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700R4, only shifts @ WOT

6K views 13 replies 5 participants last post by  Hotwire 
#1 ·
I have a 88 GMC Jimmy w/ the potent 2.8L V6 :mwink:

Recently it started intermittantly not shift from 1 to 2, manual or otherwise, had to blip the throttle a couple of times to get it to shift.

I got a Transgo 700 JR kit to hopefully elleviate a sticking throttle valve.

Here's where things get different: The trans has been rebuilt, so other hands have been inside this. It has a 82-86 valve body and does not have the external accumulator. No problem, just follow the directions to a T.

I have the 554 2nd gear piston, so I used the orange spring in the valve body, turned the one accumulator piston upside down, had a .471" throttle valve so I used the pink spring, etc etc. The only thing I wasn't really sure about is the instructions say absolutely nothing about the big check ball above the throttle valve, why is that? They show the location of all the other checkballs..

Now it will not shift unless I run the poor engine out to redline. I have all gears, reverse, drive, even goes into lockup after it hits fourth.

The only thing I can think of is I screwed up the TV bore trying to remove the inner bushing from the valve body OR I stretched the TV cable or whatever connects the tv cable to the transmission linkage.

Could I be getting low line pressure due to the cable? I had to re-use the spring that came out of the valvebody because it was bigger than the transgo supplied one, I had a #94 on the tv plunger so I used the supplied new valve and put the little brown spring inside the snout and the tapered spring over the snout, I also installed the little metal shim inside the tv spring.

I do not have access to a line pressure gauge and my wife is slowly plotting ways to kill me since we have to car pool, so any and all help would be gladly welcome. I'm just about to drive it like I stole it to a REAL transmission shop and leave it, I'm seriously worried about my skills. I have all kinds of 4L60-E manuals, but not one 700r4.

Thank you in advance,

Jeff
 
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#3 ·
82-86 VB...Did you also use the non-aux VB separator plate? There is a difference in this plate between the auxillary VB and Non Aux units. (pic shows the holes that SHOULD be present using your existing VB where it says plug)

The '88 you have *was* an aux VB trans right? Why the change?

Still a possibility that the TV valve has re-stuck, try and cycle the cable in and out quickly by hand a few times.
 

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#4 ·
Thanks everyone.

Everything that wasn't in the transgo kit is what was in the trans when I bought it. I've probably put close to 15-20k on the tranny, it just started gradually developing the 1st gear drop out. I figured I'd nip it in the bud before I pulled out in front of a semi and couldn't get over 30 mph. It shifted fine most of the time, it just developed this problem on me getting my dumbazz in there and fiddling with things...

I'm using the seperator plate that was in the trans, but what's screwing me up, the plate has C pressed in the valve body side. You know there's no way to reverse the plate.. The gaskets I have gotten show all the holes, double checked each time..

The truck is an 88, but I bet whoever did the "rebuild" just slapped another 700r4 back in place of the original. It does have a block off plate on the rear of the valve body.

I've pulled the valvebody twice so far, and I really couldn't tell you if it has those holes plugged or not. I'm almost 95% positive that the lower left one you have marked has a check ball. Not sure about the one on the upper right, would have to check my trans fluid sodden directions..

I may have figured it out, but still unsure why this is happening. I was looking around the net trying to find the answer, someone said to try the tv cable while the engine is off checking it's smoothness, then firing the engine up and checking again. I didn't get as far as firing the engine, BUT I did notice that the tv cable will NOT adjust w/ the throttle. I became a very skilled hand at adjusting it and I know it's not right, the cable will not detent out of the complete no slack position. What does that tell you? The cable wasn't stretched before I went into the tranny, I had my wife move the gas pedal w/ her hand before I slapped the pan back on for the 2nd time to make sure everything moved correctly, I thought I was golden.

Could I have screwed up the bushing in the tv bore and caused it to be too far back? I lined up all the passages when I reinstalled the roll pin, thought I had it right, that's about the only thing I can think of that would be off. I would love to drive the truck tomorrow, but I am not going anywhere if I can't get the cable to adjust.

I've been looking @ pics of TV linkages, I haven't seen one like mine yet. It has the plunger connected to the rod that goes to the tv cable, but it also has a little spring loaded pin, looks like a Tom & Jerry mouse trap, the pin goes up into the valve body and relieves a large check ball, what is that for?
 
#5 ·
Sounds like this trans was changed some where to an early design 700r4 as pointed out. Or mis matched v-body parts installed.

Check cable adjustment. Minimum adjustment is important.

Perhaps the TV sleeve was goofed up as you mention. Roll pin in wrong spot on sleeve?

Every TransGO instruction sheet I have read on the early year transmissions has the check ball 5/16" referenced .

I leave this check ball out on my builds.
 
#6 ·
Thanks Crosley,

These directions do not mention the 5/16" check ball at all, it fell out when I first pulled the valve body and it took me about 5 minutes to figure out where the heck it went, I'm glad it was larger diameter than the rest.

What's it purpose, why do you leave it out?

If I go back in there a third time, can I reuse the vb gaskets? Puhlease? They've been on there a total of 3.5 hrs and about 4 miles of driving. Would I be risking too much instead of showing up @ the trans shop a 3rd time for gaskets?

I'm assuming I screwed up the sleeve, just sucks that it's roll pin is on the top side of the vb.. :smash:
 
#7 ·
I looked at some TransGo sheets.. I was wrong , The 5/16" check ball is not referenced in these sheets I have.

That would indicate to leave it out.

The 5/16" check ball is the fail safe check ball. It puts the trans into fail safe mode when cable brakes or goes out of adjustment a large amount. The trans swill shift like the throttle is wide open if this check ball seats.
 
#8 ·
Hotwire said:
Thanks Crosley,

These directions do not mention the 5/16" check ball at all, it fell out when I first pulled the valve body and it took me about 5 minutes to figure out where the heck it went, I'm glad it was larger diameter than the rest.

What's it purpose, why do you leave it out?

If I go back in there a third time, can I reuse the vb gaskets? Puhlease? They've been on there a total of 3.5 hrs and about 4 miles of driving. Would I be risking too much instead of showing up @ the trans shop a 3rd time for gaskets?

I'm assuming I screwed up the sleeve, just sucks that it's roll pin is on the top side of the vb.. :smash:
Trans-Go has a toll free tech line,have you called them? one of the shops I serviced for years used only their kits and if a problem came up they were very helpful.
 
#9 ·
JeffB said:
Trans-Go has a toll free tech line,have you called them? one of the shops I serviced for years used only their kits and if a problem came up they were very helpful.
I appreciate the advice, but it seems I get better support through the very knowledgeable people on this forum and others, they're my first "go to" guys.

Also, I'm not getting out of the garage till late @ night, tech lines are shut down.

Slept on it last night, I'm going to look like an idiot and get vb gaskets for a third time and roll back into the trans fluid and quik dry. It's got to be the TV that's causing the problems, but I just don't see how I could have messed up the inner sleeve that much to allow 0 adjustment on the cable. Before I pull the pan I'm going to start the truck up and go through the motions w/ the tv cable to see if there is a resistance difference.
 
#10 · (Edited)
C-10 said:
82-86 VB...Did you also use the non-aux VB separator plate? There is a difference in this plate between the auxillary VB and Non Aux units. (pic shows the holes that SHOULD be present using your existing VB where it says plug)

The '88 you have *was* an aux VB trans right? Why the change?

Still a possibility that the TV valve has re-stuck, try and cycle the cable in and out quickly by hand a few times.
Alright! I love having a junk computer in the garage. :cool:

Both holes that you show PLUG are plugged, the left one has a check ball that goes up into the case, the right one is plugged w/ the plastic check ball that the trans go kit said to use, located in the bathtub in the valvebody. I have a document on the 700r4 I downloaded a while back, think it was from some school for ASE tech training, it says to leave the checkball out of the TV, so that's staying on the bench.

So yes, I'm covered in trans fluid once again, I'm going to go completely through everything I did to see where I screwed up. I also went ahead and purchased a new TV cable, installed it first, still no good. :spank:
 
#11 ·
OK, everything was installed properly in the TV circuit, BUT, the roll pin holding the inner sleeve (@ TV) is as long as the other roll pins, when I put it in, flush w/ the vb face, it's contacting the transgo throttle valve and locking it in place. :pain: How short should the roll pin be? The ones that are in the trans now are a rolled sheet metal design, looks like a rolled up newspaper. I picked up some roll pins @ Autozone when I got the TV cable, they're heavier gauge, thinking that could hold up to some cutting better than the rolled type.

Any advice?
 
#12 ·
Ok, my first post was kinda confusing on the separator plate.

Clarification, If your trans is a non-auxiliary unit then you NEED those holes.

These holes are in the TV area and is probably the culprit. So the separator plate is the screwup.

The pic is of an aftermarket TransGo plate. It's designed to work with all years of TH700R4's. They supply two aluminum slugs to plug those holes for use with th3 '87-93 transmissions.

Check over things real good now... You're running us short on VB gaskets. :D
 
#14 ·
C-10 said:
Check over things real good now... You're running us short on VB gaskets. :D
lol, yea, haha, if your supplier is located in Charlotte, then I reckon you're right. :pimp:

Back to getting this thing together. None of the roll pins I got from autozone will fit, so I'm going to modify the ones that came in the trans. :rolleyes:
 
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