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Late 1-2 shift intermittently 4R70W
Posted: 2021 Jun 30, 00:22
by m-barans
So sometimes my 1-2 shift is so retarded/delayed that the rev limiter is hit and the car stops accelerating of course until the shift is made. My first thought was the main control/ valve body but now I’m thinking it’s maybe a broken 1/2 accumulator spring or something. What to check? Should I buy the violet and light blue springs for the 1/2 accumulator? The trans only has 60k on it currently. I’d like to have minimal down time. Can I yank a newer 4R75 valve body from a yard and potentially use that if needed? Im not looking for anything super aggressive shift kit wise but open to suggestions for my 03 marauder trans. Thanks
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 01, 21:15
by decipha
the 1-2 shift can be made as firm as you want in stock form no problem.
Go kick up the 1-2 tv pressure table
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 02, 10:25
by Blocmi
Did you change rear gears?
Many people run into this problem when going to a higher rear gear ratio. I suppose it could happen with more power as well...
It's all about clutch fill time vs how fast your rpm is climbing.
IIRC there are a couple options to remedy.
1. Command the shift at a lower rpm so the clutch has more time to fill...
2. Enlarge a hole in the valve body separator plate to allow the intermediate clutch to fill more quickly.
Keep in mind, the 1-2 factory aluminum accumulator is known to wear out quickly on early transmissions, if yours is a 2003, it may have the bonded rubber already. If you're pulling the pan, it can be checked and or replaced with a bonded rubber replacement without dropping anything else.
I found the TCCoa forums (Thunderbird car club) has a wealth of information on AODE/4R70w mechanical function, issues, troubleshooting, rebuilding, and modifying.
https://www.tccoa.com/forums/automatic- ... sions.990/
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 03, 20:35
by decipha
No need in doing any of that just simply kick up the 1-2 as stated in the previous post
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 05, 00:23
by m-barans
Blocmi wrote: ↑2021 Jul 02, 10:25
Did you change rear gears?
Many people run into this problem when going to a higher rear gear ratio. I suppose it could happen with more power as well...
It's all about clutch fill time vs how fast your rpm is climbing.
IIRC there are a couple options to remedy.
1. Command the shift at a lower rpm so the clutch has more time to fill...
2. Enlarge a hole in the valve body separator plate to allow the intermediate clutch to fill more quickly.
Keep in mind, the 1-2 factory aluminum accumulator is known to wear out quickly on early transmissions, if yours is a 2003, it may have the bonded rubber already. If you're pulling the pan, it can be checked and or replaced with a bonded rubber replacement without dropping anything else.
I found the TCCoa forums (Thunderbird car club) has a wealth of information on AODE/4R70w mechanical function, issues, troubleshooting, rebuilding, and modifying.
https://www.tccoa.com/forums/automatic- ... sions.990/
Thanks for the information. I always appreciated the Supercoupe guys since my first one (95 auto SC) I purchased a 90 5 speed SC which was even more fun but those cars got me hooked on PD blower boost! I’m going to work on tuning the electronic control end before I drop the pan. I’d like to avoid mechanically altering the trans/ shift kit
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 05, 00:26
by m-barans
decipha wrote: ↑2021 Jul 03, 20:35
No need in doing any of that just simply kick up the 1-2 as stated in the previous post
So I believe I found the TV pressure 1-2 shift table. Looks like output is PSI. I’m guessing I should add maybe 5 in the areas with higher TP rel. Maybe blend that in the table so it still ramps nicely? I will give that a try and see how it improves and report back. Thanks
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 07, 15:31
by 034v
In the TV tables, 650+ TP make 99.
Max TV scalars are around 95
No less than 10 so you don't get drop-out
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 07, 15:46
by decipha
No, absolutely do not do that as it will bang so hard you'll eventually destroy the transmission and or break stuff.
Most marauders I put the 1-2 shift pressure at around 30 psi. If its boosted you can kick it up in the 40s. Much more than that and you'll need an MRI and a neck brace if you manage to keep traction.
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Jul 07, 16:12
by 034v
decipha wrote: ↑2021 Jul 07, 15:46
No, absolutely do not do that as it will bang so hard you'll eventually destroy the transmission and or break stuff.
Most marauders I put the 1-2 shift pressure at around 30 psi. If its boosted you can kick it up in the 40s. Much more than that and you'll need an MRI and a neck brace if you manage to keep traction.
Ah.. nevermind lol. Not on them. didn't fully read it was a Marauder. my bad.
I was thinking Mark VIII without a Jmod.
Re: Late 1-2 shift intermittently 4R70W
Posted: 2021 Aug 04, 00:11
by m-barans
Ok, thanks for the information. I made some changes to the 1-2 shift but not really finding the results so I will investigate the mechanics of it after I get the car running again. The 03 cobra eaton needs a freshening up (noisy rotor pack) so she is disabled for the time being. Updates to come