besides the tranny guy who replaced my front seal being a moron, i have a question for us pros to answer amongst ourselves (this guy didnt know the tc unlocks when u break)
i cant believe it. well anyway my car felt fine for a week or two, but know after i changed my valve seals for the engine and went to drive i first noticed this problem. when the tc locksup on acceleration the whole car shutters and pulsates. if i break to unlock converter but stay on gas it will unlock and there will be no pulsating feeling or jerky feeling. what could cause this problem to suddenly arise, it unlocks and locks fine and only have this problem when it is locked.????

 

My dad was getting converter shutter in his mustang. I changed the fluid and filter and put a bottle of lucas transmission treatment in and it stopped. Tranny is acting much better now. You could try that. Worked for my dads AODE.

 

it will help the tranny is fairly new and i just had all seals done and the filter only has 5000 miles and fluid is new clean and at proper level. my problem only happens when tc is locked .
thanks for responding though,
anyone

 

How old is the TC?

 

know how old. but i do know it was fine and now it has this problem after guy worked on tranny and i did valve seals. the car ran great and for 2 weeks after the tranny guy worked on it it ran ok then i noticed it after i went to test drive after i did v seals. idles fine and drives fine except in lockup. and it also unlocks and locks fine????

 

This happened to me too. It was the torque converter. It was going bad and would vibrate when it locked up. I had it replaced and the problem went away. I am in the process of rebuilding my 700R4 now in my newer 87 T/A, and I will not install an old TC on any rebuilt tranny just for that reason, good TC or not, any rebuilt tranny I use will get a new TC no matter what.

Saves a lot of work.

 

well like i said it was fine for like 2 weeks, now it is ok when locked but on acceleration when locked it pulsates the whole car. could this be because of incorrect tps setting? its a little off but is it possible. (im remaining in denile of the fact that my tc is dieing just because im not paying for the son of a bitch to come out again...

 

It is definitely a torque converter problem, but you may be able to live with it.

The tranny is freshly rebuilt, but have you changed the fluid since?

I would recommend changing tranny fluid a few thousand after any tranny rebuild. I had problems (on my rebuilt tranny) due to the break-in fluid that went away after a change. Figure that the rebuild has lots of assembly lube mixed with the fluid (or *** knows what else, I was looking for tranny assembly lube and asked at a tranny shop. They told me "oh we just use motor oil". Needless to say I'm never going THERE again).

But I would try changing the fluid before worrying about the converter. Then make sure it is at proper level after moving the gear selector through all the gears (wait 10 seconds in each gear) while it's idling just in case there are air bubbles in a passage somewhere.

Possibly even add a half quart or so over the full mark. If it doesn't help, take it back out (a piece of clean vacuum hose down the dipstick tube will let you suck it out without dropping the pan). But I think sometimes the dipstick marking isn't 100% perfect.

After doing all this go for a drive and see if it still shudders as bad. If so, it's new TC time. But my 150K+ 700R4 would shudder badly on lockup until I changed the fluid, then it would be better for a few weeks until the slipping clutches burned the fluid at which point the shudder would come back. So fresh fluid will sometimes help an old torque converter work for a little longer.

 

for responding. but i may not of made my situation tottally clear. tranny had few thousand miles(ran perfect) on it front pump seal leaked...got new seals put in...3 weeks later and after i did the valve seals in my engine. i noticed it would not shudder when entering lockup but as i accelerated it would pulsate the whole car in a rythmic fashion untill i let off the gas or mashed the gas or braked then gave it gas(to unlock the tc) is there anything on the eninge that i could of hit that effects tc lockup activity or did something the mechanic did wrong when he replaced my front pump seal mess up coinsidently at the same time i finished working on the heads valve seals?

 

OK So ALL the guy did was the front seal? I.E. pull tranny, pull TC, remove seal, install seal, install TC, install tranny?

The shudder on light accel still sounds similar to the behavior mine did when it was failing. I would always have to let off completely or push the pedal down until the TC unlocked. I think basically the TC clutch is slipping/chattering, possibly due to insufficient engagement force and/or clutch surface wear.

It could be cooincidental... I mean it seems like a heck of a wierd cooincidence, but if ALL the guy did was the front seal there isn't much he could have messed up. He wouldn't even have to change the fluid, just top it off (since pulling the tranny would mean spilling a little).

I really don't see how anything you did to the engine could have affected the TC lockup. The computer is the one deciding when to lock and unlock the TC, based on engine vacuum and throttle position... Valve seals really wouldn't even affect engine vacuum... [Just occurred to me: Double check that you don't have a vacuum leak somewhere, I.E. when you pulled everything to get the valve covers off that you didn't accidentally break or leave disconnected a vacuum line.]

Did the car sit for a long time while you worked on the valve seals? Like the whole two or three weeks? Or was that a weekend job? Sometimes sitting for a while (although even a couple weeks isn't THAT long) can cause something that was thinking about failing to go ahead and decide to fail. Due to drying out or whatever.

You have checked the fluid level after the behavior started, right? Just in case the guy installed the seal wrong and it is leaking.

If none of this helps, I guess your TC just decided this was a convenient time to fail. Sometimes it works that way... it's Murphy.

If it makes you feel any better, I had one just like this. I put a new carb on my truck (I drove it into the shop with the old carb, it was OK, carb was just leaking fuel so I needed a new one). With the new carb, it wouldn't idle right no matter what. Kept dying from lack of fuel, even though when it was running it would be rich according to my O2 sensor. No matter how I tweaked the carb it wouldn't run right. Finally I just turned it real rich and tried to drive home. A couple blocks later it died completely, nothing I could do would make it start. It just wasn't getting enough fuel.

Guess what it was... Fuel pump relay dying/died. The new carb wouldn't run right because the float level was up, down, empty, etc as the pump cut in and out. What the heck are the odds of that? The MOMENT I put a new carb on, the relay kicks the bucket. Totally unrelated to the work I was doing, I hadn't touched the pump, relay, wires, or anything. But... Murphy.

 

I totaly agree with Eggplant Jeff. Murphy is just a PITA.

 

for answering, he actually pullked the pump out too to change those seals...and i may of hit my tps off but i dont think it would cause that to happen ...or could it..it drives fine otherwise..in drive i feel a little wierdness but nowhere near as noticable as when tc locks up in od. and i changed the seals in two days..the valves are now at 1/4 turn past zero lash. oh well after the tps check my tranny guy is getting the car back i think....if that was the case(i need a new tc) for a car with my mods(should be below) what tc should i get stock or bm, tci, etc. by the way im not rich
thankyou guys for your help

 

If you just want a stock replacement, I have one for sale on ebay, item # 2446652937. It has never been used. But if you want a slight stall speed check out the B&M Torque Master at Jegs. They are $215.00. I also have a bran new TCI 10 vane front pump that I didn't use. It would be a good upgrade if you have a stock 7 vane pump.

 

anything else cause this noticable pulsating on acceleration when in lockup besides the tc?