Calling all 700R4 Experts!

[60case]

You need to get the TV cable right for a 700 to last. If you are having no down shift cable is not adjusted right. Also a 2-3 flare is the 3-4 clutch slipping. That is also a sign that the TV cable is not working right and very bad for the 3-4 clutch

[YoungPup1977]

When you changed the fluid a few months ago, most likely you had a bit of clutch material in the pan...maybe you didnt notice it and really didnt know what you saw in the pan but what you are describing sounds to me the 3/4 clutches has a bit of clearance from the clutches being worn down....common issue with 700R4's with possible TV cable not being adjusted correctly, the damage is done most likely and by adjusting the TV cable will not fix your issue with a flare into 3rd and possibly no 4th at all....

one of the reasons I tell people I will not change fluid on a vehicle in which its fluid has NOT been changed on a regular basis because most likely they are experiencing a issue (people wont tell you) and once I change the fluid and it leaves my shop....they start having more issues and someone always asks that question....who worked on it ?

Toss in new fluid on worn out clutches will not last long.... Good Luck !!!

[mister.freeze]

The fluid change was more for age than anything. The transmission had less than 1000 miles on a fresh build before sitting for 5 years. The fluid was dark but not smelly, and not gritty. It worked for 1500-2000 mikes after the change, making me feel like it was not a bad thing to change. I’ve experienced the fluid change making things worse first hand with the TH350 I had previously.

[mister.freeze]

Update: the cable is fine. Unfortunately, the replacement I got was the wrong one, so the old one is back in. It moves freely and doesn't bind. The fluid is darker than I think it should be, but it includes a bottle of Lucas Transmission Fix. I guess now I need to look under the governor cover.

[YoungPup1977]

Since this 700r4 did not come in this 1972 vehicle, do you know what the 700r4 came out of ? What was done to the 700R4 before it was installed into your vehicle ?

[mister.freeze]

Original core was out of an 89 Camaro. But that's all it was, a core. This transmission has been built and rebuilt too many times. The original build and installation was done by a shop and had to be rebuilt several times under warranty. It kept losing 2 and 4. It was good for a few years, then redone several times after that. This is the first time, though, that it has been behaving as described. Last rebuild was 500 miles before it sat for 5 years. I've been driving it now almost 2 years since that; daily 11.2 mile one-way commutes on city streets, rarely over 45mph. 4 could have been gone for the past 9 months and I wouldn't know. Only when I started getting second gear starts at lights did I start paying attention.

[mister.freeze]

FYI- Until a year ago, I had a 383 stroker pushing about 400hp. In the back of my mind, I always suspected that might have been a bit much for the transmission. Last summer, cylinder 3 cracked, and I installed a crate motor at about 290hp. If only I had the time and few bucks to put a sleeve and piston into #3...

[SeventyOne]

You updated...but did you change anything??

Same cable, same incorrect cable geometry? I'm confused what you did aside from the lucas fluid. Do you have 4th gear now?

[mister.freeze]

No actual changes. Still no 4th gear.
While I agree, proper geometry is ideal, this has worked FOR YEARS as is. I'm trying to find out A) what causes a loss of just 4th gear and B) if it's something I can live with given my driving habits or do I need to start investing in a new transmission?
Might anybody know if there's an Allison that is a direct replacement for the 700R4?

[kwmech]

You'll need to get off the tangent that "It worked for years". Yes it did, but not correctly by your own admission, and now you're having problems. YOU WILL BURN UP THE TRANS (if you haven't already) by not correcting the linkage and making the torque convertor lock up. Not locked up they create an incredible about of heat that destroys clutches inside the convertor. Having an incorrectly adjusted TV cable will burn up clutch packs. Fix it right or have that trans rebuilt once again, rinse and repeat

[SeventyOne]

Get the TV cable geometry fixed.

You asked for "700r4 Experts" and here we are telling you what to do.

I even sent a link to exactly what you need.

[mister.freeze]

Indeed, and thank you. I will fix the geometry. I’m not prioritizing that because without it, the transmission has in fact worked. Experience tells me that it would help my downshifting. Are you saying that it will fix my lack of 4th gear?

[kwmech]

Originally Posted by mister.freeze

Indeed, and thank you. I will fix the geometry. I’m not prioritizing that because without it, the transmission has in fact worked. Experience tells me that it would help my downshifting. Are you saying that it will fix my lack of 4th gear?

Not if you haven't burned up the clutches from improper adjustment already. But what do I know other than the fact I personally won't use a 700 anymore. Too finicky for me after rebuilding and messing with them for 8-10 years.

[mister.freeze]

Yeah, starting to feel that way

[YoungPup1977]

With everyone jumping on the TV cable setup, can any of you tell me the difference in the 350 vs 700R4 "bracket setup"....as I see the TV cable on this vehicle it can be adjusted by moving the piece on the end of the cable which tightens down on the the cable itself..... thats how the slack is removed, than adjust the cable by pulling up on the tab provided with the piece that snaps into the bracket...and you all know the rest on "HOW"

I just dont get it when peoples say they wont use a 700R4, fix it right and they last forever.....

so.....it doesnt downshift correctly, second gear starts......come on peoples what would you change next ? This is not rocket science..... OK, lets hear it....

[SeventyOne]

Youngpup - if i'm understanding what your saying, yes you can obviously get the 700 to run with the 350 bracketry and pull slack out of the cable but we both know the length of pull due to wrong geometry is what the real killer is here.

I mean looking at this diagram below i don't know how people either make their own bracket, or say they an run some other piece that just isnt right.

[YoungPup1977]

Thanks for the diagram and the time it took to get it but its not what he has....reference post 19 please and you will see what is going on....the cable can only go so far and it pulls straight out from the TV cable.....

Also, The kink in the cable has nothing to do with anything because its outside of the cable itself....

Look at the very end of the TV cable in the pic, notice anything, its how the slack is taken out of the cable....its got a set screw that tightens against the metal cable....

I am not saying the cable is adjusted correctly, I am saying this cable and bracket will work is all....

The setup in post #4 is a detent cable for a T350, so the OP of this thread mislead us on which setup he had....post #4 indicated his LOOKED like that but later posted a pic of his actual setup in post #19

[SeventyOne]

I'm not really sure what you're saying. Pictures all look wrong to me

How can the incorrect bracket, made for the wrong transmission be expected to operate and control a 700r4 correctly?

[YoungPup1977]

The ol 4th gear cometh back


QQ.........

[YoungPup1977]

[quote=SeventyOne;8256361]I'm not really sure what you're saying. Pictures all look wrong to me :lol

Pics are wrong and 4th has come back from the dead.

No mo experts needed.......

[jjzepplin]

Good luck.

[mister.freeze]

ALL- Thank you for your input and sharing your thoughts. I am by no means an expert, nor do I claim to be. This truck has, over the years, had transmission rebuilds by different shops in different places. After each, with the current setup, the transmission worked as advertised. I always just chalked up the failures to 1)my driving habits (young buck) and 2) a standard rebuild against my stroker motor. These days, though, I just commute to work, on city streets, under 50mph. The bracketry hasn't changed, nor was suggested until this thread, leading me to think that it worked in the past, so why would that be such an issue now? Failures traditionally were the loss of both 2 and 4, not just 4. My fluid change yielded no concerns, and the transmission was fine afterwards for 1500 miles. Doing nothing but commute, I lost 4th gear. So, just to eliminate it, I installed the geometry correction bracket. No result. At first...

Driving to work yesterday morning, I did not like how the transmission shifted: early and soft. No 4th gear either. So I did it manually that morning. On the way home, It seemed like I had a weak 4th gear!
So I tightened up the TV cable about 3/16". Better this morning. I'm at a loss. After all these years, and actual transmission people using the old bracketry, was this my problem all along? Did I have too much tension on the TV cable? What happened to cause the loss of 4th gear without even changing the old setup? How does it work now, when it worked months ago, by moving the attachment of the TV cable 1/2" aft of where it was? So confused.

Bottom line, though, is that 4th seems to be back. Should I change the fluid again to get the Lucas oil out or leave it?

[YoungPup1977]

Great thread. You fixed it. Got to see a pic of the change that fixed it. Change the fluid again and you might lose 3rd. Lol !!!!!

[mister.freeze]

NEW setup

[SeventyOne]

What bracket are you using now? Have a link?