I haven't posted on here in a long time, but I've run into a snag that I can't seem to unhook myself from. I recently inherited an '88 Suburban that's giving me some trouble. Yes, I know it's not an F-body, but the relevant drivetrain is the same as you might find in an F-body. Plus, I still drive my '85 TA every day, so I figure that gives me a pass.

The transmission that I'm having trouble with is a 700R4. The engine it's bolted to is a common TBI 350. I'm told that both are recently rebuild, although I don't know how recent. The issue is that the 700R seems to think that the engine is at WOT at all times, and the 1-2 shift comes in north of 35 mph. The 2-3 shift has the engine racing at a similar RPM. I don't know the condition of the rest of the truck yet, so I was unwilling to push it any further. Besides, if I remember correctly, the 700R won't shift into 4th if it thinks the engine is at WOT.

My first thought was that the TV cable must be either broken or disconnected, but I found neither to be the case. The cable was attached at both ends, and pulling on it yields a springy response. I tried disconnecting the cable at the throttle linkage, and predictably nothing happened. So then I tried zip-tying the cable all the way forward as if the throttle were jammed shut, and I still got no change.

When the transmission does finally shift, it's firm, quick, and strong. The truck surges forward as one would expect with a full throttle shift, so it's possible that it actually was rebuild recently. However, I've been a stick shift kinda guy up until this point, so unless changing the tranny oil and filter or changing the speedo gears will help, I'm stuck. The TV cable was the extent of my knowledge on automatics. Help please?

 

ur lucky disconnecting the TV cable and driving it didnt destroy the trans! dont EVER do that.

sounds like you need to adjust the TV CORRECTLY! a miss adjusted TV cable will cause too early and too late a shift. this is due to too little or too less pressure and the trans is being lied to due to the incorrect TV position.

follow this to the LETTER!

http://www.tvmadeez.com/article/index.php

 

If the tv cable is correct, I would look to the governor next.

 

Okey dokey. I followed the instructions for setting the TV cable to the letter, and I have no change. Is it possible that I have a broken TV cable or a malfunctioning TV valve? The cable still has tension when I pull on it manually.

What do I look for in the govenor? For that matter, where do I find it?

 

the cable could be broken, but most likely it would be bent to hard or something causing it to rub on the inside and this can even hang it up.

the cable should pull out and push in smoothly... no real slack or trouble pulling it. should be easy and smooth. if its hard to put, first make sure its the TV cable thats causing it, and then check the TV cable to make sure there are no hard bends etc. if no bends are present then i would look into replacing the TV cable. or pulling the trans pan and taking a look at the TV cable asslemby in the trans on the side of the valve body. the TV cable springs can wear out, and the TV valve can get stuck. only real way to tell would be to pull the pan and take that valve apart on the valve body.

for someone to be asking where the govenor is prob shouldnt be working on his own transmission. but its located on the back of the trans by the rear housing extenstion. its under the steel half moon looking CAP, its inside and is attached to the splined shaft with plastic gears, as the shaft spins the govenor spins and causes the weights to move outward (due to centrificual force) the govenor weights is what controls the shift points in the trans.

the stock 700r4s wont shift into 4th at WOT, due to the upshift valve being machined for 50% throttle it will kick down from 4th to 3rd. same goes for upshifting. there are aftermarket valves that allow 2/3=66% throttle(b&M) and TCI has one for 75% throttle. u can even modifiy the stock one for WOT 4th gear shifts.

 

What better way to learn than hands on? I wasn't even expecting to have the thing, so if I hurt it, there's no harm done. I'd already been expecting to polish my paint and body skills on it, so why not also use it to learn how the guts of an automatic work? So in that light, I appreciate your guidance. I'll check on the TV cable and valve integrity as soon as I get the opportunity.

On another point, why doesn't anyone tap their transmission pans for drain plugs?

 

i believe in the same moto... i always work with my hands but i do alot of research before hand. transmissions are to me more difficult than engines to build. alot more clearances and issues with checkballs, and it has to be DIRT AND ALL GRIME FREE. i mean any little metal shaving can cause many issues. transmissons are extrememly difficult but im sure if you have basic knowledge of cars such as engines, and how things work etc you could prob pull it off with a detailed transmission manual. haynes etc. still for someone to ask where the govenor is is prob not ready to tackle something like that, thats all. the manuals sometimes dont cover everthting so i hope you have a good memory and take lots of pics if need be. building my engine was cake but with my trans it was more difficult, mostly getting all the parts to seat fully, and knowing when something is fully seated in the clutches when u cant see them at all. Thats where experience or someone with it can help u.

to convert the stock pan to have a drain plug is not worth the hassle. most aftermarket deep/stock height pans already have them and they can be picked up for like 20$. I wouldnt stick a stock height pan on anything.... deeper ones will help with extra fluid when the trans needs it and will help it cool alittle better=lower trans temps.

 

Hmm... good to know about the pans. If I'll be pulling this one off anyway, I might as well pick up a pan with some extra capacity.

I figure that I've done a couple engines and a couple rearends, so now that I've got the opportunity, it's time to tackle what's in the middle. The only transmission I've had to play with around here for a long time is the T-5 in my TA, and even that was only messing with speedo gears. All that took was pulling the tail shaft.

Interestingly enough, my dad just bought a project vehicle that's got a 4L60 in it, so I think I'll go ahead and use this Suburban as a 101 course in auto trannys.

 

Update:
The TV cable is intact, and it's operating the TV valve without any apparent visual flaws. I was pretty disappointed to discover that fact, too.

 

it might look like its working fine but it doenst mean the spring isnt worn. this does happen since the TV spring goes throught like millions of compressions in its lifetime. everytime u step on the gas it will compress the spring... so how many times have u stepped or think the gas has been stepped lol... ALOT!. just saying dont just think its fine, it does happen.

i would now also check the govenor. make sure the weights move out freely etc.

 

Update:
I pulled the governor (despite the presence of a non-removable heat shield about an inch and a half away) and checked it out. The weights move freely, and the springs are springy. Holding the weights down and shaking the whole unit yielded an internal shaft that I can assume acts as a valve that moved freely. The weights actuated this valve-rod without problem. However, I was only able to see one o-ring on this internal rod, near the end with the green gear. It looked like it was possible that there may have been a place for another o-ring near the end with the weights on it.

There didn't appear to be any blockages or debris anywhere that I could see either on/in the governor or in the hole that it sit in inside the transmission. Installation and a subsequent test drive yielded no change from previous conditions.

What now? Pull the transmission and open it up to check for blockages? This is getting kinda fun.

 

Is it possible the rebuild was for an RV or heavy duty & towing?
Would that put RPMs in an un familiar range?

 

Not this un-familiar. The 1-2 shift doesn't come until 35 mph, which is ~4500 rpm the way this thing is geared. And it hits that shift point regardless of throttle position. If it was built to shift this way, I should find the guy who did it and smack him silly.

EDIT:
However, I did notice that once it finally grabs second, it stays there just like it's supposed to. It won't downshift to first until the truck slows to a crawl, which is something I've noticed on other automatics I've driven.

 

Well,I'm going to learn from this thread--seems like something to retain! Sorry but that's all I could think.
Also--
customblackbird--thanks for the link! I've seen it before but didn't save it--got it now!!
Good luck

 

I'm learning too. I haven't been this greasy this often since my last build. I'm starting to remember why I started doing this kinda stuff in the first place. It's like a hands-on mystery novel without all the murdering.

 

"...without all the murdering"!
You must have the gift of patience!!

 

I dunno if it's so much my patience as much as the fact that I'm working under a truck. That means little to no requirements for a jack, and acres of space to work. There isn't much that can frustrate you faster then the knuckle busting close quarters in our beloved F-bodes. I couldn't imagine the difficulty of trying to do what I've done thus far if I'd had to do it in the TA.

 

hmmm sounds exactly like the issues im having with my 4th gear apply. i just ggot off with DANA from probuilt (hes the man btw) I cant get into 4th gear untill 75-80mph but once its in 4th gear i can hold it in gear until like 60mph... i should be able to get into it at 40-45mph. Now this is one of the ONLY THINGS i didnt replace on my trans in the upgrade i just did, i had the trans rebuilt less than 30,000 ago and the guy did something to the trans where i couldnt engage 4th gear untill 55mph, stock it would go in at 40-45mph. I just said this to DANA and he thinks he knows the issue.

this could be the same issue your having. DANA said that the guy who built my trans prob took out the stock 3-4 valve pressure spring in the VB, and replaced it with a stiffer spring, this spring will take more pressure before it engages 4th gear. more pressure means more RPM from the engine to spin the pump to create enough pressure to overcome the spring!! AUGH!

On the VB towards the front of the trans (engine side) u will see 3 valves first is 1-2 shift valve, second is 2-3 shift valve, third is 3-4 shift valve (u must drop the VB to look at them/take them out) in these valves when removed are springs, some builders replace these springs to increase shift RPM/firmness but really it doesnt help at ALL! i would assume this person who built the trans has done this. replacing them with stock springs will solve this issue if its really your problem.

looks like we will both be getting on our backs and under the car to tear apart the tranny im not happy about his since i dnt have any room compared to u.

just food for thought

 

So it's transmission out and internal inspection time. I was both a little nervous and excited that you'd say that.

I wish you the best of luck with your dilemma. I remember how much fun it was just getting the autobox out of my TA when I swapped in the T-5.

"Okay, transmission's on the ground, and it still won't come out cuz the car's not high enough."
"Now what?"
"I dunno, the jack won't go any higher."
"You try and shove it out the back, and I'm gonna go see if the cherry picker is strong enough to lift the car from above."

Ugh. I don't envy you.