My First Transmission Problem P0734 & P0735

[Benji-Man]

First off, let me Thank in advance for any/everyone who takes the time to read and respond, in an effort to help diagnose my problem. I have read ALOT of the previous threads pertaining to others issues, yet haven't seen much reguarding my issues.

Vehicle Info answers:

1: Born 10/20/2000 Hazelwood, Missouri (2001 Ford Explorer XLT)
2: 4wd
3: V-6 SOHC
4: 154,500 miles
5: Trans fluid and filter changed every 30,000 miles, upto and including the 150,000 interval. Always done by myself, normal drop the pan, replace filter, and top off fluid. Never any strange findings and only minimal cling-ons to the magnet in the pan. Nothing else has ever been needed/done.

6: Seems as if fourth and fifth gear are not there. Reverse and 1st thru 3rd feel great, but as soon as trans shifts out of 3rd to go into 4th it just wraps up RPM's

7: Had transmission shop pull codes and got P0734 and P0735 4th and 5th gear ratio incorrect.

8: Yes, fluid level is fine.
9: Fluid color looks like when I poured it out of the bottle 4,500 miles ago
10: Changed fluid and filter 4,500 miles ago
11: Castrol Mercon V fluid was used
12: Absolutely no leaks from under my truck
13: No recent electrical problems, that I am aware of
14: Engine performance is as it has always been, no ill effects what so ever, no codes/no problems
15: 900 miles ago I added 31-10.50R15 BFG A/T everything else is bone stock
16: I have driven 700 miles on the new tires around St Louis no ill effects, I loaded the truck and trailer to go to SMORR a 4x4 off-road park close to Springfield MO. Had over-drive off and made the 230 mile trip just fine, still no ill effects. Played around at the off-road park, being gentle, small hill climbs in 4wd and the occasional mud hole. I never saw or felt anything out of the ordinary. Upon reloading the truck and trailer, now having less weight for the trip home. I pulled out of the 4x4 park and the truck shifted 1st-3rd just fine but when it shifted out of 3rd to go into 4th it doesn't grab that gear. It seems if you let the rpms rev up to 5000 which i only did only a couple time to see what would happen, it acts like it tries to pull but it is very minimal at best. After a couple of minutes of playing with the throttle trying to rev up and rev down trying to catch the next gear (4th) the O/D light started flashing. I dropped shift lever back into 2nd and got to the next town about 5miles away. Checked fluid level, it was ok, still no overheating issues, I'm stumped.

I kept the shift lever in 2nd and drove back to St Louis, running about 4000 rpm going about 60 mph for the approx. 200 miles back home. It seems as thou it is really shifting into 3rd with the lever in 2nd because i can't see going 60 mph in 2nd only turning 4000 rpm. Trans still has reverse and pulls very well 1st -3rd when lever is in Drive, but just revs up after 3rd. I do have engine braking when lever is in 1st or 2nd.

I have pulled all connectors on transmission to check for bad connections and found no change. I also got an inch/lb torque wrench and tried to see if the O/D band was adjusted properly or if it was broken. It was adjusted properly, I loosened to locknut and torqued to 120in/lbs and turned 2 full revs backwards. No Improvement

I'm Stumped PLEASE HELP

I'm cleaning out the Garage now so I can pull the truck in, just in case it's out of commission for a while while I work on it. Getting ready to pull the pan and see what I find. Just hoping for some insite as to what to keep and eye out for.

My plan is to pull the pan and filter, check solenoid retaining bracket for problems, check solenoids for resistance, then dive into the valve body if needed.

Sorry for the novel, just trying to give all the info I have.

Again any/all advise is welcomed and again THANK YOU in advance.

 

[35Remmy]

BM...The first thing I would do is what you have already cited...to pull the pan and look for anything out of the ordinary! Basics first.

 

[Benji-Man]

Update:

Last week I pulled the pan looking for anything out of the ordinary, like I would know what that was if I saw it. Then I made a cardboard punch -out of the bolt locations of the valve body and started removing bolts. When I removed the valve body I did see a few things that were likely the cause of my problems. First, I found a damaged gasket on the separator plate to transmission side of the separator plate. Second, I found an (end bore cap); don't know its correct name, which was very loose. Third, upon my curiosity taking over I started to remove the separator plate screws to see it that gasket was fine. One of the torx screws closest to the damaged gasket and located closest to the EPC solenoid wasn't even finger tight anymore. I read on EF that the EPC operates at a certain frequency and that it can and have vibrated bolts loose. I have attached images of my findings.

I too called Donnie at Central Valve Bodies and had a Rebuild valve body FedX'ed to me. 12month/unlimited mileage warranty with the Sonnax upgrades for 247.49 total. I locally purchased the double wiper o-ring for the reverse servo and a new servo plate gasket. I purchased 8 quarts of Castrol Mercon V and a new filter and gasket. Then went home and got very intimate with my truck, and yes there was petroleum jelly around.

Upon pouring the new Mercon V in the truck after about the fifth quart, I double checked under the truck to see if anything was leaking and yep WTF? Seems as though the Missouri winter salts have not done my transmission fill tube well. It had three different small hales in it from rust. Yet another trip to the JY and they didn't even charge me for the filler tube.

I have already put 700 miles on since the upgrade and couldn't be happier, Knock On Wood.

All-in-all, I can't complain, 154,000 miles b4 my first transmission related issue and its already fixed.

THANK YOU AGAIN, EXPLORER FORUM AND TO ALL OF THE KNOWLEDGED PEOPLE THAT MAKE IT WHAT IT IS !!!!!!!!!

 

[Oxygen]

nice work!

i have almost 190,000 miles on my stock transmission..

but of course its on the way out.... i started to get the flashing o/d light last friday... this is the second time of me getting the flashing o/d light, i had it about 2 years ago, and then it went away... and now its back!!

i don't understand because when the transmission is running great when the o/d off light is not flashing.... so how could i need a rebuilt tranny if mine shifts smooth as butter when its working good?

i think its something electrical...