700R4 upshift issues

[mbood82]

Hey guys, I have an '84 GMC and it's giving me issues. I am hoping you guys can help, I have searched the web looking for answers and haven't gotten any.

The truck doesn't want to upshift until a very high RPM. First gear to second is really high and second to third is even higher, probably 45 mph. History of the truck below.

Truck at this point has a 350 with a 700R4 behind it. Both reasonably recently rebuilt. Prior to the axle swap, both worked as well as to be expected. I got the rear axle in earlier this year and it still shifted fine, so I'm assuming the gear swap (3.08s to 4.10s) didn't affect it. However, the carb started to act up so while I swapped the front axle I researched my options. Found an Edelbrock carb brand new for half price, bought that rather then rebuilding the q-jet. Now that the new axle is in, the transmission isn't shifting as it used to. My first thought was poorly adjusted TV cable but it seems to do the opposite of what it should if it was too loose and it certainly shouldn't be too tight. At this point I have pulled the pan and plan on going over the thing tomorrow.

Thoughts?

If it doesn't get fixed soon and cheaply I plan on just wheeling it until it blows up and swapping in an SM465 or NV4500.

Thanks for any advice you can give.

 

[tumbleweed1002]

Did you get the geomitry correction linkage when you bought the new carb? 700s are very sensitive to the throttel cable and if the cable is not adjusted correctly the trans will slip and burn up the clutches and bands fast. summit racing and jegs has the linkage corrector or if you want I have an extra one I can get to you either way dont drive too much or a rebuild will be in your near future.

 

[mbood82]

This (http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2D700203&N=700+115&autoview=sku) part?

I do not have that, however I bought a bracket that bolts onto the back of the carb that the throttle and TV linkages bolt to, the local speed shop said it was designed for this application in mind and was all I needed. I figured he was full of crap but at a local car show recently that was all anyone seemed to have used for this arrangement so I figured he must have been right.

 

[tumbleweed1002]

Yea you need the corrector it is attached to the linkage on the carb and the tv cable hooks to it, it is a must and i mean MUST on the 700r4.

 

[tumbleweed1002]

This is a pic of the linkage peice.

 

[lectric80]

Basically it sounds like there is too much tension on the cable, that in turn makes the tranny think you are pounding the gas so it doesn't shift until much higher RPM's. That is the way it sounds based on the new carb.

 

[mbood82]

If I go with the corrector piece I linked to it appears that there is an issue with the bracketry. Every bracket I have seen so far has the cable attach on the inside of the carb lever but that piece appears to attach to the outside of the carb. Thoughts?

Tumbleweed, I can't see the image you posted. I don't have permission.

 

[cabledawg]

It's the same thing you found at summit, just a pic of it installed on the carb.

 

[mbood82]

Sounds good. I'm ordering one this week. I did get the truck running and driving correct today but I don't plan on driving it now until I pick that up so I can be safe.

 

[mbood82]

Picture of the truck

Modification required to application specific TCI throttle cable and TV cable bracket. Kinda screwy..

The stable

 

[Blue85]

You could unclip the TV cable entirely and take a VERY short, VERY low throttle drive (just far enough to get a shift, then stop). If it lazily slides into 2nd gear at a crazy low rpm, then the tranny is fine and the problem is just with the cable linkage. If it still revs to the sky, the TV is probably stuck. This is just a one-time troubleshooting thing.

 

[mbood82]

There was something stuck in the TV line or something then I assume, when I first put the carb on it wouldn't shift out of first until a crazy high rpm even with it unhooked, never mind on and supposedly adjusted correctly.

it works great now though, so i'm happy.

 

[Drey]

will I need that tv cable adapter for a edelbrock carb?
also are the tv cables different from deisel to gas?


I had a tranny do that, Dad and I couldnt figure it out, we ened up shelling out the tranny about a week later. But it was a $300 pickup that had lasted us a year so it didnt really matter

 

[lectric80]

For pretty much any after market carb you are going to need the correct adapter for the TV. I don't think there is any difference on the diesel and gas, but I am sure someone will correct me if I am wrong.