Hi guys,

New problem (big surprise) I noticed that when I'm in stop and go traffic, the transmission has no idea what gear to be in (either 1st or 2nd) and twice now the tachometer will bounce and the engine will rev and bog down between 800-1200 rpm if I coast.

It'll keep doing this until I give it more throttle, or brake to a stop.

Transmission almost always doesn't downshift to first unless completely stopped or rolling, so I have a feeling that when I'm coasting through stop and go, it doesn't know if it should be in first or second, so the engine revs up and down without me touching the gas pedal.

Any ideas what's happening? No codes...

 

Check the TV cable. My 97 3.9 wasn't doing exactly the same it just always wanted to be in 1st and i found my Tv cable was completely detached and broken. Fixed it and the problem went away.

Hope this helps :-)

 

Thanks for the reply Doug.

Unfortunately ive already tried replacing the cable and I have made so many adjustments to it and still unsuccessful.

Not sure its electrical related, or possibly have crud in my tranny clogging up the valve body.

Or it could be something completely different.

Damn Dak!

 

That sucks... it's always nice when the problem is right on top isn't it?

Did it get really cold the night before the problem started? I ask because when i don't warm my truck up in neutral (i guess the trans pumps don't operate in park?) I have to smooth talk my transmission into shifting into second on time... however mine does not bogg down that low before it finally shifts... once the trans fluid is good and warmed up, the problem goes away.

 

Doug, SxR had a little accident with a deeper-than-expected mud puddle a few months ago....It's been an ongoing thing with everything forward of the driveshaft.

I still vote that you need to get the trans checked out, because I'm about 95% sure you have mud in the valvebody or front pump still.

 

Magnet's right haha, I was in some deep water.

The tranny does perform better when its warmed up, it'll downshift if I'm going about 5mph or under. When its cold it wont downshift at all, or wont downshift until i'm stopped completely.

I want to get the transmission checked out but on the other hand Im very short on funds at the moment. I'm also weary of pulling the valvebody myself incase I make things worse.

I don't want to take it to a tranny shop and get the whole "Yeah you need a rebuild - pay me $500 now just for looking at it then more if you wanna rebuild it".

I'm considering doin a DIY flush and unhook the tranny lines from the rad and let the pump flush it out... what do ya think?

 

I think the valvebody is after the cooler, coming off the pump outlet and going into the rest of the transmission, so i don't know if flushing it that way would work.

I don't know how safe it would be to open the valvebody. The FSM doesnt say if you can just open it up, or if the springs will all come out- I'd imagine the check ***** would stay in place in their grooves. It goes together like a clamshell, just the top and bottom halves.

The best thing you could do, and I sure the hell wouldn't want to do it, but get the trans nice and hot so that all the crap in it is dissolved into the trans fluid, pull the fuel pump relay, let the engine die out of fuel, drop the pan, then spin the motor on the starter and let all the rest of the fluid come out of the system, put the pan back on, put fuel pump relay back in, burp the valvebody, and see what it does.

 

That sounds like a lot of room for me to screw up


Do you happen to know if its just the governor pressure sensor which controls the 1-2 shift? Cause I know NY truck is extremely quick to upshift, and extremely slow to downshift.

It'll upshift at 1500 to 2nd, and at WOT it up shifted at 2200 rpm.

2nd to 3rd upshifts at 2300 rpm and at WOT it'll upshift around 4500-5000.

Made so many adjustments to the TV cable in both directions and still nothing.

 

More research is pointing me towards the Output Speed Sensor which can cause similar problems according to a lot of jeep websites.

Its only a $40 part so one last possibility won't hurt..

If it fails then I'll live with it and wait for my clutches to burn up Lol.

 

I think I'd take it to a trannie shop. You've been messing with this for 3 months or so, and things are better, but not fixed.

It doesn't hurt to be upfront with the trannie guy. Describe the problem, tell him about all you've done to the truck (including the mud bog incident,) and tell him that you're kinda tap-city right now. A good local guy should be able to do a diagnosis for free or about $100. Telling people upfront that you're limited on funds is no crime, and quite often skilled technicians will work with you.

I think you need to get this resolved.