MIKER

My transmission builder's name is John Goebel, he is from Hallsburg, TX. He is not your typical assembly line transmission overhauler. Building transmissions is not his full time occupation yet building high performance transmissions are his passion. He is an instructor at Texas State Technical College in Waco. His side business, Goebel Transmissions consists of a fully equipped shop at his home, complete with a, soon to be operational, transmission dyno. He also builds custom tailored torque converters. I have known John for several years and rank his integrity, and knowledge very high. As an example, John designed the TH700R4 trans-brake valve body currently being sold by Art Carr. Check it out at www.artcarr.com/catalog_right.html

I informed John of the popularity of the 700R4 topic on the Corvette Forum and I asked if he would be willing to answer a list of questions regarding set-up, performance, durability, etc. from us Corvette Forum members regarding 700R4 / 4L60 (4L60E and 4L80E questions are also welcomed). He told me that he would be glad to do it. I have seen various answers to questions and no answers at all to others. I know that many of you have questions that I have never even thought of so LET'S HEAR ALL OF THEM!
I will compile our list of questions and deliver them to him and I will post his response to the questions here on the forum.

Shark Racer

Is there any difference between the 700R4 and 4L60 designations? My assumption was that the later, stronger transmissions were the 4L60 and the earlier ones the 700R4.
Also, how much torque can a relatively built 4L60 take? (Like the BTO transmission.)
I already have my 700R4 and like it very much.
-Steve

RaC3R

I've heard/read about several C3 owners swapping out their stock tranny's for 700R4 units to use with their stock engine. Is is possible to use a 4L60E with a stock or modified L82 even though no computer is present? Or is it better to stick with a 700R4?

Ingar, Norway

First, BIG thanks to Miker and John!!
I have many questions:

-The "secret" behind the TV spring, why you use different types in
TPI/carb setups. And how to know what you have. Seems like they are
color coded, mine was red.
-What is the correct length of a red spring? (mine is 2.13")
-I have ca 0.35" plunger freeplay before the it hit's the spring and starts to compress it. Is this normal?
-I have measured the total TV pull length to 1.38" both at my TPI unit (still at the bench) and original Qjet. Still Bowtie say it should be 1.625". How come?
-Will running without lockup hurt the transmission?
-With ref to aux. coolers, can you run the transm. too cold?
-What's the best mods you can do to a 700r4 to improve longevity?


[Modified by Ingar, Norway, 11:32 AM 2/7/2002]

MIKER

I searched the forum and came up with a few questions from past discussion threads that I'll add to the list. I am hoping to help summarize some of the 700R4 related information so that every forum member that installs a 700R4 doesn't have to re-invent the wheel.
If you don't have any questions, only answers, feel free to post them.

MISC
Is there any difference in a 700R4 and the 4L60?

Does a TH400 really consume all that much more hp than a 700R4 or other automatic transmissions?

Generally speaking, which part most commonly fails in a stock 700R4? Which part most commonly fails in a high performance 700R4?

At what horsepower level would you recommend ditching the 700R4 in favor of different transmission?

“One thing to notice is that with the high horsepower rated ones a lock up stall isn't an option. Lock up stall = hollow input shaft = weaker transmission.” Do you agree with this statement?

It is my understanding that the input housing splines are weak. Do these fail very often? How do you prevent this?

Can the earlier model 700R4s easily be modified to late model specs for durability?

How much torque can the planetary gears take? What part of the planetary usually fails?

Is it worth the time and effort to modify the governor for shift points or best to purchase a pre-set unit from a vendor?

While driving, is it ok to “always” leave the transmission in the “overdrive position”? What is best for when driving hard? Why?

Can you suggest any particular service manual for the 700R4?

SHIFT
What advise do you have regarding shift kits? Any recommended brands? Install tips?

What are the pros and cons of converting to a full manual valve body?

Does a “full Manual” shift valve body increase transmission life? Why?

Is the procedure for altering 700R4 shift points by modifying the governor the same as it is for the TH350 and TH400?

How do you change the shift points?

THROTTLE VALVE
How does the throttle valve (T.V.) work? What are the variables?

What is your recommended adjustment procedure for the T.V. cable?

How much do transmission pressures vary from idle to WOT? What pressure values are acceptable for performance applications? Is there a recommended test procedure?

TORQUE CONVERTER
How do you find the stall ratings of the various factory stall converters? Will the OEM stall rating remain the same if they have been rebuilt?
What is the most common reason for failure in the generic (non-performance) remanufactured torque converter?

Is there any specific orientation for the torque converter to be aligned with the flex plate?

What is your preferred method of controlling the torque converter lock-up? Why?
What is the leading cause for torque converter clutch failure?

How do you know when a torque converter is seated properly during installation? What problems should you look for?

Can the torque converter be made to lock up in 2nd 3rd, and 4th gear? Is it best to only have it lock up in 4th on a high performance application? Why?

How many different ways are there to determine torque converter lock up timing?

FLUID
What is the procedure to check correct dipstick length (with pan off)?

Which outlet on the 700R4 is out and which is in?

What is the best way to determine the proper fluid level?

The theory is this: in a high mileage used hard tranny, clutch material is held in suspension and helps the clutch packs clamp. In a situation where those clutch packs have a lot of material removed, and you replace the fluid with new fluid (and new detergents) the tranny loses the friction modifying abilities of the old fluid...the detergent breaks down the varnish in the galleries and you end up with one or two possible end results: clutches that won't grab or a tranny that won't shift as the pistons in the valvebody don't move smoothly.
Is this a correct assumption?

When swapping a TH350 for a late model 700R4 equipped w/ electric speedometer signal, what is the best tail shaft housing to purchase for converting to mechanical signal?

Should transmission coolers be installed prior to fluid entering the radiator or after?
Can a transmission cooler be used without going through the radiator?
What is the acceptable operating temperature range for a 700R4?




[Modified by MIKER, 12:24 PM 2/2/2002]

Gary79

my 700r4 from BTO slips into OD sometimes at about 35 mph,how do I change that shift point?

mrvette

When I had my 700r4 rebuilt, the core was from an unknown source, supposed to be '88 up...any way to tell externally??...I had requested a Trans-Go kit on full hard shift....and got instead a Superior High Performance kit....from Superior Transmissions.....what are differances??? I also got a kickdown sleeve, that I noticed NO differance in operation upon my installing it...
I have a loose 'Corvette 2000 rpm' converter.....I want to go to a HD truck tite as hell converter for street driving...and to feel the shifts better, it's sloppy now.....tranny shifts, but converter slips, so no satisfying jerk unless converter is locked, which I can have happen in 2-3-4 gears....OR computer lockup at 50 mph.....but thing is IF I happen to do a WOT, the tranny insists on downshifting into 3rd gear....I don't want downshifting at high speed, how to eliminate that 'feature'.....

GENE

Ingar, Norway

gene:
the first digit of the type number tells the year.
Also the later units with 30spline and aux. valve body has 732 as the last 3 digits molded into the front cover. This is from 1987.

I'm writing an article on my 700r4 swap, look under technical at my page.

xfactor974

My tranny shifts like an old grandma, how can I make this thing chirp?

bryant080

1.Would you recommend swapping a stock th350 for a performance 700r4 from BTO or another company?
2.Are the performance gains really that much?
3.I have heard of people "bogging" out when at slow (35mph) speeds because of the o.d. what can fix this?
4.I have heard of a switch that can be installed to allow the lock thingy (cant remember the name) to be turned on or off in different gears to allow for different shifting depending on how much throttle...what do you think of these?
5.What kind of stall converter would you recommend for a lightly modified L82 with a 700r4?
6. what shift kit would you recommend using with this specific tranny? or does it even matter?

and thanks again to both of you for helping all of us with questions out.
-bryant


[Modified by bryant080, 10:15 PM 2/4/2002]

Ingar, Norway

I have found answers to two of my questions so I have removed them from the list:

-My line pressure is only 57psi in idle/park, but almost doubles if TV cable is disconnected from Qjet. What might this indicate?

This is how the 700r4 should work, and is a safety feature if the TV cable brakes.


-What's the correct 4th gear switch activation pressure. Mine opens at 30psi at the test bench, but it's not activated in 4th gear.

Solved it after hooking up a switch to control lockup manually. (See 700r4 article at my page).
Since it still didn't work I tested the vacuum switch.
(Had just shorten it during my earlier tests since it has always been ok before.)
Then I discovered that the inline filter had developed a crack causing too low vacuum to activate the switch. It was ok when I parked the car before starting on the conversion, guess the plastic cracked during the cold period we had earlier this winter.
The lockup really has a noticeable effect, stronger than on my TH350C.

So far so good, most problems have a natural explanation......

MIKER

I just finished compiling the list of ?'s and sent them off! I will post the response when I receive it.