Welcome to AutoForumz.com!
FAQFAQ    SearchSearch      ProfileProfile    Private MessagesPrivate Messages   Log inLog in

doug nash 4+3 help please

 
   car problems (Home) -> GM -> Corvette RSS
Next:  Japan vs USA Camry  
Author Message
wolfgang

External


Since: Jun 21, 2005
Posts: 2



(Msg. 1) Posted: Tue Jun 21, 2005 1:16 pm
Post subject: doug nash 4+3 help please
Archived from groups: alt>autos>corvette (more info?)

Hi all, have an 87 convertible with the manual 4+3. When I press the button
to activate the OverDrive, the light comes on the dash but it doesn't
engage. The RPM's stay where there at. Also, while slowing down in second
gear the tranny pops out of gear occassionaly?? I seriously doubt the
previous owners ever changed the transmission fluid.. the car has 41k miles
on it... any thoughts as to what might be the issue and how to correct?
Any help would be greatly appreciated.

thanks
wolf.

 >> Stay informed about: doug nash 4+3 help please 
Back to top
Login to vote
private

External


Since: Mar 09, 2005
Posts: 8



(Msg. 2) Posted: Tue Jun 21, 2005 10:55 pm
Post subject: Re: doug nash 4+3 help please [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

"wolfgang" wrote in message

 > Hi all, have an 87 convertible with the manual 4+3. When I press the
button
 > to activate the OverDrive, the light comes on the dash but it doesn't
 > engage. The RPM's stay where there at. Also, while slowing down in
second
 > gear the tranny pops out of gear occassionaly?? I seriously doubt the
 > previous owners ever changed the transmission fluid.. the car has 41k
miles
 > on it... any thoughts as to what might be the issue and how to correct?
 > Any help would be greatly appreciated.

Check the wire connector on the side of the OD. If the connector is tight I
would check the wire for voltage with a multimeter in various switch
positions. You could run a wire under the door to check operation when in
motion or test on a hoist(CAREFULLY). If the wire is functioning correctly
you will need to test the solonoid but I do not know how to do this. Good
time to find a real GM manual, ask at a Vette dealer.

If you mean that the 4sp trans is popping out of gear, this is not a good
sign. I would suspect (aggressive shifting caused) worn thrust washers in
the tranny or damaged shift rings but would want to check the adjustment of
the shift linkage first.

I would also want to change the oil in the trans (save the oil in a clean
container and search for metal both with a magnet and visually after
straining with a coffee filter. Do the same change for the Dexron fluid in
the OD. If the trans seems overfilled suspect the input driveshaft seal of
the OD leaking into the main trans. This happened to mine at 70,000 miles.

My current (1987 Z51) OD problem is with too easy kickdown. The OD kicks
down under part throttle when I want it to stay in high gear. I am
considering rewiring the OD switch to operate full manual with no auto
kickdown. I also suspect it may be an adjustment issue with the throttle
position sensor. If anyone has done the switch rewire to full manual or
throttle sensor adjustment I would appreciate guidance.

It has been suggested that the best fix is a new Richmond 6 speed trans as
the OD is expensive to repair. In my case the reseal job was not expensive
and it was good that I removed the tranny because the clutch was down to the
rivets but was not slipping.

Happy trails to all.

 >> Stay informed about: doug nash 4+3 help please 
Back to top
Login to vote
larrybud2002

External


Since: Dec 10, 2004
Posts: 19



(Msg. 3) Posted: Wed Jun 22, 2005 3:53 pm
Post subject: Re: doug nash 4+3 help please [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

wolfgang wrote:
 > Hi all, have an 87 convertible with the manual 4+3. When I press the button
 > to activate the OverDrive, the light comes on the dash but it doesn't
 > engage. The RPM's stay where there at. Also, while slowing down in second
 > gear the tranny pops out of gear occassionaly?? I seriously doubt the
 > previous owners ever changed the transmission fluid.. the car has 41k miles
 > on it... any thoughts as to what might be the issue and how to correct?
 > Any help would be greatly appreciated.

I would think the tranny pop could be solved with a rod adjustment.

As far as the OD, change the oil AND FILTER right now, and do it every
year. Couple be a couple of things with the OD. Here's how it works:

When you press the button, it's a momentary switch that sends a signal
to the ECM telling it to toggle the current state of the OD. The ECM
determines if it should be on or off, and sends that signal to the
overdrive relay. When the relay energizes, it energizes, the light
comes on the dash, and it energizes a solenoid in the valve body of the
transmission. A valve body is just hydraulic "switches" that open
and close to route the transmission oil to the proper path to put it in
the gear required.

Since the light is coming on, we know the switch, ECM, and relay is
working. The question is: Is the signal getting to the solenoid. If
yes, is the solenoid switching? If no, then there could be debris in
the solenoid that is preventing it from moving. The solenoid is just a
piston in a cylinder (it's only about 1/2" in diameter, if I remember
right), that is spring loaded.
 >> Stay informed about: doug nash 4+3 help please 
Back to top
Login to vote
larrybud2002

External


Since: Dec 10, 2004
Posts: 19



(Msg. 4) Posted: Wed Jun 22, 2005 3:58 pm
Post subject: Re: doug nash 4+3 help please [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

 > My current (1987 Z51) OD problem is with too easy kickdown. The OD kicks
 > down under part throttle when I want it to stay in high gear. I am
 > considering rewiring the OD switch to operate full manual with no auto
 > kickdown. I also suspect it may be an adjustment issue with the throttle
 > position sensor. If anyone has done the switch rewire to full manual or
 > throttle sensor adjustment I would appreciate guidance.

The TPS MUST be in the proper position and working correctly for kick
down to occur right. You should test the TPS at idle. It should be
exactly 0.54 volts. Are you having idling problems? I have a scan
tool which tells me the TPS voltage, but if you look in your Helm
manual (you have one, right?) it will tell you which wires to probe.

I REALLY recommend NOT rewiring the OD. I did, and I suspect it's one
of the reasons for early failure. The OD is not designed to be run in
first gear, and rewiring it would let you do that. If you insist,
you're going to replace the OD switch with a manual toggle on/off (it's
a momentary switch right now), then you would route the signal from the
switch from the ECM to the relay. IOW, the switch right now goes into
the ECM. You would bypass the ECM altogether.


 > It has been suggested that the best fix is a new Richmond 6 speed trans as
 > the OD is expensive to repair. In my case the reseal job was not expensive
 > and it was good that I removed the tranny because the clutch was down to the
 > rivets but was not slipping.

I put the Richmond in mine in August 03. I love it, but this year 6th
gear broke. Sent the tranny back to Richmond and they fixed it for
free, although it did cost $135 to ship the thing.

<a rel="nofollow" style='text-decoration: none;' href="http://www.areddy.net/vettetrans" target="_blank">http://www.areddy.net/vettetrans</a>
 >> Stay informed about: doug nash 4+3 help please 
Back to top
Login to vote
wolfgang

External


Since: Jun 21, 2005
Posts: 2



(Msg. 5) Posted: Wed Jun 22, 2005 5:38 pm
Post subject: Re: doug nash 4+3 help please [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

thanks private.. I'll check the wire and connector.. just bought a tranny
kit for the OD..

"private" wrote in message

 >


  > > Hi all, have an 87 convertible with the manual 4+3. When I press the
 > button
  > > to activate the OverDrive, the light comes on the dash but it doesn't
  > > engage. The RPM's stay where there at. Also, while slowing down in
 > second
  > > gear the tranny pops out of gear occassionaly?? I seriously doubt the
  > > previous owners ever changed the transmission fluid.. the car has 41k
 > miles
  > > on it... any thoughts as to what might be the issue and how to correct?
  > > Any help would be greatly appreciated.
 >
 > Check the wire connector on the side of the OD. If the connector is tight
I
 > would check the wire for voltage with a multimeter in various switch
 > positions. You could run a wire under the door to check operation when in
 > motion or test on a hoist(CAREFULLY). If the wire is functioning
correctly
 > you will need to test the solonoid but I do not know how to do this. Good
 > time to find a real GM manual, ask at a Vette dealer.
 >
 > If you mean that the 4sp trans is popping out of gear, this is not a good
 > sign. I would suspect (aggressive shifting caused) worn thrust washers in
 > the tranny or damaged shift rings but would want to check the adjustment
of
 > the shift linkage first.
 >
 > I would also want to change the oil in the trans (save the oil in a clean
 > container and search for metal both with a magnet and visually after
 > straining with a coffee filter. Do the same change for the Dexron fluid
in
 > the OD. If the trans seems overfilled suspect the input driveshaft seal
of
 > the OD leaking into the main trans. This happened to mine at 70,000
miles.
 >
 > My current (1987 Z51) OD problem is with too easy kickdown. The OD kicks
 > down under part throttle when I want it to stay in high gear. I am
 > considering rewiring the OD switch to operate full manual with no auto
 > kickdown. I also suspect it may be an adjustment issue with the throttle
 > position sensor. If anyone has done the switch rewire to full manual or
 > throttle sensor adjustment I would appreciate guidance.
 >
 > It has been suggested that the best fix is a new Richmond 6 speed trans as
 > the OD is expensive to repair. In my case the reseal job was not
expensive
 > and it was good that I removed the tranny because the clutch was down to
the
 > rivets but was not slipping.
 >
 > Happy trails to all.
 >
 >
 >
 >> Stay informed about: doug nash 4+3 help please 
Back to top
Login to vote
Display posts from previous:   
Related Topics:
finding out how rare my vette is... - Hi all... Doing some research on the net, I discovered that my corvette (1992, LT1, six speed coupe) was some-what rare. Not like a buffalo nickle rare or anything, but I saw that there was less that 5,500 6-speed coupes made in 1992... I mean, thats..

Corvette shop Crestview Florida area: - I moved to Florida from virginia and have been looking for a Corvette shop in this area. Does anyone know of any mechanical and paint shops in this area. Even Pensacola area ( its 50 miles from me )? Thanks.

Traction Control - I was told about it and the dealer even had me demo it and it worked fine there, but not now...maybe. I was told that with traction control ON, the wheels would not spin and the back end would not hop. Well, it does both and I'm lucky there wasn't a cop...

65 Temp Gage Maxs Out when Ign On - My 1965 L79 Corvette temperature gage will occasionally move quickly all the way to the right (max) when energizing the ignition circuit before a cold start. After the engine starts, it stays at max for a few miles and slowly moves back left to normal. ...

fat americans use more gas - ATLANTA - Heavy suitcases aren't the only things weighing down airplanes and requiring them to burn more fuel, pushing up the cost of flights. A new government study reveals that airlines increasingly have to worry more about the weight of their..
   car problems (Home) -> GM -> Corvette All times are: Pacific Time (US & Canada)
Page 1 of 1

 
You can post new topics in this forum
You can reply to topics in this forum
You can edit your posts in this forum
You can delete your posts in this forum
You can vote in polls in this forum



[ Contact us | Terms of Service/Privacy Policy ]