Happy to share the gory details, but cutting to the chase for a forum that’s been extremely helpful to me: on the advice of a local transmission parts shop, I installed a TCC valve that eliminated the relentless P1870 code on my wife's 96 Blazer 4.3 2WD 4l60e (182K), after the TransGo TCC valve failed to do so.

Perhaps this is old news, but since a forum search returned no obvious matches, I thought I would share this small fyi.

Okay, a few of the gory details…

I went to the shop (recommended by a good friend and 30-yr pro mechanic) for some AssembleeGoo (great for that one check ball that goes between the case and the VB plate!) and a couple of those hyperkinetic valve body clips many of you will know. I’d been bothered by the TransGo TCC valve (entry-level orange-box shift kit) because it dropped in the bore with no resistance at all, and I couldn’t see how in the world that was going to stop any slippage. It seemed hardly any tighter than the valve I’d taken out, and made me think I should have gone with the Sonnax TCC valve, despite the pricey one-use reamer it requires, because at least that made sense to me (ream the bore, insert the oversized valve).

So I asked the guy at the shop about it. He disappeared and returned with this FitzAll by TeckPak USA A74741Q TCC Valve, the packaging card for which is pictured in the attached files.

“Lotta guys are saying good things about this,” he said.
“Well those o-rings are something I can understand. At least it’s not just floating in there like the TransGo valve. How much?”
“$9.49, plus tax.”
“One please.”

However, possessed by an inherited demon that whispers something like, “do it the hard way first, that way you’ll still have the easy way as an option” (twisted and wrong, but some of you will know exactly what I mean!), I went ahead and buttoned it all up with the TransGo valve in it and ran it through two complete Drive Cycles. I just wanted to see if the TransGo kit would solve the P1870 problem for me as it has done for so many others, even if I couldn’t imagine how, given the wear in that bore.

It threw the P1870 during the first Drive Cycle, and by the time I’d gotten near home (about 30 minutes and 20 miles of driving round trip), the hard 1-2 shift was there in full force.

So I pulled the valve body again (yes, ouch) and tried this TeckPak valve. The o-rings make it tight, but with the help of a bar-clamp very carefully employed with strips of inner tube cushioning the contact points, it eventually squeezed tightly into place. I ran the truck through two complete Drive Cycles. The 1-2 shift felt perfect, even after the hour drive, and most importantly, the P1870 had shut its shrill and screeching trap.

Yes, I realize this transmission is compromised and will need a rebuild eventually. But it sure performs nicely now, and our family just needs a driver, so we’ll take whatever miles are left in this 4l60e. Bought new by my wife, the truck’s in great shape otherwise…

In any case, again just wanted to pass along some lessons learned. Sorry if it duplicates old news I wasn’t able to find.

In sum, the original “crescent moon” around the TCC valve in this VB was just like the one shown at about 1:30 in the video below. The TransGo valve was just too small to do the job. The Sonnax reaming would have done it in all likelihood. But this $10 valve bought over-the-counter at a local transmission parts shop has eliminated P1870, in this car, at this time. If you've got a P1870, it may be worth a try.

Thanks to the forum for all the education!


http://www.youtube.com/watch?v=RAKDW...eature=related

 

I too searched the forum on here for this same info but with no luck. You are the only other person that has inquired about the TeckPak USA A74741Q TCC Valve. I am interested in using it also but the tech guy at Teckpac (Roger) said that it will not work on some early 1995 transmissions that have the double sided nipple valve inside the valve body. Now my 1995 has the double sided nipple valve in it but does your 1996 truck have it too? do you remember what it looked like when you took it apart? I see in the video that 96 should have it too. and on Sonnax's web site it shows it to be used on 1997 too. the Teckpac instructions show the single sided nipple valve that started usage in 1998 and later...so can you help?

Also did you install the transgo shift kit too? if so which transgo kit did you use exactly? ( like part number) and how does it shift and perform now?

 

It's been in there nearly two months now, but I'm virtually positive my inner valve had a single-sided nipple, like the one on the TeckPak instructions. And I know it was stock to this 96 as my wife bought the truck new, and it was painfully clear no one had dropped that pan much less valve body prior to my adventure.

Others here will know better than I, but I'd ask the TeckPak guy exactly why it won't work with the double-sided nipple inner valve. And if there's no way to make it work that way, could you find a single-sided valve somewhere to drop in there, and use the TeckPak valve?

I did install the TransGo shift kit, SK 4L60E series L, orange box, everything on the instructions except the 2nd piston upgrade and the fresh spring in the 1-2 accumulator bushing, because I didn't feel comfortable removing the 2nd piston with the transmission installed, and therefore couldn't get the necessary code stamped on it to indicate the correct spring to install in the 1-2 accumulator bushing.

The transmission has performed very well since this work. The 1-2 shift feels just right, the 3-4 is fine if a little softer than I'd like, and I'm pretty sure overdrive has completely reintroduced itself after lying dormant for many moons. And the P1870 has not reappeared.

If you find reason not to try this TeckPak TCC valve because of the double-nippled inner valve, you might give the TCC valve that comes with the TransGo kit a shot. It won't work if your bore is as worn as mine was, but might otherwise.

Good luck!

 

Thats exactly what i was thinking of doing. finding that one sided nipple valve and using that instead of my double sided nipple with the new techpak piece. I did ask Roger at Techpak what exactly was different but he wasn't sure. he's guessing its the diameter of the valves. but can't confirm. So im not sure if this idea will work. just curious, do you still have the transgo valve that came in your kit and that you pulled back out ? Maybe you could measure the diameter on it for me to let me know if it meaures .440"


Also what do you mean by you passed on the 2nd piston upgrade? do you mean flipping the piston in the 1-2 accumaltor?

And do you still have a copy of the instructions that came with your transgo kit? thanks

 

I do and it does: .440 inch.

No, I flipped the 1-2 accumulator piston per the TransGo instructions, but I didn't swap in the new TransGo springs for the 2nd gear piston assembly. If I'm not mistaken it requires removing the 2-4 servo cap on the passenger side of the transmission near the wiring case connector, and I'd heard of some struggles getting that done with the transmission still in the truck. So I just kinda skipped that part.

Yes, I do still have the TransGo kit instructions. Did you need them?

 

Yeah i wanted to see the instructions so i can get a feel of what i would be getting into beforehand. and also see exactly what mods are done. it might not be worth putting the kit in just incase my tranny has other problems.... is there any way i can see or get your instructions?

When you flipped the 1-2 accumulator piston per instructions, did you also add some kind of spacer shim in there too that i heard maybe goes in there?
Oh ok so the part you skipped was taking apart the servo cover. yeah i heard the same thing that it is very hard to get access in the servo with the tranny in the truck. I think i would skip that to. however i think by getting in there to add the spring or tighten it up in there would get rid of that 2-3 upshift clunk that happens at light throttle. do you also have that light clunk too?
Just curious, what do you plan to do with that transgo valve that you have left over?

 

The instructions have a full complement of oil stains, but I'd be happy to send you a copy. For that matter, no plans for the TransGo TCC valve either, so I could send that along too if you want it. PM me with an address.

The only shim I see referred to in these instructions is part of the 2nd piston upgrade. The 1-2 accumulator flip did not require any shim.

My 2-3 shift is livable, but yeah, I wish I'd been able to put in the 2nd piston upgrade, and definitely will if I ever have to cave in and rebuild this transmission. Since the 4th piston is also under this same servo cover, I even wonder if my soft 3-4 shift might benefit from this 2nd piston upgrade; the extra shim, at least, would seem to affect it. The instructions only say this about the upgrade though: "These upgrades prevent 1-2-1-2-1-2-1-2-1 shuttle shift and FIXES 1-2 bump or bang at 20-24 mph. Makes tight short 2-3 shift and 3-2 kick downs."

So are you getting P1870s?

Let me know about the instructions and the valve.

 

Yeah that would be great if you could send me a copy of the instructions and the TCC valve too. Just make sure you put something soft around the valve to prevent scuffing and tape the valve to the inside of the envelope so that it does not brake free and fall out of the envelope. parcel post i think is the cheapest like about a $1. let me know. I will PM you my address.
Oh ok someone else had mentioned that there was a spacer involved when you do the 1-2 accumalator flip. I guess thats a different kit then. I think its better without spacers...
So you mean your 2-3 upshift is also clunky and noisey under light throttle? I have been asking around and some people have been saying in order to get to the side servo you have to remove the heat sheild that is up against the floor pan to get better access. Im not sure how easy that is though. I really want to fix that clunk if i could though....and i also have a 2-1 downshift clunk noise under very light throttle too....these are just some factory defects that can be adjusted im told...I think the extra shim from the kit in the servo would adjust the band servo pin on how far it goes down and how hard too. but im not 100% on that. Im not sure what 1-2-1-2-1-2 shuttle shifts are....1-2 bang,bump at 20-24 im guessing is when your TCC bore is worn and the computer puts full line pressure to compensate for the leak slippage and then you get that hard 1-2 upshift because of all that line pressure.
Im not getting any P1870 codes because my truck is the bastard year 1995 truck. I have an OBD1 computer but with a OBD2 plug under the dash. And thats the way it was since we bought this truck brand new. I do not show any engine dash light either. however when i scan the truck for codes using a EZ Link code reader under a generic mode I have 2 intermitent codes that are P700 and P1100 which are Transmission malfunction and Baratic something Manucfacture specific codes. I bet if i fix the TCC in the valve body my P700 would disappear....I pulled out my valve body for inspection because i started out as having tranny pump whine noise only when it wamed up. the filter was clogged causing low line pressure too. if you turned the truck off for 10 seconds and restarted it the noise was gone indicating it re-couped the fluid but then would come back after a few minutes. but i also lost my engine breaking in Low 1 with this. so i figure id inspect the valve body too while servicing the fluid and filter....and fix what i can and hope that i can avoid a rebuild since the tranny is hard to pull out because of all the 4x4 crap.....PM senton the instructions and valve... thanks so much

 

Got the PM, replied, will send the stuff asap, likely Friday.

Again, for my $.02: if this TransGo valve just plunks in as loose as the one you take out, I'd seriously consider finding a single-nipple inner valve and dropping the TekPack valve in there with it. I even wonder if it would work with the double nipple you have already.

This is the color of envy green for your lack of P1870s and SES light.

Anyway, good luck with it. Definitely post how it goes.

 

This is very interessting.
I have A Blazer LT 1997 with the 4l60e.

I have problems with 1-2 "hesitations" and lock-up works sometimes when the transmission is cold. When the lock-up is engaged it sometimes feels like it going in and out really fast.

I sometimes got hard shift 1-2 when the transmission is hot.
And of course P1870.

The oil is burnt, brown and smelly. I changed the filter and oil a couple weeks ago with no improvment. I only changed the amount of oil that came out when i removed the pan. There was no debri in the pan, just some goo on the magnet, that is a good sign, right?

Could this miracle valve save my gearbox?
At least for a while?

I found a kit on ebay with the valve, valve house gasket & pan gasket.
With shipping to Sweden about $70.

Is it worth a try?

Thanks,

/qsec