Hot Rod Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
179 Posts
Discussion Starter #1
I have a 1983 chev 1/2 ton 4x4 305 with auto OD trans.It shifts fine with the selector in the OD position.When it is moved to the 1,2, or D positions it slips like crazy and will hardly move. Put it in the OD position and it acts normal, Reverse works fine. Anyone have a clue as to what is wrong,thanks.DOUG
 

·
Registered
Joined
·
685 Posts
Doug this problem is somewhat of an anomaly. The overrun clutch is on in manual 1st,2nd,and 3rd. It is not applied in the D4 position,or in reverse.

A pressure gauge would help in the diagnois,but the symptoms point to major problems,inside trans.
 

·
Administrator
Joined
·
9,766 Posts
DougMN said:
Anybody else?

A pressure test would be the first item to check. As brisco pointed out this problem you describe is unusual. If there is a problem with the main line PSI it can indicate a serious internal problem.

A more common complaint is the 700/4L60 tranny will not move in the "OD" position on the shifter and will move when the shifter is in "D" or 2 or 1.

What is the history on this tranny?

Any Recent repair work on it?

What is the mileage & age if there is no recent repair/rebuild?

:cool:
 

·
Registered
Joined
·
329 Posts
Transmission

Add Lucas Trans Addivtive it fixed my transmission change oil then add I thought I was going to shell out $1800.00 dollars try it won't hurt.
 

·
Registered
Joined
·
685 Posts
Or,you can take that money you were going to spend on the lucas and buy a pressure gauge.

I've been posting on this site for over two months now,when it comes to transmission issues,there is no one you would rather have answer your post than Crosley,and you've got him scratching his head. I'm no slouch either,but if you want some answers for this specific transmission concern we will need to see pressure readings. And Tony thats Briscoe with an e. :D
 

·
Registered
Joined
·
576 Posts
700

ok everyone here if you need answer's on most tranny questions for god sake buy a pressure gauge first, because thats tell us so much more. NOT
I'm not trying to be a smart *** but there are answer's you should be able to give without starting with check the pressure. most here are do it yourself guys and tools are kept to a minimum. I know you mean well and know your job but it just gets frustrating to see your answers the same way " get a pressure gauge and tell us the reading", I have had that line from so called tech guy's on the other end of the phone when I have had trouble before. I'll give you a guess to go with from years of my own mistakes and the fix maybe this. pressure gauge isn't the answer when all is with in spec's some times it old fashion seat of your pant guess work and
O J T .
I have been building a data base since 1989 on things I have found out the hard way, and all of them without a pressure gauge,700'S are a small part of what I work on and everyday brings something new.
 

·
Administrator
Joined
·
9,766 Posts
airworld2 said:
ok everyone here if you need answer's on most tranny questions for god sake buy a pressure gauge first, because thats tell us so much more. NOT
I'm not trying to be a smart *** but there are answer's you should be able to give without starting with check the pressure. most here are do it yourself guys and tools are kept to a minimum. I know you mean well and know your job but it just gets frustrating to see your answers the same way " get a pressure gauge and tell us the reading", I have had that line from so called teach guy's on the other end of the phone when I have had trouble before. I'll give you a guess to go with from years of my own mistakes and the fix maybe this. pressure gauge isn't the answer when all is with in spec's some times it old fashion seat of your pant guess work and
O J T .
I have been building a data base since 1989 on things I have found out the hard way, and all of them without a pressure gauge,700'S are a small part of what I work on and everyday brings something new.

OK....... a gauge reading is unneeded here.

i do not see any suggestions for the fellow's problem from you.

As I posted it is more common for the trans to not move in "OD" , then move forward in "D". this would indicate a problem in the forward sprag.

IF the trans did not move forward in "OD" or "D" or 2....... but it would move in "1" .... that would indicate a problem in the low/reverse roller clutch area in the center support...

Since the fellow states the trans works well in "OD" , but slips in "D" , 2 & 1 ....... where is the problem?

IT would seem a pressure problem may show up... yet on the flip side the rotor / vane pump is good at covering up a pressure loss problem in the trans. This possibly could be difficult to read without a cooler line pressure reading.

As I am sure you know IF there is a pressure loss/drop that the pump is covering up , the cooler line pressure and flow drop waaaay off.


That is also the reason I asked for a history on the tranny...


:cool:
 

·
Administrator
Joined
·
9,766 Posts
briscoe said:
Or,you can take that money you were going to spend on the lucas and buy a pressure gauge.

I've been posting on this site for over two months now,when it comes to transmission issues,there is no one you would rather have answer your post than Crosley,and you've got him scratching his head. I'm no slouch either,but if you want some answers for this specific transmission concern we will need to see pressure readings. And Tony thats Briscoe with an e. :D

yer lucky I got most of the letters in


;)
 

·
Registered
Joined
·
576 Posts
700

yea I didn't post idea but there is more to this story, I feel that someone has tried to rebuild and has placed mis match parts here. pump stator and pump face would be my first guess, this would cause a cross leak when you use over run plates. wrong stator shaft installed in stator half = holes not lined up, cross leaks.
was fluid burnt , anything after that is guessing.
 

·
Registered
Joined
·
685 Posts
Doug,can you give us a little more info to go on?

Since we are just guessing here.... If you built trans,and "mis matched" pumps,these are some of the possibilities. Your trans is an early unit,small shaft. Your pump stator[side with stator shaft] should have a 7/32 air bleed,top right,drainback hole lower left. There is no casting in either the pump body or the pump stator on the early pumps to block mainline pressure to this hole,so GM put a plug there.

No problem early to early halves. You do need to know this though They put a casting on the later halves,but left the hole open[unplugged].

You can match the later pump body to the early pump stator,because the hole is plugged,in the stator.

But Doug, if you matched your early pump body,no casting,to a later pump stator,which has an open hole,this is a problem.

The good news is you won't need a gauge. The bad news is,this would be a major mainline pressure leak. More good news,you did'nt do this.

If you did "mis match" pumps this way,the leak would be so severe you would have a problem in every range,including OD position,again no need for a gauge here.

Maybe you pressed the stator shaft from the stator half,then pressed it into another stator half,"because your half was bad". Then suppose you pressed it together,but you didn"t line up the holes. More good news,you didn't do this either. How would you have bolted it[stator shaft] to the stator half.

I'm finished guessing now,to many possibilities.
 

·
Registered
Joined
·
576 Posts
700

well this post is way off the base question, but lets continue
you can remove the old stator shaft then pin from stator face use valve body bolts to line up stator shaft press new shaft in, the replacement shaft aftermarket has elongated holes to ensure correct feed to stator face for different years inter change.
I can state with no fear I have made mistake's interchanging parts trail and error. but those who do not try cant say that wont work, I can tell you what I have found to work. good builder's go beyond what the book states fits interchange is trail and error and time behind the builders table is knowledge. guess work thats what we are here for no hands on or real test drive here ,with years of doing transmission repair I get questions over the phone all the time whats wrong with my car. most the time I have seen the problem before and can tell them what my idea is but I cant fix it over the phone.
 

·
Administrator
Joined
·
9,766 Posts
airworld2 said:
well this post is way off the base question, but lets continue
you can remove the old stator shaft then pin from stator face use valve body bolts to line up stator shaft press new shaft in, the replacement shaft aftermarket has elongated holes to ensure correct feed to stator face for different years inter change.
I can state with no fear I have made mistake's interchanging parts trail and error. but those who do not try cant say that wont work, I can tell you what I have found to work. good builder's go beyond what the book states fits interchange is trail and error and time behind the builders table is knowledge. guess work thats what we are here for no hands on or real test drive here ,with years of doing transmission repair I get questions over the phone all the time whats wrong with my car. most the time I have seen the problem before and can tell them what my idea is but I cant fix it over the phone.
hence my question on the history of the trans in this thread.... With a tranny that is 2 decades old , who knows what has been done to it.

I receive email every day with questions on trannys. Some questions i can answer , some I can not.


Some days I think there is 'voo doo' to these automatic trannys.... although I have been told there is not.


:D
 

·
Registered
Joined
·
685 Posts
When I was a young builder,mid 1980's,I put a big shaft pump in a small shaft 700....in a state police car. The trooper brought it back complaining of a vibration.

My boss asked me[told me] to go for a roadtest with the trooper,so we did.

The vibration was most noticeable at 120 mph! No lie.

Coolest roadtest I've ever been on.

Yes we all make mistakes,but if we post here to help,we need to be as informed as possible. Our mistakes,thru our suggestions,can be a real big hassle to who ever uses our advice.

You can never ask enough questions,you can never be too informed.

Sure wish Doug would post back,I think our fighting scared him away :D

And yes,after 30 years of doing transmissions,I'm convinced about the "voo doo" thing.
 

·
Registered
Joined
·
685 Posts
Unfortunately Doug there are only two simple things you can check that may create this situation,that I can think of.

First is fluid level. Second is tv cable,out of adjustment,low tv pressure rise.

Are you familiar with checking tv cable? Over time,the cable can stretch,which would cause a low tv pressure condition. This would make the trans slip.
 

·
Administrator
Joined
·
9,766 Posts
I do not see a history on this tranny in this thread.

Mileage ? , recent repair or rebuild work?

At the carb where the TV cable is hooked...... someone needs to sit in the vehicle ( engine OFF) push the gas pedal to the floor.

Pull on the TV cable while the trottle is held to the floor . Then check for full pull at WOT ( Wide Open Throttle). Check for a loose cable at WOT.

Is the cable hooked up?

If you can not preform this procedure , find a knowledgeable tranny shop or person to help....... good luck.

post back if you need more help.


:cool:
 
1 - 20 of 20 Posts
Top