10 vane pump. The aftermarket guys usually claim the fluid flows more consistantly with the 13 vane, which it does to a very minor extent. All the 13 vane pump really does is cut-down on the buzzing the pressure regulator made on the earlier model 700r4s.

Pat Hall

iTrader: (31)

Yeah, I've also heard the 13 vane pump is overrated and unnecessary from quite a few tranny builders. Dana at Probuilt uses the 10 vane pump in pretty much all of his rebuilds, along with the hardened pump ring kit, and we all know how good his 700r4's are. I talked to him not long ago on the phone, and he was telling me that GM had pretty much resolved most of the design flaws in the 700r4's by 88 or 89. By then, they had upgraded to the 10 vane pump, added the auxiliary valve body, forward clutch accumulator, redesigned some of the valves, and got the shift points about right.

Fast355

iTrader: (2)

In all honesty my 1983 G20 Van got the hell beat out of it from day one and still somehow the stock 700r4 managed to live on. It did not die until 285,000 miles and that was after beating on it for about 10K miles behind a 315 HP 350 TBI. When it died, most of the drivetrain inside of the 83 700r4 completely fragged. The pinon gears had pieces missing! The ring gear had chunks of metal lodged in it. The drive shell shattered. Basically the only good rebuildable pieces were the valvebody, case and pump.

I rebuilt a 1993 Camaro 4L60-NON E to replace the original 700r4. 3-4 WOT shifts into OD are fun, as are 5,500 rpm WOT shifts in every gear.

Pat Hall

iTrader: (31)

[QUOTE=Fast355;3269127]In all honesty my 1983 G20 Van got the hell beat out of it from day one and still somehow the stock 700r4 managed to live on. It did not die until 285,000 miles and that was after beating on it for about 10K miles behind a 315 HP 350 TBI.

I guess our TBI motors must be kinder to 700r4's because I've got 233,000 miles on my orginal trans behind my L03, and it still works great. I'm going to be putting a ZZ4 cammed TPI L98 in front of it in a couple of months here though, so I'm thinking the trans might buy the farm not long after I swap the motor. I'm going to put a 2600 stall converter, .500 boost valve, corvette servo, and a transgo kit in the trans at the same time I swap the motor, and I'm hoping that'll buy the trans a little more time. We'll see.

Fast355

iTrader: (2)

Mine ran its first 210K behind a carbed 305 HO, then I swapped to TBI, keeping the stock 305 HO, ran it another 65K miles, built a 350, installed it, and the 700r4 lived for another 10K.