Booty_Con

First let me state that I know very little about the inner workings of transmissions.

Mine is a 700R4 in a 1991 Camaro RS with 2.75 rear gears. I wanted to get it modified in such a way that it would have firmer shifts. I talked to a gentleman at TransGo who recommended the SK 700R4 Jr kit, a Corvette servo, and (if I remember correctly) some extra clutch packs between 3rd and 4th and a reverse intermediate boost, etc., all of which I wrote down.

I ordered the SK 700R4 Jr kit and the Corvette servo. The other parts, I was told, should be readily stocked on hand at any decent transmission shop.

So I take my Jr kit and corvette servo, and my list of other parts, to a reputable local transmission shop, tell them what my goals are for the car, and they agree to install everything for me. Halfway through the install, they call me and tell me that instead of installing some of the other parts on my written list, they recommend some other additional kit, the name of which I can't remember now. Again, I know nothing about transmissions, so I relied on their advice and told them to go ahead.

Now the transmission shifts nice and firm, and I like that part of the end result. But I also noticed the shift points now come later (at higher rpm) then they used to. I imagine they did it this way for racing purposes? But it really cuts into my mileage. I can be cruising around my neighborhood, only doing 25-30 mph and the engine must rev to 2600 rpm before it shifts up. Before all the changes it seemed to shift up sooner than this, and the rpm would stay below 2000 while cruising 25-40 mph.

So I take it back to the shop, tell them the shift points are too high, and ask if they can adjust the shift points back to where they were before the mods, i.e. closer to factory settings?

They look at the transmission and call me back and tell me that because of the mods/kits they installed, the shift points are now FIXED and can't be adjusted anymore. They didn't tell me before installing the additional kit they recommended that this would happen.

Can anyone tell me if the shift points were fixed because of the TransGo SK 700R4 Jr kit? Also, what part of the transmission determines where the shift points occur, and can this part be replaced? I'm totally out of my realm here. What parts and information do I need to be aware of next time?

Is there now no way to have my transmission "restored" to having adjustable shift points again? I still want to keep the new, firmer shifts ... I just want the shift points adjustable again.

Thanks for any help and advice .....

TZFBird

Your "shift points" are based upon line pressure. A certain amount of pressure is required to build based upon RPM. By installing shift kits, you are replacing springs in the valvebody that require greater pressure to overcome them. There is also the governor in the tail of the transmission. I am still unsure as to how this ties into the shifting of the transmission, but will hopefully understand it one day.

One thing you could try is double checking the TV cable adjustment. This is also line pressure related. Adjusted wrong and you will have low pressure which will burn up the clutches. Too much and it could cause what you are talking about.

Try wrapping your brain around this:
http://www.tvmadeez.com/article/index.php

I'd double/tripple check that to make sure that is not your problem. In my case that was my problem. I ended up rebuilding the trans, smoking it(50 miles later) from being adjusted wrong again, rebuilding again, found this writeup and now things are great.

Booty_Con

Thanks for that ... I've been trying to digest it over the past couple weeks. I did take it to a shop that checked the throttle valve cable; they made some kind of minor adjustment to it, test drove it, and told me it should shift and drive better now. It does seem to shift a little bit more efficiently than it did, but there is still room for improvement. If I ever win the lottery I will pay down all my student loans, mortgage, etc., and then go back to school to be a mechanic so I can work this stuff out for myself.

What do you think of this thread?
https://www.thirdgen.org/forums/tran...s-springs.html

They are trying to do the opposite of what I'm doing, but it seemed to have some interesting clues ....

John in RI

iTrader: (167)

Here's a look at the factory Shift points for your 4L60 Tranny:



Obviously now that you've modified the tranny your shift points will chage - but I would not expect them to deviate much from stock with only Part Throttle operation.

Sounds as if your TV cable could be out of adjustment as well. Re-setting the cable is VERY quick and easy; I would suggest moving the throttle lever BY HAND ( not the pedal ) when re-setting it according to the factory instructions. (And even manually moving it 1 more click past full travel adjustment. I've found the extra click 'out' was the best setting after reinstalling Carb, TPI, and TBI engine/automatics..)

Fast355

iTrader: (2)

Raising the line pressure tosses that chart out the window. Properly adjust the TV cable and make all shift point changes with the governor. That extra click out will signifigantly reduce the life of your 3-4 clutch pack. With a simple shift kit my WOT shifts went from right at 5K to bouncing off the rev-limiter at 5,800...I had to raise the rev-limiter to 6,000. My minimum throttle 3-4 upshift went from around 42 mph to right at 55 mph. PERFECT for the cam I was running though.

John in RI

iTrader: (167)

(Obviously ) The shift chart above is for reference only.

Been driving on 700R4's for over 20 years,... done almost every swap and conversion that can be done on Third Gens using other Third Gen drive-trains. I've never killed a tranny or had ANY problem after factory adjustment was made, then an extra click was added. ( I did install a dead tranny once, but that doesn't count. ) Using the factory procedure - In my experience - automatics have a tendency to downshift all the way from 4-2 when the pedal is floored at normal highway speed ( true in my experience after Carb, TBI, and TPI installations ) The extra click 'out' stops the tranny from downshifting all the way to second from fourth at 55-60 MPH. THAT will "significantly reduce" the life of the tranny AND the engine.

To each his own,........




Just about every source I've read indicates that the governor's primary responsibility is WOT shift points ?? ( AKA - Shift Timing )

"Do not attempt to adjust the shift timing with the throttle valve cable. The shift timing is controlled by the governor springs. For higher shift points at wide-open throttle, install lighter springs or remove one of the springs. For lower shift points at wide-open throttle, install stronger springs."

I'm no Tranny professional; I just know what has worked for me over the years. If the WOT shifts are OK, I would not suggest changing the governor.

Booty_Con,.... Here is some interesting reading for you:

http://www.73-87.com/7387garage/drivetrain/tvcable.htm

Davidgou

iTrader: (2)

Hey John, thanks for the link.

Booty_Con

Interesting link! The procedure they're describing is pretty much what I remember the second transmission shop doing for me when I took the car to them and described my problem to them. They made a quick adjustment of the TV cable (I even remember hearing it click as they did this), then they test drove it and gave the car back to me. They took pity on me I guess, 'cause they were kind enough to do this without charging me anything. Like I said, it drives a little more efficiently for me now, but I still think there is room for improvement in terms of getting the shift points closer to factory settings.

I don't know if the first transmission shop did anything to the governor, but I do remember the SK700 Jr kit coming with some springs that looked like the springs that come with the B&M governor kits, so maybe the SK 700 Jr kit did include modifications to the governor? (Wish I could remember the name of that other kit the first transmission shop also installed along with the SK700 Jr.) I am now wondering if I should just order a factory (non-corvette) governor and install that. I wonder if that is something I could do or would it be best left to a professional.....

Fast355

iTrader: (2)

The problem with adjusting the TV cable out is that it will not build line pressure the instant the throttle is opened. This can cause clutch failures (I drive heavier trucks/vans). It may not be as much a problem with the cars, but it potentially could shorten the life.

4-2 downshift is NORMAL at that speed....With a 2.73/3.08/3.23 gear that came in most of these cars, a 4-2 downshift would put you right around 4,000-4,500 rpm and would quickly zip you up to about 5,500. You never know when you need a quick burst of speed with the way people drive around here.

John in RI

iTrader: (167)

Swapping the Governor is really easy, Pry off the case ( take your time and don't bent it to hell ) pull out the gov,.. install the replacement. RTV the edges of the cover and re-install cover. Don't swap the Governor unless you install quicker gears.

The Gov on the left was removed from a 3.23( and lower gears ? ) tranny and the gov on the right was pulled from a 3.42 ( and higher gears ? ) tranny. The tranny I used in my RS was originally installed with a factory 3.08 gear and I put a 3.42 gear in the car. Once the 3.42 style gov was placed in the in tranny and the car was put back together,...... my WOT shifting is at about 4500-4600 RPM; The engine is a *almost* stock 91 TBI.





Unless the car is an L69, 85 TPI or 350ci the last thing you want it the tranny to do is dump you INTO any gear at 4500. Anyone that ever drove a LG4, TBI - even most TPI's - will tell you that they go NO WHERE fast at 4500 RPM. ( Why red-line the engine & watch the car next to you pull ahead while waiting for it to upshift ?!? ) 5500 shifts in MOST ThirdGens will eventually turn the engine into a boat anchor.

Booty_Con

Well I had the governor replaced today with a factory OEM 700R4 governor, just in case the original governor had been modified and was causing the late shifts. No change in the shift points, so that doesn't seem to have been the problem. Fortunately they didn't charge much. They also checked the TV cable (third or fourth time it's been checked), and no problem there either.

I found the list of other mods that were done to the tranny, and they include:

- 471 primary boost
- 282 reverse intermediate boost
- 1 extra clutch in 3-4 pack
- corvette servo

Would any of these mods cause the shift points to come later, at higher-than-before rpms? Would the 471 primary boost have something to do with line pressure?

Sorry for the noob questions, but like I've said before, transmissions are not my area of expertise.

RMK

Just out of sheer interest, would transmission fluid temp afect the shift point at all?

Booty_Con

Okay, so I just held my nose, took it back to the shop and had them replace the valve body thereby undoing whatever permanent mods had been made to the original valve body. Shift points are back to factory and I am happy. Only tradeoff is that it doesn't shift as firmly as it did before (even with the Corvette servo left in) but I am still much happier. Maybe I am too compulsive about my shift points.

What an experience this has all been .... :-/

And thanks to everyone for all their help and information ... it's definitely been an education.

AaronIROCZ

iTrader: (5)

If you ever want to tackle this project again, I would suggest talking to dana at probuilt automatics. I have been talking to him for every performance 700r4 trans that I build and every single time my customer has been very pleased with the results. He can be found here www.700r4l60e.com

Booty_Con

Thanks--I see his name a lot and he has by all accounts a sterling reputation. If I ever do start monkeying with my 700R4 again, I will try and get his advice.

krly79

Ok. Here is what you should have done. Left all the mods in the transmission that you had done. Buy a governor calibration kit from Summit or Jegs. Adjust your shift points using the supplied weights and springs by trial and error, until they are to your liking. The governor weight and springs are used in the following manner.

The lighter the weight installed, the later the WOT shift point
The heavier the weight, the earlier the WOT shift point
The lighter the spring, the later the part throttle shift point
The heavier the spring, the earlier the part throttle shift point

Only replace one weight or spring at a time. If you have a kitchen scale that will read in 1g increments then it will make setting your governor up a little easier because you can make a better choice in which way and how much you should go. Also try to keep the heaviest spring that you put on the governor on the heaviest weight that is installed in your governor. IE, if one of your weights is a 10g weight and the other is a 6g weight, and you have spring one and spring two installed. You would want to put the heavier spring between one and two on the 10g weight and lighter spring between one and two on the 6g weight. You don't have to do this, but it will make the trial and error a little easier. You can get your shift points right where you want them and still have it shift firm. Indeed, the higher the line pressure the later it will shift to a degree. DO NOT ADJUST YOUR SHIFT POINTS WITH THE TV CABLE!!! Your TV cable can only be adjusted one way and that it all the way out at WOT. MAKE SURE IT IS PULLED ALL THE WAY OUT AT WOT!!! If not then you are burning up your transmission and it will not last as long as it should.

WG383

Hello
maybe i am in the wrong place to ask this i need some heavy springs that someone might have left over from a Governor kit anyone? i have my wot where i want them but part throttle shifts still too high.

if i am in error asking this please forgive me
thank you

cosmick

As I just posted in your WTB thread in the classifieds, you can disassemble the governor, weld a bead to each weight, reassemble and test, repeat if needed. I'm usually doing the opposite, drilling the weights to raise shift points.
Stock LG4 governors shift around 4200, 6.2L diesels are around 3800.

cosmick

Dunno about adjusting the part-throttle shift points, I never cared as long as the WOT was correct, but mild engines should 1-2 at 35 MPH, healthy engines should 1-2 at 40, and overkill engines should 1-2 at 45, with a 700R-4 or 4L60E.