I was looking at the new car craft and read an article on tv cables. They say the throttle valve spring can become worn after thousands of cycles, will no longer respond to part-throttle inputs, and the pressure may not match the engine's output. No amount of tv cable adjustment can correct for a worn spring.
They go on to say any increase in torque output will probably damage the trans due to insufficient line pressure to handle this torque increase.
Basically old trans with old tv spring getting alot more torque than it's used to will probably go out alot faster.
There's details on how to do a pressure test and all that. it's the jan. issue of car craft.
if i manage to find a 3.4 and replace my 2.8 i'll probably do the test or replace the spring and cable.

 

just get a manual valvebody and then you dont have to even worry about the TV cable.

 

Is there a spot on the net to read the artical? Im thinking mine may be warn(200k mile car)

 

it might be on the car craft site. i don't know what their site is like. If i wasn't tired and about to go to bed i'd scan it and post it or something. I'll try that tomorrow maybe and see how it works

 

It simply comes down to the massive increase in torque generated by the installation of the 3.4.
If ya replaced the 2.8->3.4 engines & used same old worn spark plug wires, the "newer installed" engine would still peform poorly. Same idea on the tranny's.
Prior to swapping engines, whatever part was marginally weak before will soon fail after the engine swap mission.
TV Cable adjustment, if not distured during the swap & the tranny worked/shifted well, will be "proper" again.
My tranny failed after my 3.4 swap. It was due to clutches between 3-4. And my heavy right foot usage. I SERIOUSLY enjoyed the new found torque!
I added fresh tranny rebuild & new tranny mount, my problem was solved. Never was the TV cable disturbed during the engine swap, before or after swap or tranny rebuild.
I've read that article & would like to "play" but, the car is working/shifting perfect, why bother?
I have stronger engine-tranny/vehicles for "fun".
I've driven TOO MANY YEARS with poorly performing trannys. My 85 Firebird tranny finally works right. What a treat. Has for over two years since the rebuild, too. I drove over 8 years with a 700R4 tranny that was fu(ked up, so bad, I even went to small claims court suing that tranny rebuilder.

 

I'd hardly call the 3.4 "massive torque" Karl! After all, the 3.1 got 180 or 185 ft lbs (depending on source). The 3.4, if I recall, only has 15-20 more ft lbs than that, at 200 ft lbs. Which is roughly the same amount of torque difference between the 2.8 and 3.1.....

 

It's also been in the GM Service Manual since the year your car was made... http://www.helminc.com, and since the 700r4 came out on the market (1983) it's been in the books. Also look to the ATSG service manual from http://www.naparts.com or http://www.atsg.biz

 

It simply comes down to the massive increase in torque generated by the installation of the 3.4.

Prior to swapping engines, whatever part was marginally weak before will soon fail after the
engine swap mission.

MOST of us here, buy/bought our Third Gens in used shape. Aged, dented, dead, dying or on life support used 3rd Gens. We bought the underdog, the V6, too!
The drivetrain of our purchased rides tends to be on last legs or has some steam, but there is a weak link.

When ya step up in power output, one of those weak links is exposed, dramatically.
As purchased in my Firebird, I had a weak 2.8 that I made run, again. The tranny in my instance, was "rebuilt". And as that 2.8 was brought back to life, tranny did work.

I'll quote from Car Craft...
"The Number One cause of 700R4 failure is the loss of the OVERDRIVE CLUTCHES (exactly what happened to me, too). This is USUALLY CAUSED BY A TORQUE INCREASE without a pressure (adjustment) rise in the transmission."

I also increased the usage of my new found torque (the 3.4 swap & heavy right foot), thus accelerating the failure of a "weak, poor rebuilt" tranny.

My torque increase was a gain of atleast 100 Foot Pounds (dying 2.8 to a strong healthy 3.4). Very respectable numbers (without a power additive) & a VERY healthy gain for only an engine swap.

I did not adjust the cable after my 3.4 swap. To me, adjusting a TV cable on a weak tranny that was poorly rebuilt, ain't gonna solve many problems, only accelerate wear & breakage. After my 3.4 swap, my Firebird tranny failure was in the 3-4 clutches (overdrive part). The rebuilder told me he "upgraded tranny accordingly" and the Firebird tranny feels & shifts like he kept his word.

This Car Craft article is excellent & execution should be encouraged, if your subject is a healthy, recent upgraded well rebuilt tranny.
Aged trannys, should have this done during the rebuild.
Many times, we as car crafters have discovered, that there isn't a magic pill for prolonging life in aged, poorly maintained, previous owned, mechaincal parts.
IF there was, there'd be no mechanics!

 

When you say that the 3-4 clutch goes out, do you mean that the tranny just won't try to shift into 4, or that it tries to but can't get 4th.

I've noticed that after swapping in a healthy, somewhat built 2.8, my tranny doesn't like to shift into 4th until about 43 mph, which is amazingly annoying especially since the fastest that I go regularly is about 35. I think if it would drop into 4th all the time my mpg would skyrocket.

 

When the clutch goes out, the car won't shift to that gear. Period. It won't try at all. It'll just be like driving in 2 or in D, instead of OD.

When the clutches start to wear down, you might notice abnormally soft shifts or other problems. Delayed shifts are more generally caused by TV cable maladjustment than by clutch wear.

 

Something i have been considering too though for the last 6months of driving had been a tranny rebuild. If or when I find a 3.4 and pull the motor, rebuilding the tranny also was something i think I need. Over the last year the tranny has slowed slightly in shifting I think, shifts a little to early in the rpm range unless I floor it, and occasionly starts shifting up and down really quick. Only done it once or twice in last 6 months but never in the last 4 or 5 years. Or maybe it is just the cable, I just can't do anything about it yet cuz the car is still being shipped from Germany

 

To cure a lot of my shifting problems, I lubed my speedo cable. I also used the wrong grease (axle grease).
IF ya do this use only WHITE GREASE!
I'm gonna seek out a new speedo cable & swap that in.
The tranny convertor locks at 35 MPH (3rd gear) & 45 MPH (4th gear lock up).

 

I didn't think Redraif's TV cable would need adjustment after the 3.4 swap either, but it was slightly off for some reason. Check it and reset it, it only takes a few minutes and could mean life or death for your trans! In her case, the spring is new (part of the Transgo Shift kit) so that wasn't an issue.