After rebuilding my transmission, using a tci pro super rebuild kit (1985 700r4 by the way) i seem to be running into some issues. I have the transmissions on a dyno right now, so i have not put it back in the car yet. The only electronics on the trans are for torque converter lockup.

I having a "second gear start", and the trans will not downshift or upshift. The only way to get another gear is to shift down to manual Lo. I do have reverse.

on top of that, Line pressure is about 115 psi in second gear, and 145-160 in manual Lo and reverse, all at about 800 rpm.

lastly (for the problems) I have no pressure going to my pressure taps, for 2nd, 3rd, and 4th gear pressures. Before reinstalling the checkballs which were removed for the shift kit (i was having the same basic issues so i returned the transmission to factory style for diagnosing purposes) I had the same issues, but i DID get 2nd gear pressure at about 780rpm, which is weird because 2nd gear would not slip at all at 700 rpm when 2nd gear pressure was at 0.

It is not slipping in any gear, and all the checkballs are in the right place ( I am not sure about checkball #8, which is not located anywhere in the diagrams i have seen) I know i have everything torqued correctly and the gaskets are in the right place. I do have great fluid flow with no bubbles or irregularities.

If anybody has any ideas, or if you can point me in the right direction, let me know. I have had this thing on and off the dyno about 4 times now, and I am getting quite frustrated. I have attached the fluid diagrams which include manual 1st and 1st in drive (because i only get manual first and not 1st in drive).

 

Park, Part throttle downshifts and modulated downshifts (third gear position)

 

Nuetral, manual second, and Drive (no tcc)

 

Detent downshifts (in second gear), drive 2nd with tcc

 

3rd with tcc

 

I also have no t.v. boost and no significant boost of pressure in reverse.

 

bump

 

i know it sounds stupid so it might not matter, but i know in my boss's chevy 2500 which has the 700r4, and his wouldnt shift out of 2nd gear, he took it to a shop and they said it was a bad spedo cable, but the spedo worked, sooo i was kinda confused but just said alright, wtvr its working now. so ya that really doesnt answer anything, so i kinda got off topic.

But im guessing u have checked the locker, maybe its bad. what kind of shift kit did u put in the trans? did it require any drilling of the valve body? if so maybe u drilled to far. but hey u seem to know what your doin, wish i could help out a little bit more

 

yeah i dont even have the trans in the car. It is on the dyn oright now, and that is where I'm having troubles. haven't had it in the car yet.

As far as the shift kit goes, I didn't drill anything in the valve body, just the separator plate to copy my old one, didn't drill anything out bigger. Just threw out a check ball here and there, and removed the spring in the m.t.v. upshift valve. also replaced the spring in the pressure regulator valve in the oil pump. other than that and stiffer springs in the accumulator (which i beleive just soften the application of the band and/or clutchpack) there were no other modifications to the hydraulic circuit.

one other person came up to autozone (where I work) and asked me if i wiped the valve body off with a shop towel. And stupid me, i did. As if it makes me seem more innocent, it was a brand new clean towel. But I may try to remove the valve body and clean it.

What would you suggest to clean the valve body? Brakleen? carb cleaner? soap and water?

Thanks!

 

The only thing i could think of right now would possibly be a stuck spring or something out of place just the slightest bit, their tricky like that, had a buddy who tryed rebuilding his and had to redo it 3 or 4 times before he gave up, first time he did it he had all gears for about 4 miles then something happened and he had to drive it all the way home in reverse haha. but if i was u i would just use brake cleaner or carb cleaner and just let the valve body air dry, possibly the towl couldve got hung up on something and bent it a slight bit.

 

After cleaning the valve body, and air drying it, reinstalling it with the old separator plate (in hopes that it may have just bee a problem with the new one) and trying it again, I still have NO change.

I also pulled out the new 2-4 servo i put in (which is the corvette style), and replaced it with the old one with new seals. Put it on the dyno again, and STILL NO CHANGE!!

I am getting very frustrated with this. I have checked all the valves in the body and they are move freely (none of them are stuck). My next step will be to, again :remove the oil pump, and inspect the inside. disassemble the input clutch housing (one possible cause for a 2nd gear start is a sprag clutch installed backwards). I'm about 95% sure I didn't even mess with the sprag clutch, but I'm going to check it just in case.

Any other ideas folks? Are there any transmission experts on here or not?

 

I tried the trans on the dyno with a new 10-vane pump (just the new rotor, vanes, and seals. still using old face and body). First go-around, i had the exact same issues still. After letting it set for the night, i tried it again in the morning to show someone what it was doing, and I had completely different issues.

This time, pressures are too high in park and nuetral. Revers is at 200, park-160, nuetral-160, 2nd-120, Manual lo-95. still will not shift into 3rd or 4th, and still ahve no pressure to my line taps (with the exception of main line pressure)... All of these pressures were with no throttle cable connected. We can not seem to get any significant pressure change when pulling on the throttle valve cable.

looked at pressure regulator valve, and one of the lands has been ground off. This land would separate line pressure from converter feed pressure. could this have any affect on governor pressure or throttle pressure?

 

have u ever used this trans before? or is this something u bought that needed rebuilt?

and its possible that the pressure regulator valve could be part of your problem, but my question is wat ground the land off?

 

Yes. I am the second owner of the car (after a 55 year old elementary teacher who drove the car like it was a cadillac), and it had no problems other than some slipping when shifting to 2nd gear. It had 240,000 miles on it without ever having a rebuild.

It definitely looks like it was ground off by someone when they put in a shift improver kit. The lady who owned it never raced it or anything, so I don't know why she had a shift kit put in it. But I have had the car for almost 10 years now and have had NO transmission problems, which leads me away from thinking that the ground-off valve could cause these issues.

So to answer your question, I have had it for a long time.

 

dang, thats alot of miles with no rebuild on a trans with a shift kit, very impressive.
And your right, if its been like that for 10+ years and it had no problems its not gonna cause the problem now.

 

and with everyone on this forum im surprised no one else has chimed in. Where is everyone at?!

 

You did not take the forward sprag apart and forget and install it backwards.

 

I checked the sprag, and it is installed correctly, and the valve inside the governor moves just fine... I sure wish there was a pressure tap for governor pressure!!

 

So I was looking at the band, and I have another idea of what could possibly cause an issue with shifting. The new band that I have installed seems to be very tight on the reverse drum. It will not let the revers drum turn just using my hand. The old band seems to have a lot more free play and allows the reverse drum to turn freely without the band riding on it so firmly.
It could be possible that when manually shifting into 1st or reverse the pressures are overcoming the band (which i would imagine would wear the band down extremely fast). Could the force that the band is applying just from having too long of a servo pin, cause the transmission to not shift into 1st or 3rd automatically?
Could this new band that comes in the TCI kit require me to grind the servo pin down a little to allow for the extra clutch material?

I went ahead and ordered a new transmission to put in my car so I have something to drive.

But when i finish up with this one, I will be selling it (considering i get it fixed). Let me know if you will be interested in the near future!!

 

thats a good possibility, worst thing u can do is try and have it work, since u already have another trans on the way i would say go for it and grind a little material off the servo pin and see what happens, maybe put the other band back on and put it on the dyno after u shave the pin just to see what it does, then put the new band back in and see if it works. alot work but hey do it when ya have the free time

 

and what would u be asking for the trans when u are going to sell, is it off a carbed camaro or tbi

 

It came out of a 1985 firebird, with a 5.0. Carb. It has a tci pro super rebuild kit, and i can build it for how hard you want it to shift. stock, mild, firm, or hard shifts. but I'll be asking $600 after i get all the pressure right and get it to shift at the right rpm on the dyno.

Also, this is being done at Pittsburg State University, so there are profession instructors wtching over, making sure i don't do anything dumb. Still has a great torque converter with no problems.

Let me know if you are interested. We can talk about it.

 

very interested. im in ohio, dayton area. Maybe we could do a trade and cash. My 700r4 from my 92 camaro, stock. for yours and some cash? just throwin that out there

 

The only things I would be willing to trade for are- Fourth gen rear axle (differential, brakes and all), an edelbrock intake manifold, and a cam and lifter kit) I don't need another transmission. But let me know if you have anything like that laying around. Thanks!

 

actually i just might have a 4th gen rear end with the disc brake set up that i can get my hands on

 

That would be excellent, cause I would prefer that over anything. More specifically, I want a 3.42 or 3.73 ratio. As long as I can put some new pads on, fill the diff with filuid, and bolt it in, I would be happy. ]

Must obviously be in good condition, with the appropriate proportioning/metering valve.

Let me know what you find out!

 

will do, was going to get it and put it in my car but i rather get a new built trans instead of me having to fuss with mine

 

Well they just unlocked the Kansas Tech Center (which is where I'm working on my tranmission) a couple weeks ago, and I'm hard at work. It's back on the dyno and ready to be tested with a new band. The new one that came with the rebuild kit was gripping the revers drum too tightly, so I was thinking this may cause the transmission to not shift into 1st, or 3rd automatically. I can get first if I shift down to Manual lo, which may just be overpowering the band and causing it to slip which would allow 1st gear. We'll try the new band and see how things work. Wish me luck!

 

Have you checked the clearance on the servo pin ? also there is a encapcilated checkball in the bottom of the servo case that wears out and burns the band and the 3-4 clutch pak you remove the checkball and replace it with a core plug. Ive seen a few shift kits or i should say shift correction kits like ones made by gil younger that cover a lot of problems that the 700 r 4 had like that you are having.

 

did you ever figure this out? I have the same problem.

 

I still have not figured out my problem. What kind of checks have you performed? are you using a dyno or installing in a car? what year and everything? How about some background info on your transmission, used, abused, slipping, lady-driven, did you rebuild and have these issues or did it just start having these issues? we should work this out together if we can, 2 heads > 1.

 

What happend with mine was, I started off from a stop sign and it slipped then went into a neutral state. I down shifted to manual 2nd and it was fine. I tried low one and it worked. Just no movement in drive range. I pulled the trans and took apart. Found no problem with the forward sprag or and clutches. I did see some metal in the servo area. The car is a 85 model with the 700r4 with 103000 original miles. I have resently installed a L98 vette engine with alot of mods. She is running around 350 hp. I bought the TCI streetfighter rebuild kit but I really want to know what was causing this before I put it back together.