tranny question

[86grandnat.]

This one is about my hurst olds. I've been having a problem with my tranny lately, whenever i go to pass someone on the highway, it downshifts to 3rd fine, and as soon as it hits 4th its starts to bounce back n forth between 3rd n 4th gear. This only happens a WOT, it will stop if you let off a little. Now, the tranny is just rebuilt 2000 miles ago (200-4r) and its supposed to handle close to 500 horse. It also has a shift kit and a brand new 2400 rpm stall converter. I adjusted the tv cable probably a million times and that doesn't seem to help at all. Any other ideas of what might be causing this problem, thanks!

 

[WE4]

I moved this so...

You may get more hits. If the wife wasn't yelling at me to go I would type an answer now. If it is still unanswered later I will reply.
Blame it on her, wives..... you gotta love em'!!!!
( Because lawyers are just too damned expensive!!!!!!)
LOL


Bruce
WE4
www.PTSXTREME.com

 

[chris718]

a wot 4/3 kickdown confirms that the plunger is opening the detent passage an allowing the 90 psi of regulated modulated tv oil into the circuit leading to the mtv down valve and generating a response by the 4/3 shift valve to backshift it and exhaust the 4th clutch thru an orifice in the valve body placing the transmission in third gear.now,if you stay on the gas certain calibrations will not allow the transmission out of third until you reach close to 100 mphour.it sounds as if the part throttle passage in the plunger is the culprit.most of the oz and kz hurst olds calibrations do not have a part throttle detent passage in them allowing the car to stay in fourth gear at high throttle.also at high road speeds governer pressure is high enough to hold the valves from backshifting regardless of throttle plunger position to eliminate engine oversppeeding as well as being a by product of the calibration.a sticky 3/4 shift valve line up will give a similar problem at light throttle more so than wot.my 200 page manual covers this thoroughly as well as provides complete hydraulic schematics to allow you to isolate problems when your trans guy doesnt want to help because of lack of info on the trans

 

[86grandnat.]

First off, thanks for moving my post Bruce! Ok, thanks for the reply chris718, but most of that flew right over my head, lol. For the 1st month the car ran great on the highway, never had that problem, but then I got my carb. adjusted by a local mechanic and since then its seems to be acting up. He claimed that the vacuum lines wern't adjusted properly so he switched a bunch of them around. Since then, I tackeled a problem with the car shutting down for no apparent reason, which turned out to be the float spring was missing, hasn't done that since. The carb. that is on the car right now isnt the original one, its still a rochester but it doesn't have the electronic hookups like the factory one. If you need anymore information just ask, I will greatly give it too you! With summer here, I got to get one of these cars running, and the National is in need of a new turbo so that one is gonna have to wait a while. Thanks!

 

[77 cruiser]

One thing you could check for is press. loss at high RPM. Put a guage on it & drive it & see if the press. drops above 4- 4500.