C6 slipping second gear

[SuperDave]

Hello all, got a problem with my idi swapped bronco, out of nowhere second gear has started slipping and I don't mean a little bit I mean it's bad. In the year I've had the truck on the road the transmission has not given any indication of problems whatsoever but I drove it to town the other day and it did fine all the way there and I ran errands in town for about an hour while the truck sat still. When I loaded up and left town the trans immediately started to slip second along the towns streets leading to the main road and when I pulled out onto the main road it slipped bad enough I pulled over to check the fluid which was full and clean. It got to the point I didn't think I was going to make it the 4 miles home but once I got past all the traffic lights and could maintain 45mph or more it did fine. I'm a bit confounded by this because normally automatic transmission issues come on slowly and this happened all at once like something internally broke. Any ideas anyone?

 

[IDIBRONCO]

I'm no transmission expert, but since it came on suddenly, I don't think that an external adjustment will be the fix. It wouldn't hurt to try though. I'm afraid that you're right and it an internal problem.

 

[Big Bart]

Anything out of the norm? Some thoughts before you get thinking its time to come out.

1) Hot day?
2) Did it sit around idling the whole time?
3) Maybe its getting (Or due to conversion) stuck in between D & N or D & 2?

If not it sounds like it is either not building pressure (Bad seal or o-ring), delivering pressure (Pump is going out or has a clog.), or switching pressure (Valve body.)

I would not keep driving it if slipping. You are likely to do more damage and burn up a part or two.

 

[gnathv]

Did you try to adjust the band in it? Does it slip if you manually put it in 2?

 

[riphip]

Check the VRV setting & vac hoses.

 

[franklin2]

I have had them suddenly mess up from the kickdown linkage being in the wrong place. I didn't have it hooked up, and it worked itself around to where it was activated all the time, and it would not shift correctly till I found that and tied it into the correct position

 

[SuperDave]

Anything out of the norm? Some thoughts before you get thinking its time to come out.

1) Hot day?
2) Did it sit around idling the whole time?
3) Maybe its getting (Or due to conversion) stuck in between D & N or D & 2?

If not it sounds like it is either not building pressure (Bad seal or o-ring), delivering pressure (Pump is going out or has a clog.), or switching pressure (Valve body.)

I would not keep driving it if slipping. You are likely to do more damage and burn up a part or two.

It was a very hot, humid and muggy day with an ambient temperature of ~95 degrees. I did not leave it idling while I was in town and as a matter of fact it had cooled to around 140 degrees by the time I got back in it to leave.

I'm not driving it because I certainly don't want to tear it up more, of course if I find a problem and repaired it I would attempt a test drive but I suspect it's something like a broken band.

 

[SuperDave]

I have had them suddenly mess up from the kickdown linkage being in the wrong place. I didn't have it hooked up, and it worked itself around to where it was activated all the time, and it would not shift correctly till I found that and tied it into the correct position

Franklin, I will be sure to look at that, I removed the kickdown linkage a long time ago because it would downshift to second at 60 if you gave it just the slightest bit of throttle to maintain speed uphill. I got worried it was going to tear something up so I just removed the linkage. We will see.

 

[Cubey]

'Im not driving it because I certainly don't want to tear it up more, of course if I find a problem and repaired it I would attempt a test drive but I suspect it's something like a broken band.

I have heard there is a repair band that can be installed without pulling the transmission. You have to remove the valve body, cut the old band to remove it, then the new slips in and clips together.

 

[spg]

If you can drive it and get it into 3rd gear then pull the shifter manually to 2nd. If it downshifts the band is OK.

 

[264WSM]

Where are you? I have a spare for 4wd

 

[ifrythings]

It isn’t uncommon for the apply servo seal to go rock hard and loose a piece of itself, the servo is what applies the band for 2nd gear, you can pop the cover off and check it out without opening the trans.

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[SuperDave]

Where are you? I have a spare for 4wd

West Georgia right off I-20

 

[SuperDave]

It isn’t uncommon for the apply servo seal to go rock hard and loose a piece of itself, the servo is what applies the band for 2nd gear, you can pop the cover off and check it out without opening the trans.

You must be registered for see images attach

That's a definite possibility, the engine and transmission had been sitting since 1999, I'll pull the servo cover off and check that before I pull the trans. I have thought about building the trans myself but I have a friend that built transmissions at a Ford dealer for 30 years and charges $250+ parts. I just can't beat that.

 

[IDIBRONCO]

I have a friend that built transmissions at a Ford dealer for 30 years and charges $250+ parts. I just can't beat that.

That's a steal right there.