really hard 3rd to 4th upshift

[Chevy1925]

Ok so ive been fightin this hard 3rd to 4th upshift since i had mike build my trans. Ive done all the reseach i can here and at DP tryin to see what some people have done and had success with but nothing has worked for me.

Now here is when it does it: It will only do it when im on a high hp tune (mmlmms race tune or 450hp tune) when i go WOT throttle up through the shifts but int helower tunes you can still feel the "double shift", it jsut doesnt hit hard. Every gear will shift perfect accept when i go from 3rd to 4th. It hits so hard i think im gunna break something really soon. When it shifts its like a rubberband affect. it will shift hard then a few tenths of a second later its like it shifted again jsut as hard. almost like it hit 4th gear with an unlocked converter, then 2 tenths later the TC locks in but i know thats not the case cause logs show it staying locked in the whole time. Its such a drastic hit that you can see my vss on the logs show a 3-4mph increase then decrease then increase again them back to where it should be from jsut the hit.

Now ive tried different tuning from MMLMM, no difference. Ive tried different stock TCM tuning (both 03,02, and 01) no difference. Ive thought that maybe its cause im runnin out of fuel due to a bad CP3 but even with a lower tune you can still feel it, it jsut doesnt hit hard. Ive tried clearing taps numerous times, no difference. Tranny level is perfect when warmed up. spin on has been changed twice (last one was 3k ago). i have 20k on mike L.'s stage four trans and its done this since it was built. ive called mike (long time ago, bout 5 months ago) and he was thinkin its the tuning as i had a PPE at the time. When i got EFI Live it did it and MMLMM has tried different defuels with no difference other than makin the 1-2,2-3,4-5 up shifts harder or flair.

Is there something esle i could try im not thinkin of? I know i should just call mike but i know he has stuff goin on and it may jsut be something simple im jsut over looking. thanks guys, i really dont want to destry this trans or something else because of this HARD shift.

 

[KEVINL]

Welcome to the club I think its just the nature of the beast unless you drive around at wot all the time then it will shift good. If I am at the track and am doing a bunch of runs after the 4th run it usually starts shifting good

 

[Chevy1925]

Welcome to the club I think its just the nature of the beast unless you drive around at wot all the time then it will shift good. If I am at the track and am doing a bunch of runs after the 4th run it usually starts shifting good

but see it wont get better. i even click in tow/haul every time i do a WOT run so the alli keeps that part in memory. I think if you rode in my truck kevin, you would get whiplash cuase its pretty unsuspecting how hard it hits lol. hell ill give you a ride so you can see. It may jsut be that thats how they are but i dunno, it seems too harsh to be that way

 

[KEVINL]

Does it shift softer in regular mode

Mine shifted really hard for a while
The 3 to 4 shift in my truck is really slow too

 

[Chevy1925]

nope. jsut as hard in either mode. the 3-4th in mine isnt slowit will hit quick but its like it hits twice, and jsut as hard each time

 

[KEVINL]

How many miles on the spin on?

 

[Chevy1925]

3k

 

[KEVINL]

I don't know ZF-6 swap maybe

 

[Chevy1925]

I don't know ZF-6 swap maybe

i ahve seriously concidered it before but i like the alli too much lol

 

[Mike L.]

You don't want to keep resetting TAPs. Only reset the 3/4 and 4/3.

 

[durallymax]

3/4 takes awhile to smooth out. And its still usually one of the harser shifts. Just be patient, eventually it smooths out more.

 

[Chevy1925]

You don't want to keep resetting TAPs. Only reset the 3/4 and 4/3.

correct. forgot to say it was only those ones i was resetting. done it a total of 4 times since i got the trans from ya

3/4 takes awhile to smooth out. And its still usually one of the harser shifts. Just be patient, eventually it smooths out more.

well and see ive left it alone for two months at one point and did many many WOT runs in tow/haul on a high tune. probably had close to 3k worth of WOT runs in the two months. never seem to get any better.

 

[Mike L.]

correct. forgot to say it was only those ones i was resetting. done it a total of 4 times since i got the trans from ya



well and see ive left it alone for two months at one point and did many many WOT runs in tow/haul on a high tune. probably had close to 3k worth of WOT runs in the two months. never seem to get any better.

You also don't run any knockdown on pressure when the converter locks so the way you fuel it is critical.

 

[Chevy1925]

You also don't run any knockdown on pressure when the converter locks so the way you fuel it is critical.

so if im runnin the fuel rail down to 20k with a desired of 23k this could aslo cause the hard shift? not sure if you mean the defueling on shifts or if i run fuel rail down low. Why doesnt that affect 4th-5th? sorry mike, not tryin to question you at all, im just learing so i dont ask redundant questions :hug:

 

[03Dmax90]

My trans is doing the same, making me start to miss my cummins.

 

[MMLMM]

I've played with the tuning in this truck a lot. Seems to make no change. The same tune runs fine in another LB7 (built trans) too. We tried adjusting a lot. Hes tried TCM tunes too. I am at a loss. Short of someone else sticking a tune in it and seeing how well that works. It did it with the PPE as well though. He does have 35s and after I set the speedo and everything correct to that, it cleaned it up a hair, but it still shifts harsh. Some 5 speeds seem to have harder shifts, but this is a different type of harshness. I have another truck that will have a Mike L. trans in it (as soon as he can get off work lol) and it will have pretty much same tune, its on 35s and lifted as well. We'll see how it does. The other truck is in Florida on 35s and he has a SC trans and shifts flawlessly with same type of tune. Im not saying its something in the trans, Im confirming that its one of those things I cant track down in the tune.

James, I will dig thru the tune again over the weekend and see if I can come up with something more. I am buried right now and trying to get a few other guys handled tonight and tomorrow morning. Hopefully we can knock this out. I really hope its in the tune, but usually I can figure it out pretty easy and I have faith the tune I built is correct. Even after double checking myself a few times on this particular one

 

[Chevy1925]

I've played with the tuning in this truck a lot. Seems to make no change. The same tune runs fine in another LB7 (built trans) too. We tried adjusting a lot. Hes tried TCM tunes too. I am at a loss. Short of someone else sticking a tune in it and seeing how well that works. It did it with the PPE as well though. He does have 35s and after I set the speedo and everything correct to that, it cleaned it up a hair, but it still shifts harsh. Some 5 speeds seem to have harder shifts, but this is a different type of harshness. I have another truck that will have a Mike L. trans in it (as soon as he can get off work lol) and it will have pretty much same tune, its on 35s and lifted as well. We'll see how it does. The other truck is in Florida on 35s and he has a SC trans and shifts flawlessly with same type of tune. Im not saying its something in the trans, Im confirming that its one of those things I cant track down in the tune.

James, I will dig thru the tune again over the weekend and see if I can come up with something more. I am buried right now and trying to get a few other guys handled tonight and tomorrow morning. Hopefully we can knock this out. I really hope its in the tune, but usually I can figure it out pretty easy and I have faith the tune I built is correct. Even after double checking myself a few times on this particular one

Its no problem mike. i kinda figured after i had not heard back from you that your were pretty swamped. thanks for all your help in this, i really appriciate it.

If you guys want, i can post the logs of what the vss shows and my rpm differences when it shifts. its very drastic and shows up well. BTW i set the trans to my 37s and ecm to the 37s as well like we talked about doin and its a bit better but still has the hard bounce to it

Now i understand that i will get firm, harder than normal shift which i actually prefer but being a mechanic (which sometime gets me in trouble lol) i really dont think this shift is right. Id be more than happy to give kevin a ride or anyone else thats out here a ride so i can either confirm that it is jsut how these are suppose to shift or if it doesnt feel right to them either.

I do know that carter44 just got his tras built and his was doin teh same exact thing but he also still needs to let his trans learn the new hot tune off his ATS e-power.

I am lettin this thing learn as well. i put lots of seat time in this thing doin WOT runs on mikes hot tune in tow/haul with no avail. probably close to 500-600 miles before i try somehting different.

 

[03Dmax90]

When you figure your trans out, please tell me, mine is doing the same thing.

 

[Chevy1925]

i dunno if this will help any but maybe it will help show what im feeling. here are a log of both my race tune and low hp DD tune, both WOT from 3rd to 4th shift. Now granted these are on some older tunes mike made me but the new tune (which helped bring rail pressure from 17k up to 20k) still give the same exact hard shift. I can run these WOT runs all day on a high tune and the shift never gets any better (i tried doin it one day way out in the country this weekend). That was a straight 120 miles and 3/4 a tank of gas.

Is there maybe a solenoid i can check to be stickin or something in the valvebody i could check? i take some logs of the TCM tonight and post.

 

[Mike L.]

You're running 6 clutches and a wave plate in the C2 clutch. It should not hit hard. Try switching TCM's with another truck and see if it clears up and also if the other truck starts hitting hard.