Chevy Tri Five Forum banner

yesterday i smoked my 700r4

6K views 17 replies 10 participants last post by  55 Tony  
#1 ·
just getting my 55 chevy sedan on the road this year after a 8 year restoration.running a 454 roller motor that i had builit last winter,its running 540 HP on the dyno at the flywheel, and close to that number in tourqe.had a guy thats local drag racer, thats running big blocks in his trucks build trans.all i know is that it has corvette servo and heavy duty clutches in it.running a 3500 stall built by coan,411 9inch. talked to a trans shop,that i trust who drives a classic car himself and he thinks i took out 3rd and 4th gear clutches.next week he's going to take trans apart.my question here is,am i asking too much of this trans? I didnt consider that i was beating trans too bad.just standing start hole shots,just was taking my last ride of the year, before i put it away for the year.what are your thoughts on my situation,any suggestion.thinking i'm going to a 5 speed trans if this happens again.
Image
 
#18 ·
Does it have any kind of shift kit in it that increases line pressure over the entire range? If you have all that power without some extra hydraulic pressure holding the clutches tighter than stock, it's like asking for it to slip. Were the shifts at say half throttle sharp/hard that you really felt it? With all that power it shouldn't shift like your fathers Oldsmobile.
 
#15 ·
When you have the correct linkage geometry, all you need is to pull the cable taut at WOT. This also assures that the cable is pulling through the whole travel with no slack. The correct procedure for adjustment is simply to pinch the adjuster tab as you pull the carb linkage through its full travel, when you get to WOT then let go of the tab.

Any other adjustment attempt is fudging for bad geometry or just plain wrong.

The correct geometry is published many places on the net.
 
#11 ·
I was told by my transmission shop that the most important adjustment is the 1st-2nd shift point, and if it is set properly all else will be OK. It doesn't matter if your throttle can get to wide open or not if it's not adjusted for the right pressure throughout the travel. He told me the 1st-2nd shift has to happen between 20-25 mph, and if it doesn't none of the rest will work very long.
I simply drove mine and watched my GPS for the shift point. Then kept adjusting until mine shifted at around 22 mph. After that I checked when I got home to see if my carb could reach full throttle with the engine off, and it did.
 
#12 ·
I was told by my transmission shop that the most important adjustment is the 1st-2nd shift point, and if it is set properly all else will be OK. It doesn't matter if your throttle can get to wide open or not if it's not adjusted for the right pressure throughout the travel. He told me the 1st-2nd shift has to happen between 20-25 mph, and if it doesn't none of the rest will work very long.
I simply drove mine and watched my GPS for the shift point. Then kept adjusting until mine shifted at around 22 mph. After that I checked when I got home to see if my carb could reach full throttle with the engine off, and it did.
That may be true with your particular car but there are too many variables to adjust by MPH. Tire size, tire diameter, govenor, and load will affect when it shifts. The next guy could burn up his transmission if the TV cable is set that way.
 
#10 ·
The 3-4 clutch pack is a common failure point in stock applications it needs more than a corvette servo to live with your HP range Sonics has really good performance parts & shift kits for both 700 & 4l60e trans while faulty tv adjustment can quickly wipe out a 700 other things can also with that much stall you need as large a plate style cooler as you can fit or one with its own fan plus unless the trans has been modified for hydraulic lock up you have to make it work electrically & Id want the brake switch in the circuit but some probably disagree with that
 
#6 ·
Hey guys I was to understand that the TV cable is adjusted so that the throttle valve in the transmission is depressed fully at wide open throttle as not to impede wide open throttle opening is this correct ? also are all 700r4's in need of the electrical kit that incorporates the brake switch for torque converter lock-up ? Seems like I'm gonna learn too ! appreciate the answers
 
#7 ·
Hey guys I was to understand that the TV cable is adjusted so that the throttle valve in the transmission is depressed fully at wide open throttle as not to impede wide open throttle opening is this correct ? also are all 700r4's in need of the electrical kit that incorporates the brake switch for torque converter lock-up ? Seems like I'm gonna learn too ! appreciate the answers
That's correct, IF you have the correct "ratio adapter" on the carb lever. The safest way to set the TV cable is with an pressure gauge on the port above the shift lever. The pressure should start to rise as soon as the throttle comes off idle. This ensures you have max pressure all the way up to WOT.

If your using WOT, you should have it in 3rd gear so "OD and lock-up" is not involved.

To answer, Trans-go and Superior makes a kit to hydraulically lock up the TC so no electrical hook up is needed, that involves changing valves in the valve body.
There's lots of discussion if a brake switch is needed, with the electrical hook up. There are conditions where the engine can stall if the brakes are locked up before it comes out of lock-up.
 
#5 ·
A stock 700r4 is rated 350 ft. lbs. torque, but a well built 700r4 can easily handle what your engine is putting out. TCI makes their Street Fighter to handle around 750 ft. lbs. torque, and 1000 hp, so they've figured it out.
But even the best build around wont hold up to whatever your engine puts out if the cable adjustment isn't correct. More 700r4's die due to poor adjustment, than to anything else.
 
#4 ·
the tv cable is where i think i might have gone wrong.when i set the tv cable i was going on trans shop (guy that going to work on it now)and he told me how to do it.with the higher stall i found out thats its hard to get that tv cable right.i thought i had it right,but now that i think about it i think that it was slipping all the while.trans goes in late next week and ill find out what happened.the guy im going to is pretty sharp with the 700r4 so ill so what he has to say i guess. tires are street goodrich 255r60/15 so your right about not having enough tire.guy that origanaly bulit trans said 650 horse corvette is running one of his trans and it holding together so far.how many people are dragging with 700r4s?
 
#2 ·
What a beautiful 55 ! love the color love the stance and them wheels ! CLEAN ! Id pull the stick and determine the fluid condition . If its clean fluid then Id lean towards a mechanical problem
I dont suppose that you would drive it around slipping and burning it up. if it burnt up then slippage was taking place unbeknownst to you. Transmission troubleshooting charts will tell you the area in which your trans failed.sounds like one component that is used in third and overdrive . I am doing a 55 and wondered how you liked the the overdrive ? I hope to get mine together one day but thats down the road !
Regards
Dave