P0734, shifting problems with transmission 99, going on two weeks :/ 2WD Sport

[thatoneguy]

Well the situation is hard to describe since I've never had a problem like this before. I've been having transmission problems when it comes to shifting and it's got worse.

The error code I'm reading is P0734 (Gear 4 Incorrect Ratio)

About two weeks ago I started having transmission problems, shifting. If I accelerated quickly, was going up a hill or down a hill, my Explorer fails to shift around 35-40 MPH. It over-revs and then I have to let off the accelerator let it drop down to about 2/2500 RPM's and then ease on the accelerator and then it finally shifts (sometimes). Lately I've had to drop it into 2nd and then shift it into drive, I've only had to do that a few times.

I was leaking ATF and had to replace my gasket and filter so I figured maybe this is why. Did all that changed the ATF and the filter. I do noticed if I'm parked downhill/at an angle I have some small leaking but nothing major. I've checked the ATF constantly and haven't gone down and am still at the correct amount.

About a week ago when my truck failed to shift I dropped it in second accelerated and shifted into drive, my O/D light came on and flashed. This was the only time that happened, when I got home I turned the car off, brought the computer outside, turned the Explorer on plugged it in and it didn't read anything other than the P0734.

And today at work when I was leaving at a stop sign in the parking lot I came to a complete stop, went to accelerate and all the engine did was rev. I put it in 2nd, still reved, put it in 1st it reved, tried reverse since no one was behind me it also reved (had no reverse), placed it in park, and then back in drive and it finally shifted. And then all the way home around the 35-40mph mark it would not shift unless I eased off the accelerator or dropped it in second then placed it in drive. Also when I got to another stop sign about a mile from home, came to a complete stop and then accelerated again, my Explorer made a rough bang sound when I pushed on the accelerator, a rough shift.


1999 Ford Explorer Sport
2WD
V6 OHV
139,000

Transmission has never had a problem, been rebuilt or been serviced in the past.

The employee at AutoZone told me to purchase this guy:

http://www.autozone.com/autozone/parts/_/N-6o3b6?itemIdentifier=28933_0_0_

And see if that fixes my shifting problem. I'm installing it tomorrow.

Was hoping for some other tips though in case this doesn't fix my issue.

 

[PopRichie77]

Well, I hope it fixes your problem but most likely it won't. You may have a blown valve body gasket, bad shift solenoid, bad epc solenoid, bad pump or blown clutch or servo seal. Do a pressure test first, both line and EPC pressure, then go from there.
Continuing to drive a slipping trans can cause more damage.

 

[thatoneguy]

The sensor definitely helped I have no issues shifting, I do have a rough idle now though and can still feel the truck shift hard at times, I'm just going to go down the list of things to resolve my issue. Thank you for the help

 

[PopRichie77]

That's interesting as that sensor only checks the speed of the output shaft. When stopped there is no pulse from that sensor, so it should not cause a no drive condition. Code P0734 refers to shift solenoids or an internal hardware failure, it does not mention the output shaft speed sensor as being part of the problem.

 

[thatoneguy]

Yeah the sensor helped for the first day but I think it was because the shop cleared the code on me which made the computer think everything was okay? No clue.. either way my wishful thinking got the better of me.

Yesterday the same problems happened only worse now I don't have reverse or drive, found that out on the way to work at a stoplight. Waiting for the light to turn green, when it changed I accelerated and was basically reving my engine. Put it into 1st and was able to pull off to the side of the road after a hard shift. Also found out I don't have a reverse. I can go in 1st and 2nd but if I'm in drive no luck what so ever.

I'm thinking about doing a transmission rebuild or buying a rebuilt one. Shops out here want at least 3 grand. I've found some online that a few members mentioned on the site:

http://800700tran.com/prod.itml/icOid/149

Question is; is a rebuilt worth it? I'm sure members on the site have done rebuilds but I'm wondering if they would recommend it? A friend of mine who also had an Explorer had a shop do his rebuild and a few months later it was shot. I'm at the point where I don't want to get rid of my Explorer because I love the thing to death, still my first vehicle lol, but I'm considering a new car. But with that comes car payments. Two months of car payments counts for the rebuilt transmission above, and my X is paid off.

Any suggestions ? :l

 

[PopRichie77]

This is my opinion. I would suggest dropping the trans pan, check the valve body bolts to see if they are loose. If loose the gasket is probably blown. Either way remove the valve body and look for a blown gasket. Also check the solenoids. If nothing is found, you can decide on rebuilding or buying a rebuilt. Rebuilding requires some special tools. You can improvise but you must have access to things to do this. The clutches are spring loaded and require pressing to remove the spring pressure in order to remove the snap ring. Also you should have a pump alignment tool to put it back together. If all you have access to is modest tool box, then I would suggest a rebuilt trans with torque converter.

If you have access to a pressure gauge, check the line and EPC pressure first. This will help with diagnosing the problem. Do this first.

 

[thatoneguy]

I'll do that, drop the trans pan check the bolts/solenoids and see if i have a blown gasket. I'll have to take it to a shop if I get a rebuilt transmission since I don't have the tools to complete it I also don't have access to a pressure gauge to check the EPC :/ would a shop do it?

 

[PopRichie77]

Yes, a shop could do it, but you might be throwing money away. I am going to send you a PM, check it.

 

[thatoneguy]

So I took my truck into a transmission shop today, leaving it there overnight. They're going to look at the transmission, gaskets, sensors, clutch everything for free. If I do need a rebuild its 950 out the door. The employee at the shop mentioned a shift kit if it turns out I need a new transmission. Any ideas on this or recommendations? This is the first of heard of it in all honesty.