Ok, just had my trans rebuilt with some upgraded parts, one of those being a billet 2nd gear servo. I should have left the corvette servo, but I thought oh what the hell, might as well upgrade that too---lol!

Bottom line, the 1/2 shift under moderate to heavy load is too harsh for my liking and I feel it will lead to parts failure or excessive wear long term.

The accumulator isn't blocked, hole in separator plate isn't opened up, etc. Basically, my builder wanted to get more capacity (wide band, billet servo, etc), but not make the shift too hard. We didn't quite get there on the 1/2......

What to do??????

1. Tune the 1/2 shift table to reduce the pressures in these areas?
2. Install the corvette servo?

I'd like to do 1, but it makes me nervous pulling back the pressures like that.........

Trans has 225-230psi of line pressure during loaded conditions. Thanks.

 

What type of SK was used and also which servo?

 

Sonnax Performance Pack and servo. Basically, 95% of the parts is Sonnax stuff. Thanks.

 

Is that sonnax SK similar to the transgo hd2 , couse i also bought the sonnax 1-2 servo, now Im kinda 2nd guessing if I should put it in ?

 

I would say the Corvette servo is probably perfect for 95% of the applications out there imo. I should have left good alone....

Also, I thought the transgo hd2 kit was kind of aggressive as far as shift quality goes??? I think that is why you see so many builders that pick and choose different pieces and mods for "their shift kits".

 

So i will ask this age old question since chef vince is in here, how hard is "too hard" of a shift?
I am sort of in the same predicament, except i purchased my truck with a SK and have no idea whats done to it..(all i was told was transgo kit) It will chirp the tires 50-60% throttle and up, and pretty darn good wot obviously..
I asked my tuner to tone wot down a little bit, but now it just seems to have a long hesitation occasionally on the 1-2 instead of just the usual quick violent upshift..

 

I would be curious what he changed in the tune? Think he would tell you? Sounds like he added some torque management to the shift? Maybe extended the shift time a little? Hard to say---very interested though.....

 

I honestly have only installed one of these kits and the 1-2 shift was one of the concerns we had as well when we finished the install of this kit. There are a few things to look at that might be effecting the 1-2 shift. One would be line pressure when the shift happens. Also with that servo did the builder scotch bright the bore for the second servo d-rings and also the accumulator piston? Glazed bores and rubber seals do weird stuff with the function of pistons using rubber seals. Another thing to look at is the 1-2 accumulator valve and sleeve in the valve body to make sure its not sticking. Also make sure that the sleeve was not installed upside down blocking accumulator oil function. The easiest way to try to tone it down would probably install the factory 1-2 accumulator springs set ups in the accumulator housing and the valve body. If you want to try to tune it out with your tuning software I guess that would work as well. I'm going to send an email to a guy I know to see what his thoughts are here on your issue. Maybe Gregg will chime in here to give his expertise here!

I guess the real answer to that question is the point in which you start tearing stuff up! Then back off. IMO you are really after clean crisp shifts. However in some cases when running factory stalls this is harder to do because they do not dampen the shifts as much as higher stalls will. I feel one issue in trucks and tires barking is because you don't have enough weight over the rear tires. I know this sounds stupid when talking about a truck right? I remember years ago building a trans for a s-series truck and somehow the builder slipped in a vet servo. On the road test my boss said it barked the tires and was a little much for this truck. When we dug into it we found the servo. After changing it back to the 554 servo it was just fine! Being that this little truck is even lighter than yours they used a larger inner diameter 2nd servo to use less oil in it. Not sure if this answers your question here but I figured I would add this info. Vince

 

Thank you Vince for the feedback. I'll talk to my builder and see what he says on these items.

What is weird is the 1/2 shift actually firmed up after a hundred miles or so of driving. It's isn't harsh until you get into moderate to heavy throttle though. Maybe not harsh, but very very firm.......

Also, the trans has a tad bit of delay when going from reverse to drive (wasn't like that before). It's not much (maybe a second), but noticeable..... Everything seems to work great otherwise though. He wants me to drive it for a few hundred miles, then we'll pull the pan and see how everything looks and maybe make a few tweaks if necessary. Really cool guy willing to work with me.

He told me what the pressures were but I'm not 100% sure I'm conveying them correctly. IIRC, he said they would almost immediately jump up to 225 or maybe 230 off idle. They would taper off slightly to like 220 or 225 at WOT/high rpm. Does that sound right? Thanks again.

 

The pressures should not jump up to max psi without being past 3/4 throttle IMO. That might have something to do with your tune if you have one done that elevates line pressure. If this is the case set the force motor tables back to stock to see if it helps any. The reverse issue is kind of a normal problem for these units IMO. I think one issue to always look at is the inside of the reverse input drum where the cushion plate rides in the bottom of the drum. On used drums you will see marks in the drum where this plate rides. I feel that this plate in some cases sticks on the apply creating the delay. Another thing is if the bushings are worn in the drum. This might effect the oil pressure for the circuit when trying to apply the sealing rings and might contribute to this issue as well. One thing I have done for years is remove a check ball from the rear of the case in the low/reverse piston area. This is something builders have been doing since the days of the 700r4. I personally do not believe this will help with a park to reverse apply delay on a 60e but will help in a drive to reverse apply. Reason being in park the low clutch is already applied so we are basically waiting on the reverse input clutch to engage. Vince