Okay I have done a lot of searching and the only thread I found that may help me is this one: http://www.pirate4x4.com/forum/showthread.php?t=259701&highlight=700r4+shift

Near the end, orangefj45 starts on a train of thought that I think would help me, but he never gets back into the discussion. Here is what my 700R4 is doing:

The 700R4 in my 1990 Burb won't shift into OD when I give it any gas at all. If I let off the gas while going down the road it will shift into OD, but the moment I give it any amount of gas it goes right back into 3rd. The TV is adjusted correctly. I have checked the pressure and at idle in P, N, OD, and 3rd I get 75 psi; in 1st and 2nd I get 180 psi; in R I get 130 psi. When I move the TV any amount by hand with it hooked up to the TB the pressure starts to rise immediately.

This is a GM remanufactured tranny that was installed about two years ago. I purchased the truck about a year ago. The previous owners also added 31" tires, which are larger than stock. It still has the stock 3.73 gears. I added a TB spacer and have been running that for a year. I was in the past few weeks that it wouldn't shift into fourth unless I was coasting. All other gears shift at the appropriate time and with the appropriate feel. I can sense no slipping.

I forgot to add that before it wouldn't upshift into OD at all I could force it to by driving between 75 and 80 mph, letting off the gas, coasting for a moment, and then feathering the gas on. It did this for a couple days before it started doing what is mentioned above.

If you can offer any help I would appreciate it.

Kevin

After reading that thread it seems that it wasn't the fact that orangefj45 did not get back in the disscusion.. He was waiting for the original poster to provide some more info which he did not so there was no way that he could provide a sollution with out more input.. Just my 2 cents..

My 1st thought was your TV cable was not adjusted properly but after reading your post it sounds like your confident that you checked it out pretty good.. I dont want to give you any misinformation.. So here is what I suggest send a PM to orangefj45 because he knows alot about transmissions and probably will have some good imput.. I'm sure somebody will reply with more info.. Good luck

lock up and od are computer controlled and look at tv pressure, vss and tps reading to determine operation by changing tire size and not correcting vss the computer doesn't see proper input to control lock up and od correctly I have seen some trucks that never have a problem and others that do my s10 blazer is a real pain in the ass to keep in od at times I have never found any correction either maybe someone out there has

Thanks for the input, guys. I sent orangefj45 a PM.

bronco75: OD, AFAIK, is not computer controlled on my 700r4. I have spent a lot of time studying the FSM and the only electrical connections are for TC lockup.

Kevin

Overdrive is NOT electronically controlled. The only thing that is the TCC solenoid, but it will not cause a no overdrive condition..

First thing, loosen your TV cable two clicks and drive it, be easy on it and see if it goes in. Don't drive it long at the reduced pressure. If 2nd works and third works, then overdrive should.

Then, if you do get overdrive, readjust the cable per specs, which is, have someone hold the throttle to the floor from inside while you push the cable back into the housing till it stops. That is the best way to adjust it.

Second thing I would look at is the governor, check to make sure the top is not loose, that the valve inside it moves freely.

Start there.

sounds like lumpdog has your next steps all layed out for you/

a couple more questions:
how many miles are on it?
when was the last time the trans was serviced?
did you service it yourself?
does it slip when it shifts into OD?

There are about 20,000 miles on it. I have not yet had it serviced. I was going to drop the pan tomorrow, change the filter and refill it. I detected no slipping when it did shift into OD...I can't tell if it does right now because it only shifts into OD when I am coasting.

I will also do what lumpdog suggested and let you all know how it goes.

Kevin

Check your engine timeing and vacuum advance. Make sure your getting the proper vacuum.

Check your brake switch as well. Tapping the brakes will disengage it. If your brake switch is malfunctioning...

th700s do not rely on vacuum for input.

tapping the brake switch will cause the converter to come out of luck-up in 3rd and 4th, but has nothing to do with OD itself.

The 700 only requires two inputs to shift all the gears

1. road speed via the governor
2. throttle percentages via the tv cable...

Have you noticed a change in all the shifts in the trans??

th700s do not rely on vacuum for input.

Maybe I should elaborate a little more. The first two things to check when you suspect a tranny problem is tranny fluid level, and engine timing. Even the Haynes manual lists it in that order. If the engine isn't timed correctly, the tv cable will not control fluid flow properly. To me it sounded like his tv cable/tranny is reacting to 3/4-full trottle. Like he is trying to pass and downshifts into 3rd gear, or in this case never shifts out of 3rd gear. Once he lets off the trottle and coasts, all is right in the world and it shifts into 4th gear, OD, just like it does when you pass and back off the throttle. A vacuum problem would be the easiest to miss, and the ECM will adjust timing, but only so far. The higher the rpms the more timing and vacuum becomes a problem. Thus my susgestion to check engine timing and for vacuum leaks. Sure it could be a governor, or a sticking valve, or a host of other things causing his problem. However, I like to rule out the simple stuff first.

Maybe I should elaborate a little more. The first two things to check when you suspect a tranny problem is tranny fluid level, and engine timing. Even the Haynes manual lists it in that order. If the engine isn't timed correctly, the tv cable will not control fluid flow properly.


Whatever then, you can stick to the "haynes manual" :shaking: on your junk and leave technical stuff to the factory trained and mucho experienced trans gurus (as Orange has branded me!).

The TV cable is purely mechanical, timing will not affect it, and the computer does ZERO for control of the shifting, only the TCC operation.....

It is assumed that your engine runs ok, if it is a total piece of crap that won't move itself outta the driveway, then that would affect the shifts.....

But like I said earlier, shifts are by road speed and throttle angle, not rpm's!!!!

If the engine isn't timed correctly, the tv cable will not control fluid flow properly.


:laughing:

i love it when shade tree mechanics chime in with their good intentions and they don't know what the heck they're talking about! :flipoff2:

Only my input. Wrong, maybe?
Ass-u-me all you want. And your positive its 4th gear hes talking about and not TCC lock-up? :D

Shade tree, yep, but not my first rodeo. :flipoff2:


Since your the expert, I'll bow out and let you take care of it them. :laughing:

Can't we all just get along? :)

I have said before that it is OD that is the problem and not the TCC. I dropped the pan yesterday, replaced the filter and then had the tranny flushed. There were no signs of any abnormal wear and no debris in the pan or fluid. The fluid was not burned, either. I took it for a spin afterward and it still exhibits the same problem. Tomorrow I will pull out the gov and see what it looks like.

Is it possible that when the previous owner went to 31" tires from the stock p235/75R15's that this messed up the shift points? It seem to me it would as the 31s are larger and this would make the trans think the truck is going slower than it actually is. I really appreciate all the help and input. I will keep you up-to-date.

Kevin

For the record, with 31's & 3.73's you shouldn't even be TRYING to use OD unless you're running 70+ WITHOUT a load & WITHOUT any significant hills.


TEX

absolutely correct. the larger tires will definetly throw a wrench in the equation.

Since your the expert, I'll bow out and let you take care of it them. :laughing:


i'm no expert, i just BS with the best of em! :grinpimp:

lumpdog is the man when it comes to transmission tech since he's been building them for quite a while. i used to be a service writer at a trans shop for 7 years and have been in the transmission parts business for almost 5, so some of this stuff has finally rubbed off on me.

For the record, with 31's & 3.73's you shouldn't even be TRYING to use OD unless you're running 70+ WITHOUT a load & WITHOUT any significant hills.


TEX



Hmmm, my overdrive worked great with 3.73s and 35's in a 7000 lb truck with a wore out carbed no mods 350 for 4 years........Yes, tire size will change shift feel etc. but it will still be the same rpm shifts... If your engine has no nuts, then it will feel like it is hunting for overdrive, but he says that his kicks out completely, not surging in and out or "hunting".

I guess driveshaft speed would be better to say than road speed.....

Plus, 31's are not that big of a jump from 235's. There are quite a few trucks I have built tran's for with 33's and 3.42.......

Hmmm, my overdrive worked great with 3.73s and 35's in a 7000 lb truck with a wore out carbed no mods 350 for 4 years........

You sure it EVER actually shifted into OD? You'd be so ridiculously below your engine's optimum operating RPM with 35's, 3.73's, & .69:1 top gear that you probably would have gotten better fuel mileage in 3rd. Heat is what kills TH700's & trying to run OD under less than optimum conditions is what most often builds that heat.

TEX

i'm pretty sure lumpdog knows what gear his trans is in. :laughing:

i'm pretty sure lumpdog knows what gear his trans is in. :laughing:

Does he enjoy the sound his engine makes at 1,500 RPM on the highway? :p


TEX

Oaky, I just pulled the gov out.

First, the sleeve is quite loose on the body. Is this normal?

Next, there are two different color springs: one green spring (light) and one light blue spring (heavy).

The gear is green and is in great shape.

The valve operates smoothly in the sleeve except that the sleeve is loose on the body and gets a bit crooked. When the sleeve does get crooked the vavle doesn't operate smoothly.

The FSM states that the entry and exhaust openings should be .020. Both are larger on my gov.

You sure it EVER actually shifted into OD? You'd be so ridiculously below your engine's optimum operating RPM with 35's, 3.73's, & .69:1 top gear that you probably would have gotten better fuel mileage in 3rd. Heat is what kills TH700's & trying to run OD under less than optimum conditions is what most often builds that heat.

TEX

Never had heating issues, I have all the crap parts in it, and she's still going strong after 4 years.....never have had a problem......and to top it off, for 2 1/2 years I was using it to commute 50 miles one way to work on the interstate.....I know what gear gave me the best mileage!

The head of the governor should not be loose on the shaft....It is common to see the head get a little loose and then not allow or change the shifts. If you look inside the gov you will see where the head is swaged onto the shaft, if there is any movement at all, replace it.....

The springs are supposed to be different, otherwise it wouldn't shift or at extremely high or extremely low points.

Lumpdog,

That's what I figured. Thanks for the input. I really appreciate it.

Okay...I got the new gov and it has a red/orange spring (light) and a pink spring (heavy). Should I swap the springs from my original gov into the new one or will I be okay using the new one as is? Thanks for the help, everyone. This has been a very educational experience.

Kevin

Ttt

Go ahead and slap her in as long as you got one for your application. If your shift points are not perfectly tailored to your liking, get one of the superior governor weight and spring kits, and respring/reweight your governor as needed. It takes a little more time, but well worth the finished product in the end!

You guys have been great! I put in the new gov and the truck works great again. I can't thank you all enough! This has been a good learning experience for me. Automatic trans had always been my weak area.

Kevin

hmmmm, so the timing or the vacuum didn't fix it and you didn't have to drop tire sizes???, imagine that!!!! :D :D :D


Sorry, couldn't resist, no offense hanr or tex.....lol I just have alot of experience on 700's.....

Glad to be of some help and that it was that easy to fix!

hmmmm, so the timing or the vacuum didn't fix it and you didn't have to drop tire sizes???, imagine that!!!! :D :D :D




:laughing:

right-on lump doggie! once again you were right on the money.

i tell people all the time that automatics are "a whole nother science" and it takes a trained professional to diagnose them properly. on the other hand, i never discourage mechanically inclined felolow wheelers from attempting to repair or rebuild them themselves, as long as they have the proper tools, instructions and ability.

hmmmm, so the timing or the vacuum didn't fix it and you didn't have to drop tire sizes???, imagine that!!!! :D :D :D


Sorry, couldn't resist, no offense hanr or tex.....lol I just have alot of experience on 700's.....

Glad to be of some help and that it was that easy to fix!

Great job Lumpdog. You nailed it!!!
I have only rebuilt mine, and then rebuilt it again with the help of a pro. I learned alot in the 3 hours I spent helping him, but not everything. :grinpimp:

I have got hundred's of hours in rebuilding 700's........if you are unlucky enough to have to build as many as I do, then ya get pretty good at them.

I am all about having guys that have a little ability tear down and fix their own trans and I try to help them as much as possible. Usually what happens though is they get the first one done, then they say fawk it and pay me to rebuild the rest!!

Sorry, couldn't resist, no offense hanr or tex.....lol I just have alot of experience on 700's.....



For the record, I knew there was an actual problem with his tranny - just chiming in with MY experience with TH700's & that's that you don't even WANT to use OD unless speed & load (lack thereof) dictate ;)


TEX

For the record, I knew there was an actual problem with his tranny - just chiming in with MY experience with TH700's & that's that you don't even WANT to use OD unless speed & load (lack thereof) dictate ;)


TEX

and that's what's great about this board. people willing to share info. :D

I have got hundred's of hours in rebuilding 700's........if you are unlucky enough to have to build as many as I do, then ya get pretty good at them.

I am all about having guys that have a little ability tear down and fix their own trans and I try to help them as much as possible. Usually what happens though is they get the first one done, then they say fawk it and pay me to rebuild the rest!!


I don't mind doing it. In fact when I rebuilt the one in my '93 I will do most of the work and take it to the pro to verify and make the upgrades. Unless you think you can walk me through the upgrades over the net. :D
I am not impressed with the repair manual I bought, seemed to be missing some steps and some key info, like gap settings in the 3/4 clutch pack. Got any recommended manuals for the 700/4L60(e)?

If you stick to a .003 to .004 per clutch on setup, then it will work great. I think the factory spec is .025 to .050, not sure, never use it. I always set up the 3-4 clutch between .015 and .025.

The ATSG is about the best manual that I have used, and get the update book too. If yours is a 93, then it should have been a 4l60e, not a 700, although most of the hard parts interchange.

I doesn't take much to rebuild an automatic except attention to detail, patience, and cleanliness..... :D

If you stick to a .003 to .004 per clutch on setup, then it will work great. I think the factory spec is .025 to .050, not sure, never use it. I always set up the 3-4 clutch between .015 and .025.

The ATSG is about the best manual that I have used, and get the update book too. If yours is a 93, then it should have been a 4l60e, not a 700, although most of the hard parts interchange.

I doesn't take much to rebuild an automatic except attention to detail, patience, and cleanliness..... :D

The one I rebuilt was a 700R4 out of my '87 S10-Blazer, then next one will be out of the '93 S10-Blazer. Thanks for the info.

i sell the atsg manuals at work. the one for the 4L60E is different than the one for the th700 because of all the added electrical components.