700r4 binds in low

I have a question. I rebuilt my 700r4 last year and finally installed it this weekend. I seem to have a problem. In low it binds like you have the brakes on. if you give it some throttle, it will to turn the tires (on jack stands), but as soon as you let off the gas the tires stop like the brakes are on. I tried to run it through the gears in OD, the tires turn, but you can't feel it shift. It doesn't bind in any other gear, fwd or rev. Any ideas before I pull the trans?


Thanks in advance,

Stan

 

Sounds as if two of the internal members (bands, clutches) are being applied simultaneously in first. I would pull the valve body and examine the valves, balls, O-rings, etc. to see if they are in the proper places, and if any are missing.

 

I agree, I'm hoping somebody can give me an idea of which ones so when I take it apart I know what to look for. Anyone?

Thanks,
Stan

 

BBT for Monday's crowd. anybody have any help? trying to figure out what might be binding up!

Thanks,

Stan

 

I'm just gonna throw this out here...

I'm going to assume that you probably didn't completely disassemble your valve body and put all the parts in a big pan at one time before you reassembled it. In fact, I'd guess that you may not have disassembled it at all. That being said, I do not suspect a valve body malfunction to be the cause here.

I suspect your rotating assembly/clutch pack arrangement is incorrect. Either you got too many clutches/steels in one pack and it's bound up without any pressure applied or you made some other mistake in the hardware stackup.

I hate a 700R4/4L60 with every ounce of my soul. I would not wish one on my worst enemy. I think the engineers at GM that concocted this pos should be sued and imprisoned for crimes against humanity for forcing it on the general public.

Anyway, if you were closer I would be glad to try and help you get it sorted out. Unfortunately, this sort of troubleshooting is very difficult in this medium. I'd say the first step is going to be to remove it and tear it down. Something is definitely very wrong with it.

 

I did indeed tear the valve body completely down, I layed all the valves and springs on a towel in order and cleaned and reassembled one at a time. I used to rebuild transmissions for a living 18 years ago. I'm not totally a newby. I probably averaged 2 700's per week for the 5 years I worked there. I never had an issue like this. I believe I have the sprag the correct direction, the clutch pack clearances correct, correct valve body gaskets, etc... I am trying to figure out what "other components" would be engaged to cause this. The more I think about it, I'm leaning to a hung valve.

Anyone else?

Thanks,
Stan

 

Did you try it in reverse at all also to see if it does it then? To me it seems that maybe the tolerances in the low/reverse clutchpack in the bottom might be a little tight. The other possibility that I could think of is what happened to me this spring, same symtoms that you are describing only also happened in reverse. The little cogs that hold the snap ring in for the low/reverse clutch pack broke, causing it to have a ton of pressure and move like the brake was being held on. Not sure if it was any help but that's my 2 cents

 

Yea, I tried reverse. It is fine. Also no tie up in manual 2nd???

 

Something to check, I remember there was an issue with early 700s that would crack in the area where the Teflon sealing rings are. This would cause pressure to go two different directions at the same time and you could get two clutch packs partially applied at the same time.


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Yea, I know where you are talking about (where input shaft is pressed into the input drum). I air checked the drum upon assembly, but I will check that out when I disassemble! anybody else?

 

What happens in manual Lo (1st only)? Might point in the right direction to look at.

 

That is my original problem, it binds in manual low.

 

Dumb question - is the shift linkage 'proper'? Perhaps the shift selector valve isn't getting positioned correctly.

 

Good question, I will disconnect the shifter and try shifting at the transmission tonight. I have a Lokar shifter so it is possible.

 

I'm sure you already thought of this, but, check carefully for warpage or raised edges at the valve body/case mating surface.

 

I,m sure I ran a bastard file across the case when I built it 2 years ago, but if I have to pull it I will definitely check it out.

Thanks,
Stan

 

Well I found it. Several of the valves in the valve body were rusted in place. The only thing I can think of is I didn't get the case completely blown dry 2 years ago when I rebuilt it. When I rebuilt trannys for a living they went back in the car the same day so a drop or two of water wasn't an issue. Thanks all who replied. I will update the thread once I get it back together and confirm its fixed!
Thanks,
Stan


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Well I'll be damned.

I've built many engines and cataloged them away for use at a later date, but I don't believe I have ever built a transmission and socked it away. If that were ever the case I'm sure I too would've had this problem by now. Glad you got it fixed without having to tear it all the way apart.

 

thanks for the feedback, glad it was simple to fix.

Perhaps it may be wise to coat the valves with transmission fluid to keep the chances of rusting in place down to a minimum, or you can use WD-40, as this is suppose to pull water out.

 

Ok guys, now I need to figure out a way to free the rusted valves. I tried tapping them out, but they are stuck pretty good. Muritic acid? glass bead? Heat? any ideas?

Thanks,
Stan

 

try soaking it in trans fluid and acetone. supposed to be great on rust removal.

 

If you have a tranny shop near by then I would see if they have a core valve body and start over if you need it quickly. If you can wait then soak it with some good penetraiting oil,and be gentle.

 

I've used PB Blaster, soaked for 3 hours, then hit it with a heat gun.

My heat gun is a Top Flite Monokote gun for model airplane covering...much hotter than a hair dryer.

Again, thanks for reporting on the findings!

 

I'm no trans guy, but I vote for the heat gun, or even an oven. You can't even think about building a Quickchange without heating the case.

HEAT IS MAGIC!!!!

At first I thought maybe it was because you used a 'Bastard' file, the legitimate ones seem to be more socially acceptable.

 

Haven't used it yet, but METAL RESCUE is suppose to dissolve rust in 5 minutes. If you have a Menards nearby then check it out.

 

Yea, I have a Menards nearby. Doesn't everybody?, I will give it a try.

Thanks,
Stan

 

We just got our Menards about a year ago! Kantsas is slow getting new stores.

 

Well, here is the long awaited answer, I found a replacement valve body at the shop I used to work at. After I swapped the shift kit over and installed, It still bound in low and 2nd. if you continued to accelerate (all of this done on a lift) it would free up and shift 3rd then 4th.

I then proceeded to pull the trans and this is what I found, Notice the effed up Teflon ring between the Forward and 3-4 clutch feeds!

I also had to replace the slightly burned 3-4 clutches. All is well Now!

Thanks for the replies!
Stan

 

Glad you found the issue. Thanks for the update.

 

Any cross-circuit leak can be a nightmare, but those soft sealing rings are an accident waiting to happen IMO. Sure miss the old interlocking iron rings. Thanks for the update & reminder of what can go wrong here.
Doug