Strange Transmission Issue

[Trendeman]

I have a 2007 Explorer 4WD, 4.0 with 260,000 miles on it. When I start it in the morning and put it in reverse, I get a fairly loud whirring sound. I put it back in park (sound stops) and then back in reverse and it goes into reverse as it is supposed to. After backing 20-30 feet, I hear a "thunk" and the vehicle operates normally the rest of the day. I took the vehicle into a transmission shop and had diagnostics run and the transmission fluid changed. All diagnostic tests were clean and there was no metal or other debris in the pan. Although the mechanic heard the whir and thunk, he could offer no explanation of cause. After having the fluid changed, everything went away and operated normally. Until today. I drove to Atlanta on the interstate (about 130 miles each way) and when I would let my foot off of the gas, it would feel like the transmission disengaged, RPMs dropped, and I would get that loud whirring sound. It reengaged and the sound disappeared when I accelerated again. It does this with overdrive engaged and disengaged. Took it to another transmission shop and their solution was to replace the transmission. Hate to do this with it operating smoothly and normally (no slippage, shifts through all gears...) in all other ways. Any ideas out there?

 

[Beachcomber86]

Sounds stupid, but check your wiring harness for bare wires. Check out this thread.

http://www.explorerforum.com/forums/index.php?threads/found-my-ghosts-in-the-machine.415084/

 

[tripplec]

When cold the tranny fluid is at its lowest. Check the fluid level to see if its at the spec's as per the dipstick and temperature for testing. It maybe low if a small leak exists. Always the first thing to check, at least if there is a dipstick. Its easy, the manual should specify the procedure for you.

 

[Explorer_PL]

No dipsticks on v6 or v8........

 

[tripplec]

Oh, I know the V8 doesn't. Oh well if it isn't leaking maybe something else then.

 

[Trendeman]

Sounds stupid, but check your wiring harness for bare wires. Check out this thread.

http://www.explorerforum.com/forums/index.php?threads/found-my-ghosts-in-the-machine.415084/

I'll do some looking for bare wires. Thanks

 

[Trendeman]

When cold the tranny fluid is at its lowest. Check the fluid level to see if its at the spec's as per the dipstick and temperature for testing. It maybe low if a small leak exists. Always the first thing to check, at least if there is a dipstick. Its easy, the manual should specify the procedure for you.

No dipstick to check. No evidence of leaks anywhere on driveway or transmission. The transmission quit doing "strange" things after I had the fluid changed but it only went away for about a week before it started doing the same thing again.

 

[tripplec]

Well its very hard to say. Do you know if the old fluid was burnt, brown or what state.

Was it the original fluid in it still (I see you have 260k on it). If so another drain and fill may do it. If a flush is done it can cause problems especially at high millage!!

Also was it done at a dealer? If not what fluid did the place use. The right fluid type is critical.

 

[Beachcomber86]

... The transmission quit doing "strange" things after I had the fluid changed but it only went away for about a week before it started doing the same thing again.

I swear this sounds like mine. I first thought it was an engine stumble and then the torque converter slipping. Once I covered the bare wires in the harness to the MAF, Distributor, etc. voila...no more weird transmission issues.

 

[Trendeman]

Sorry, I've been out of town on travel with no computer access. After a lot of troubleshooting and help from the forum, I threw my hands up and paid the $135 "diagnostic fee" at the dealership. It turned out to be a bad transfer case. Had the transfer case replaced and all is well. Thanks for everyone's help.

 

[Trendeman]

Well its very hard to say. Do you know if the old fluid was burnt, brown or what state.

Was it the original fluid in it still (I see you have 260k on it). If so another drain and fill may do it. If a flush is done it can cause problems especially at high millage!!

Also was it done at a dealer? If not what fluid did the place use. The right fluid type is critical.

I had the transmission flushed and fluid changed when I bought the Explorer with 243,000 and was told by the mechanic that the fluid he replaced was not burnt or discolored. Turned out the transmission is fine and the problem was in the transfer case. Replaced the transfer case and all is well.

 

[Trendeman]

I swear this sounds like mine. I first thought it was an engine stumble and then the torque converter slipping. Once I covered the bare wires in the harness to the MAF, Distributor, etc. voila...no more weird transmission issues.

Solved my issue by paying the dealer a crazy diagnostic fee and finding out it was the transfer case and not the transmission. Had the transfer case changed and solved the problem.