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1-2 accumulator spring question

15K views 14 replies 9 participants last post by  Blaine B. 
#1 ·
1994 Supercoupe 4R70W w/ 3.73 rear gears. So the other day as I'm pulling away the car accelerates but doesn't want to shift into 2nd. Revs to over 3k, I let off gas, and then it shifts. This happens four times in a row and then I park it and drop the pan. The car does have some kind of shift kit or j-mod from the previous previous owner, but I don't have any details on it.

It still has the original 1-2 accumulator, and a broken purple spring on the bottom and no spring on top. I have the updated accumulator, and I still need to buy a new cover and spring.

So my question is: what spring, or springs, and where should I put it/them?

I was thinking of just doing an upper blue spring and no bottom, like would be done on a j-mod. Or should I just put the purple back where I found it (bottom)? Or all of the above?

I just bought the car and it was shifting great, 1-2 shifts nice and crisp, until the other day. I don't want the 1-2 shifts to be too harsh, they were fine before. But I also don't want to break another spring soon either.

Any suggestions?
 
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#2 ·
If a Jmod was done, the updated accumulators should have been in there already along with updated spring(s).

The crisp 1-2 shifts you had may have been from the broken spring. I'd go with the light blue spring upper spring and no bottom.

Joe
 
#4 ·
Don't ask me colors but I used these when I did my JMod (mild):
1-2 Top Spring F75Z-7F284-AA
1-2 Bottom Spring F7AZ-7F284-BA
 
#6 ·
A broken bottom spring won't cause late shifts. If anything, it would cause early shifts because the accumulator will fill quicker without a spring to work against, but that would be a very slight difference that you probably wouldn't notice. Now if the accumulator itself was stuck in the bore, that could cause a late shift. I say replace the accumulator itself with the updated design, reinstall your top spring, and leave the bottom spring out, and test drive to see if the problem is fixed. If it is, then great. If not, then that means you likely have a failed roller clutch as Buck stated, and you'll have to go into the trans, but before doing all that, if a new accumulator can fix the problem, then it is worth trying.
 
#8 ·
agreed, Lt blue upper and Violet lower seem to work work the best. If you want a very firm shift, remove the lower spring.

From personal experience, a broken 1-2 lower spring will cause a no shift condition IF the broken springs turns sideways and wedges in the servo piston.

Been there, Done that.
 
#9 ·
#11 ·
I thought that the upper spring was always supposed to be left in, regardless if the lower spring is removed or not.

Having it totally backwards like that with no upper spring and only the bottom spring....I thought that would cause a problem.

What about no accumulator springs at all? What would be the result? I would imagine it would be horrific.
 
#12 ·
I thought that the upper spring was always supposed to be left in, regardless if the lower spring is removed or not.

Having it totally backwards like that with no upper spring and only the bottom spring....I thought that would cause a problem.
Not sure who that is directed toward, but like I mentioned in the last post just above yours, I did use a blue upper spring spring and no lower spring. It does shift hard on the 1-2, but not obnoxiously so.
 
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