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The best 700r4 TV linkage, Monster transmission kit & 3rd accumulator checkball
I ran into some issues regarding a transmission I had built by a local shop and some things that were done that fried some components and made for some weird issues.
Car in question is a 1992 RS with a carbed LT1/700r4. Went from a stock high mileage LT1, stock transmission, carbed (4160 holley) to built 355 LT1 with 4175 holley spread bore and the 4L60/700r4 was rebuilt - I think it was the “SS mega” monster transmission rebuild kit.
I had been using the Holley geometry corrector and the typical associated bracket (and modified/lengthened) to accommodate the stock throttle cable, transmission shifted fine when the car was dropped off, the reason for upgrading it was for more of a safety net since I was going to be making a lot more power.
Well when I got the car back long story short they failed to install the geometry corrector or even address that it needed to be on the carburetor linkage. I suspect they removed it and left it off because it did not fit the spread bore linkage on the side of the carburetor. The transmission shifted violently and late and they tried saying it was due to it being built, etc. (mind you, Even before I got the car back, the holley bracket and geometry corrector was janky and not very rigid, and the WOT shifts were never the same as factory TBI/TPI, more on that later)
So I took it home and drove it and I still felt like there was something not right, I reinstalled the old 4160 holley with the geometry corrector, reset the cable, checked all the gears and when in D instead of shifting into 3rd it would start engine braking violently and locking up the driveline, but in OD it was like it was either missing 4th or skipping 3rd, but no engine braking, and was driveable on the highway.
huh, thats weird.
I bought a 700r4 rebuild book, watched a bunch of videos, removed the transmission myself , took it apart and found the 2-4 apply band was fried, the reverse input drum had black burn spots and was scarred from the band, and the engine brake /overrun clutches were also fried. Somehow nothing else was damaged, even the 3-4 clutch pack looked new.
I had it down to the bare case and had gone through with a master rebuild kit.
I didn’t find a whole lot of information on why this could have happened, until finally during reassembly I saw that the 3rd accumulator encapsulated checkball was removed and in its place was a plug.
the 3rd accumulator checkball to my understanding is what releases the 2-4 band and allows some type of venting.
I ordered one as it did not come in the master rebuild kit and finished reassembly of the transmission. Also, there was, if I recall, ZERO information about this encapsulated checkball in the case anywhere in terms of professional publications, only one or two videos that mentioned it online and a few mentions on some forums, and the Sonnax website has some theory behind it.
Finally, I found that at the end I was still having less than Ideal shift points. I measured line pressure, but it still felt like something was off, even with the Geometry corrector. The WOT downshift was not happening like it should from the factory, I was also having issues with the cable actually pulling the bracket back and out of adjustment during WOT. The typical holley bracket flange where it mates to the carb baseplate doesn’t really hold onto anything and its not very rigid so it can still be moved with enough force. I looked around forever until I found the Bowler Transmission setup. I bit the bullet, took a chance, & I installed the BT tru-shift kit and this kit although expensive, mimics the factory throttle radius arc required perfectly, and it was a one and done thing, just like all the publications said how to set the factory tv cable, this worked exactly like it should have and the setup is RIGID. WOT shifts are just like factory and drives like a normal car. There is no question this is the way to go with a 700R4/4L60.
Finally I have a few comments on the Monster Transmission kit. The big things
I noticed that really mattered were the hardened sun shell, and the 5 pinion planetary. There were a few springs in the accumulators that I suppose help with shifting and it did have a shift kit and a performance type servo. The waves/steels/clutches were all decent but If I could have gone back I would have probably went with Borg Warner high energy clutches. Also It did have a dual cage forward sprag, and a few other things in the kit, all and all a decent kit but I think its a little pricey.
The transmission now is not the weak point, it ran last weekend very strong, first time at the track and it ran a 13.3 @103. I have some carb tuning issues for sure but eventually I will get to it. Not bad for a low compression motor (motor is built for boost).
Moral of the story is DONT FORGET TO REPLACE / CHECK 3rd accumulator check ball in the case. It is amazing to me that they still sell the holley 700r4 bracket and geometry corrector because to my math it is still not acceptable or near the range of the factory setup — the Bowler Transmission tru shift is entirely worth every penny and finally the Monster rebuild kit is OK, but if there are other options I’d look into them.
Last edited by dereklicon; Jan 14, 2021 at 10:20 AM.
Re: The best 700r4 TV linkage, Monster transmission kit & 3rd accumulator checkball
Removing the 3rd accumulator check-ball capsule was a common thing that transmission shops did in the 1980s and early 1990s...
It has been considered to be a BIG NO-NO for the last 25 years!
Just to warn you, Monster transmission has gotten an extremely horrible reputation from members here and on LS1Tech.com
I would avoid purchasing anything from them in the future.
If you have to rebuild your transmission again, or go up in horsepower...
Remove and sell your 5-pinion planetary gears (they are inferior to the 4-pinion planetary gears).
I have 4-Pinion gear sets living with over 1,200 hp... the 5-pinion gear sets have failed (cracked) numerous times at half that power level.
Here is a post of mine on another forum on this topic:
Originally Posted by vorteciroc
Regarding the Planetary gears:
-From a load distribution standpoint; if two planetary gears are being compared, with the only difference being the number of pinion gears (metallurgy, dimensions, and everything else is identical)...
then the planet with 5 pinion gears would be better at spreading/ distributing the load/ force placed upon it and be considered stronger.
-However the "4L60E family" 5 pinion planets are made of inferior metallurgy, and are over all weaker than the 4 pinion planets.
To try and compensate for the inferior metallurgy; we increased the mass/ material surrounding the pinion gears... However it was simply not enough.
Look at this image of a 4 pinion planet. Notice the space/ air/ open area around the pinion gears:
This is a good thing, as it better allows lubrication oil to move/ spread about.
Compare that to this image of a 5 pinion planet:
The open area (around the pinion gear) had to be reduced to try and bring back some strength over all to the planet.
This however slightly hurts the lubrication.
On the rear 5 pinion planetary gear; we were able to add some lube oil slots to slightly improve the lube to the pinion gears.
You will see the OEM 5 pinion planets crack/ break way before the 4 pinion models.
The aftermarket 5 pinion planets are even worse... Do NOT ever purchase these.
There was absolutely nothing wrong with the 4 pinion planets... the only reason we actually made the 5 pinion gears was to save money (these parts were a cost cutting measure).
If everything else were identical... 5 pinion gears would be stronger.
But as I explained, the metallurgy/ casting is weaker... thus the planet as a whole is weaker.
You can use the 5 pinion planets... just not with high power.
I would switch to the 4 pinion planets in the 500 HP+ range... or if you have 4 pinion planets, just keep them.
The 4 pinion sets have survived over a year at 1,200+ rear wheel HP in one of my test vehicles... i can NOT say the same for the 5 pinion sets (I have broken the castings at less than half that power).
Re: The best 700r4 TV linkage, Monster transmission kit & 3rd accumulator checkball
Originally Posted by vorteciroc
Buy/ download a copy of the ATSG manual for the THM700-R4...
It will go over the third accumulator check-ball capsule and everything else in the transmission.
Yeah I looked into the ATSG manual, during the rebuild. The amount of information was frankly overwhelming but I did my best to try to locate the information regarding that checkball. Also, I am not surprised that it was something that was done in the 80’s and 90’s.... sounds about right....
Also one thing I failed to mention were that the spring clips in the input drum that keep pressure on the clutches were NOT reinstalled and that was another thing that I ordered and made sure to put BACK in the transmission. That was something I read in the ATSG manual and based on what that said I found it impossible to argue their importance.
Regarding the 5 pinion planetary, I actually found that information out as well after the fact and I am almost positive that I read that exact post of yours since it was literally only down for 2 weeks for the rebuild (full time job does not play well with hotrodding sometimes)
so yes when that trans fails I will be buying a OEM 4 pinion piece and installing that along with the Borg Warner Hi energy clutches. I doubt anything else would fail.... that trans feels rather stout now and I feel confident in taking it back apart a second time if need be. I dont have anything against monster however I would probably only buy some Sonnax and oem stuff next time I do a performance build on one of these (...if ever.)
