Tranny Refuses To Go Into Reverse Periodically

[diceccon]

I have a 1998 Explorer XLT V6, 2/4wd and 120k miles.

Needless to say, I love the vehicle.

This has been an ongoing problem of mine that no mechanic has been able to diagnose, let alone fix.

When I shift the car into reverse, about 1/10 times it will make a crunching sound and sit in neutral. When that happens it is very difficult for me to get into reverse, only by waiting and switching gears many times. I am usually able to get the car into reverse eventually. If it doesn't make that noise then it functions perfectly, and it will continue to function perfectly for that time period.

I have found that when I rev the engine in drive with the brakes on before switching to reverse, I can lower the chance of the problem to about 1/100.

With a mechanic we dropped the pan in the tranny and found that there was minimal metal attached to the magnets, that was the first time that I have changed the fluid since getting the car. We found that the filter was missing an O-ring and was just hanging inside the car. After replacing the filter and the fluids it appeared that the problem had been fixed: low pressure in the transmission. Heating up the fluids seemed to generate enough pressure to switch into reverse.

For about I week I did not have any problems, until I did. The same exact problem, and it cannot be an issue with the filter, unless the new filter is faulty, which I highly doubt.

What's going on? I'm taking my explorer back to the mechanic in a couple of days and I doubt he'll find anything without a direction to look. (He's an AAMCO tranny technician, he should know what's going on - and this is his last chance, if they miss it again I'm done with them.)

Also, how much are we looking at? The problem doesn't seem regressive, but how could I know? If it isn't then I'll just let it be, but if it is I'd rather address it now because I'd love to get 200k out of this car.

Note: The blinking O/D does not come on when the problem persists

 

[my98nnj]

When I shift the car into reverse, about 1/10 times it will make a crunching sound and sit in neutral. When that happens it is very difficult for me to get into reverse, only by waiting and switching gears many times. I am usually able to get the car into reverse eventually. If it doesn't make that noise then it functions perfectly, and it will continue to function perfectly for that time period.

I have found that when I rev the engine in drive with the brakes on before switching to reverse, I can lower the chance of the problem to about 1/100.

Somebody correct me if I'm wrong, but doesn't the fact that when he revs it and it works point to an issue with the transfer case not the transmission?

 

[jplinville]

Correct...I just picked up a rebuilt tranny because of this issue. The guy I bought it off of had the tranny redone due to it not going into reverse. When that didn't work, he replaced it with a JY tranny...only to find that it didn't fix the problem

He had it brought into the prison garage (he's a guard at a prison in OH) and had the inmates look at it. They determined that it was the transfer case, and not the tranny.

So...after a year of sitting, he sold the rebuilt tranny with less than 10k miles on it to me for $100!!

I'd like to add that all the work prior to the prison garage visit was done by three different tranny shops...none of them thought to look at the transfer case.

 

[drdoom]

Well definitely if you have done your first transmission filter replacement you should change the fluid in the transfer case also. Have a good look at that fluid when you drain it. And if you are back in the transmission pan, check the torque on the valve body bolts, and check the band too. A pressure check should be considered as well. That transmission you have, it is well known for valve body gasket failures, issues with the reverse servo seals, and valve body bore wear. That transfer case you have, it is well known for shift fork related failures, shift rail bore wear, and range collar wear. Search around here a bit, there is a lot of good info.