95 Explorer OD Light blinking

[CecilB]

My 1995 4.0 V6, 4X4, 110K. The OD switch just started blinking on the dash without any warning. The engine and transmission was running fine. The lite just came on, and I noticed the RPM is running high when shifting into 2nd gear. If I accelerate and then take my foot off the gas, it's shifts easily into 2nd gear. All the other gears are fine. This hard shifting into 2nd gear, just started after the OD switch started blinking on the dash without warning. I bought an OBD1 code reader and found the following codes:
Engine OFF, Ignition ON: Code 646 - Incorrect Gear Ratio obtained for 2nd Gear - Second Gear failure.
Engine Running : Code 632 - O/D Cancel switch, Overdrive cancel switch did not change state during KOER.

I disconnect the battery for 2 minutes and then reconnect it and the OD blinking light went out. I drove the car and it shifted fine in all the gears even 2nd, however, about 30 minutes into the driving I went up a steep hill and turned to go down another hill and the OD started blinking ( about 25-30 MPH). I disconnected the battery again and manually turn off the OD using the OD/switch on the Gear shift and the transmisson shifted fine. I drove it and after about 30 minutes the OD light came back on. I don’t hear any strange noise or metallic sound from the transmission. I changed the transmission fluid and filter last summer, less than a year ago and installed Dextron III Synthetic. The fuel level is fine.
What do I need to do to correct these two codes listed above? I’m planning on dropping the transmission pan this weekend and check out the valve body to insure everything is snug and good. Any help appreciated. Thanks in advance for your assistance.

 

[bronx explorer]

first welcome to the site i just got a 95 explorer and started to do the same thing and what i did was flushed the tranny and replaced the filter then i put a bottle of luccas for the tranny and the truck runs even better the rpms droped and picks up verry good. if that dont work you can look up on the site and they will be a lot of the same things and deferant thing they did to fix it so good luck and visit more. i hope this work as it did for me.

 

[CecilB]

first welcome to the site i just got a 95 explorer and started to do the same thing and what i did was flushed the tranny and replaced the filter then i put a bottle of luccas for the tranny and the truck runs even better the rpms droped and picks up verry good. if that dont work you can look up on the site and they will be a lot of the same things and deferant thing they did to fix it so good luck and visit more. i hope this work as it did for me.

Thanks for the response. I'll be changing the fluid and filter tomorrow and will try and find a bottle of LUCCAS for the tranny to add. I'm thinking of checking out the valve body while I'm in there and cleaning it, but don't know how much work is involved and if any special tools are required. I'll start with the flushing and see what happens. Thanks again.

 

[CecilB]

Thanks for the response. I'll be changing the fluid and filter tomorrow and will try and find a bottle of LUCCAS for the tranny to add. I'm thinking of checking out the valve body while I'm in there and cleaning it, but don't know how much work is involved and if any special tools are required. I'll start with the flushing and see what happens. Thanks again.

I changed the filter, added synthetic fluid and LUCAS additive and it's didn't work. NO metal found in the fluid/pan and it did not smell burnt. It was pretty clean. The OD light still blinking and still getting CODE 646 - Incorrect Gear Ratio obtained for 2nd Gear - 2nd Gear Failure and the transmission is REVVING High before shifting into 2nd gear. Do I have a 2nd gear solenoid that shifts the gear? I noticed on the VALVE BODY they are 4 solenoids on driver side and 2 solenoids on the passenger side. Can someone identify which is the 2nd gear solenoid and if there is an easy way to test it. I'm thinking of changing it and see if it corrects the problem. it? Any help appreciated.

 

[RickOTR]

Make sure all the solenoids bolts are tight against the valve body first. The ECU which is located on the drivers side at the back of the valve body is what controls the forward and rear engagement of the tranny.RangerBill at http://groups.msn.com/RangerBill/transgo.msnw has a good view of the valve body solenoids and installing the TransGo shift kit. The seafoam trans tune is another good product. Just put it in and let it idle for about 30 minutes, then flush the tranny. Really made a difference in how the X shifted. Hope this helps.

 

[CecilB]

Thanks RickOTR for the advise. I'll look in the TansGo shift and see how it goes. I'm still intrested in know if anyone had the error code 646 and what they did to fix it. Thanks again.

 

[killswitchfan134]

i'm getting the error codes 646, 647, 648 so im thinking that im done for i might have to get a new trans unless me and my friend can figure out whats going on

 

[pj8847]

I'm beyond shocked that nobody mentioned making sure the VB gasket is intact and didn't blow out somewhere...

Usually it is the main cause of many transmission problems in these trucks...

From shift flares to no engagment at all, the VB gasket, as simple as it sounds, may be the problem.

 

[sajaylu]

I am having the same problem but I have not pulled the codes from my transmission. It look to me that the people that are having this problem it steams from the Valve Body. A lot of people have the valve body gasket and how it goes all over the transmission. I plan on flushing my transmission cause just changing the pan oil will not get whats in the torque converter, changing the valve body and adding a second transmission filter with a Magnet. I won't give it a reason to mess up again.


Here ya go for the Valve Body:
http://800700tran.com/level.itml/icOid/152

Magnets that keep there strength ever at 500F: That would go on the external filter that's away from other electrical equipment:
http://www.magnet4sale.com/SmCo-Magnets-2-X1-2-X1-2-.-572F-Operating-Temperature.html

Here is the filter for the transmission:
http://www.puredieselpower.com/catalog/external-remote-transmission-filter-kit-p-943.html



The extra filter and the magnets are over kill as long as the internal filter is changed on schedule things will be fine.

 

[Bajadaze]

Okay, Here's what I've got. 95 Ford Explorer, O/D light flashing. Did a jump test and read the blinks of the check engine light. Did it with someone that knew how it's done. It was a KOEO test. The results were: 47 62 64 76. I'm looking everywhere for these parts for a fix.
Is there anyone on the up about where I might go from here? I know enough to get in trouble.. Perhaps a URL with a description of what needs to be done and in the proper sequence. Much appreciated in advance... Bajadaze, where the car is and will remain til death us do part.