Funny? Tranny question

[da2962]

Looked through the forums and did a search but didn't find an issue exactly like I experienced. The other day, headed out for work as usual, as I was heading down the hill from my house all of a sudden the engine started revving (hit about 5grand on the tach in Drive) with no noticeable increase in speed. Felt like the tranny was slipping. Immediately took it over to my usual mechanic, he took it for a ride and said he didn't feel any problem, was shifting normal. Since his lifts were full told me to bring it back Monday (today). So just to test it out, yesterday, had a nicer day warmth wise so let it warm up for about 10 minutes and headed out through the neighborhood. Ran just fine, shifting normally. Same this morning, was in the upper 20's, let it warm up for about 10 minutes and it worked fine. Took it in so he could check the fluid and levels were good and fluid looked fine. He told me he did notice a slight hesitation going into reverse, and I have noticed it myself in the past, though not that bad that I gave it much thought. He also hooked it up to the reader and got no codes from it and I didn't get any warning lights that might have been related to it. So, any guesses what should be checked? Could it have been cold related (was in the low teens the morning it gave me the problem, though I wouldn't think that would be an issue). Supposedly the tranny was rebuilt just before I bought it last year, but the warranty on it was up about 10 months ago. Its an 03 XLT 4.0 with just over 92,000 miles on it. Its got me concerned since my last Exp (a 94) had to have the tranny rebuilt and ended up costing me around 2 grand. Don't want to go through that again. One of the reasons I bought this one was that the tranny had already been rebuilt since I know this is a weak spot on the X's.

 

[imp]

Looked through the forums and did a search but didn't find an issue exactly like I experienced. The other day, headed out for work as usual, as I was heading down the hill from my house all of a sudden the engine started revving (hit about 5grand on the tach in Drive) with no noticeable increase in speed. Felt like the tranny was slipping. Immediately took it over to my usual mechanic, he took it for a ride and said he didn't feel any problem, was shifting normal. Since his lifts were full told me to bring it back Monday (today). So just to test it out, yesterday, had a nicer day warmth wise so let it warm up for about 10 minutes and headed out through the neighborhood. Ran just fine, shifting normally. Same this morning, was in the upper 20's, let it warm up for about 10 minutes and it worked fine. Took it in so he could check the fluid and levels were good and fluid looked fine. He told me he did notice a slight hesitation going into reverse, and I have noticed it myself in the past, though not that bad that I gave it much thought. He also hooked it up to the reader and got no codes from it and I didn't get any warning lights that might have been related to it. So, any guesses what should be checked? Could it have been cold related (was in the low teens the morning it gave me the problem, though I wouldn't think that would be an issue). Supposedly the tranny was rebuilt just before I bought it last year, but the warranty on it was up about 10 months ago. Its an 03 XLT 4.0 with just over 92,000 miles on it. Its got me concerned since my last Exp (a 94) had to have the tranny rebuilt and ended up costing me around 2 grand. Don't want to go through that again. One of the reasons I bought this one was that the tranny had already been rebuilt since I know this is a weak spot on the X's.

My GUESS would be that a poor electrical connection exists at one of the harness connectors feeding power to the transmission, possibly to a Pressure Control Solenoid, which allowed the transmission fluid pressure to drop to a level allowing slippage. This SHOULD have generated a trouble code, but, some codes do not get displayed until the malfunction REPEATS a certain number of times. A one-shot loss of pressure might cause this problem.

Or, I'm full of ****! But as a start, I would disconnect the harness feeding the solenoids at the transmission, spray some good electrical lubricant into the connector, and re-connect it. Drive awhile, see what happens.

Without a trouble-code for guidance, any intermittent fault which happens one time is a BEAR to try to pin down. IMHO, of course! imp

 

[da2962]

Thanks for the reply, the mechanic said the same thing, that he's seen problems happen once for no reason then never happen again making them almost impossible to diagnose. I'm taking it in in another couple weeks for an oil change so while its up on the lift I'll have him check the connections. If I get any more info I'll pass it along.

 

[da2962]

Well, after a few days of driving with no issues, had to head out of town for a job today, and after about 10 miles, had the same issue. Would rev with no power, I'd downshift into 3rd and it seemed to smooth out, then back into drive and after a few minutes same thing. Didn't want to risk it so drove it home to get the car and it shifted smooth and fine on the ride back to the house. This is starting to become annoying since this is my work vehicle and I need it to be relatively dependable. Gonna call the mechanic to let him know it happened again and to see if he can hook it back up to the reader to see if it shows any codes this time. If not I'm stumped. Don't really want to go to the dealer ($$$$). Only other thing I can think is to take it to a transmission shop but don't really know any that I would trust without reservation to tell me the truth and not just rebuild it for the cash. I know that sounds pretty cynical but I've heard too many horror stories not to be nervous. Any other thoughts on what this might be?

 

[EasyRhino]

(disclaimer - I'm no tranny guru), but I have been reading about Gen 3 trannies for awhile, as I'm nervous about mine lasting, and have not read this type of problem before.

I gotta go with the bad electrical connection theory at this point. Since the tranny was previously pulled, the connections may not be made up as well as intended.

Good luck and let us know what you find.

Oddly my 2002 Limited hesitated going into first from a stop when it had less than 5000 miles on it and never repeated the problem. Weird.