New never used GN1 heads

[YoungGN]

Hey guys, I'm pretty new to this forum (and forums in general) so please forgive me if in doing this wrong.
Background first, basically, my 1987 grand national doesn't shift under WOT from 1st to 2nd. It will at about half throttle, but in WOT it just refuses to shift and revs out. Every other shift is great, grabs first gear out of park great, reverse is great. So I've been trying to trouble shoot this (among other things, cracked headers etc.) As far as I can tell, this car was mostly stock, I've just been spending the past few months trying to fix it's kinks. I haven't checked line pressure, and it's not running at the moment as I'm working on other parts of the car so I can't check it for awhile

I had figured the 1-2 spring was broke, so I opened it up to check it and it's fine, but I noticed this kinda pin plugging the accumulator housing and I was wondering if that's supposed to be there, or if that could be the issue? Thank you!

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[SS/GN]

Need more info. What is used for spring and piston. I dont plug them as I believe it needs cushion to make stuff last. JMHO

 

[TexasT]

I would be looking at the governor and making sure it didn't "throw" the spring. Have you pulled the gov down yet?

 

[YoungGN]

Need more info. What is used for spring and piston. I dont plug them as I believe it needs cushion to make stuff last. JMHO

I think it's the stock piston and spring in the accumulator, I haven't changed it at all, just trying to figure out if the previous owner has and if that's the source of my problems. Is that pin-looking-deal on the side suppossed to be there? Or should that be a hole?

I would be looking at the governor and making sure it didn't "throw" the spring. Have you pulled the gov down yet?

Yeah I pulled the governor down to check that too, the spring was still in it

 

[INEEDAGN]

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[TexasT]

I think it's the stock piston and spring in the accumulator, I haven't changed it at all, just trying to figure out if the previous owner has and if that's the source of my problems. Is that pin-looking-deal on the side suppossed to be there? Or should that be a hole?


Yeah I pulled the governor down to check that too, the spring was still in it

Does the governor appear to have grind marks or holes drilled in it? The accumulator doesn't initiate the shift it cushions the shift and how hard the clutch applies. The shift is intitiated by the VB shift valve and the governor.

 

[TexasT]

How hard is a bad way to describe the clutch application. It is more of how quickly the clutch is applied. And clutch setup, line pressure and the spring, and hieght of the piston all affect that.

 

[YoungGN]

Does the governor appear to have grind marks or holes drilled in it? The accumulator doesn't initiate the shift it cushions the shift and how hard the clutch applies. The shift is intitiated by the VB shift valve and the governor.

I don't believe the governor looked like it had any grind marks or holes put into it, next time I'm up at my shop I'll re-pull it and double check. If it's not the governor, what would you suggest I look at next? Could that shift valve be plugged by debris? Just a heads up, this car has somewhere around 120k miles on it, and judging by how the trans fluid looked, it hadn't been changed in quite awhile. Thank you again for the advice and help btw, I'm pretty new to auto trannies so it's definitely appreciated

 

[TexasT]

Well, if it were mine, and I changed the fluid and filter after it not having been changed in a long time, I would be preparing for an overhaul. Might not happen for you but I rarely change trans fluid on a high mile vehicle as I've not had good luck doing it.

That said, I would keep an eye on the fluid as the new stuff has "detergent" in it and it tends to "clean" up the insides and that equates to a lot of "floaties" in there that clog things up. Not saying this is what you have but it could be.

I'm guessing you have had it up and running and driving? When you drop the pan again, how much "crud" and debris is in the pan? does the filter look like it is flowing the fluid? I guess, I would have a gauge on the trans to measure the pressure and see just where you are with that. If the pressure isn't coming up it won't shift either. I have a line with 1/8" fitting and 3" 300psi gauge to tape to the windshield to watch the pressure.

Might have to drop that vb for cleaning but I would keep the fluid full and an eye on it and drive it. Might disconnect the tv at the throttle body and with the engine running give it some sharp tugs. Nothing to rip it out of the trans, but cycle it to maybe clear out any debris that might be in the tv valve.

Just spit ballin' but that is what I would try before i did more drastic things.

 

[SS/GN]

Good advice^^ right here.