Th400 no 3rd all the sudden

[bobtail]

The old truck sat for about 2 months while I changed out the water pump and some repair to alternator & ps pump. I got her back together and took it out for some errands to make sure it was running good, came home on the highway and ran at 4k rpm for about 5 minutes for a few mile stretch of turnpike water temp 190-210. I was testing a problem that my long alternator bracket bolt was shearing off at the head at about 1 mile into highway speeds/3k rpm, but I have noticed fair amount of heat from above trans in cab.

So the next day I start her up and head out to the big truck, water temp at 190 when I backed out the driveway, go down to stop sign fine, accel to 35 and it doesn't shift, foot off gas and it coasts down to speed. (I have a feeling something was going and my highway test did it in)

Next day I replaced the modulator, kept the old one as I don't think it's bad, no change and blew metal vac tube with air so not clogged. I don't have a gauge to check vac.

That's where i'm at now, in a few days I'll look at governor as its easy and worth a try, but anyone think I blew a seal?

And sorry hotrodpc, I think I pm this to you on accident!

 

[bobtail]

Checked the governor, it looks a lot better than I thought it would and gear is perfect shape.

 

[gmachinz]

Is reverse ok? Reverse and 3rd use the same planetary gear set-typically when one goes you lose the other too.

 

[bobtail]

Yes reverse is good.. I just read someone with this problem, shift linkage was off adjustment. I may be over thinking this because shifter has always been real loose between neutral and D, and in D the indicator actually sits between D and 2. Next chance I get I'm going to go that route, what's involved to put the shift linkage to factory adjustment, parts replaced or just tighten bolts?

 

[HotRodPC]

Manually put the trans in N. Then put your shifter in N. Connect the linkage and tighten. Once you know N is exactly where it's supposed to be, then all selections in front of and behind N should also be lined up. Though I really doubt this is the problem.

I can't find my flow charts and diagrams to even guess at it right now. Just for giggles, take the kickdown wire off the solenoid on the side of trans and take it for a drive. I doubt that it's either since it's not shifting late to 2nd but weirder things have happened. Just wanting to make sure you don't have power to the kickdown solenoid like a defective switch at the gas pedal.

 

[bobtail]

I'll try the kickdown first, it won't be for a couple days though

 

[bobtail]

Well crud, would you mean this thing not connected? I'll try to post image below

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https://postimg.org/image/bu5t5dn1j/

 

[bobtail]

I just spent the morning manually engaging trans with column shifter unhooked. D is definitely not going into 3rd, or it may be stuck in 1st. At 15 mph there is no shift just increase in rpm but I did replace the modulator so it may be set too low. I turned it 1 turn clockwise to rev higher. That didn't help, I think I have first only. Reverse works fine still

 

[HotRodPC]

So now you're saying you don't have 2nd either? If you don't have 2 or 3, you know the Vac mod and Governor are good, I'd be going with the Forward Clutch Pack or Direct Clutch pack is worn out. Can't say without my charts and I can't find **** right now.


Yes, you're kickdown solenoid is NOT hooked up, so that's not what's stuck.

 

[bobtail]

Well I checked adjustment of the shift linkage, it seems loose in the column, solid clicks from trans into place no play. I had to get back to work today so I drove it on back roads, flooring to about 5k then down into neutral. I did this about 4 times, came to a stop sign in D, took off and the darn thing shifted at 15 mph, then again at 30! It worked again I don't know if it was just stuck in 1st or what but next time I drive it I'll let you know if it still shifts. I think it may need to be looked at still just to make sure.

 

[bobtail]

It is slipping in & out of reverse.. but other than that now it shifts like butter, like grandma's cadillac Deville. It used to rev higher into 3rd and chirp the tires with pedal to floor, I'm guessing that's the new modulator with the red stripe I think I read somewhere those are built different?

 

[HotRodPC]

I've been in and out. But did this ever come to any kind of resolution?

 

[HotRodPC]

Earth to Justin. Come in @bobtail . How you doing on this transmission? Where you at with it now?

 

[bobtail]

It's doing great, I adjusted the modulator, turned the screw towards trans about 4 full turns and now it shifts at about 3k rpm. I don't think it was a bad modulator, just seemed like 2nd gear was stuck or something since 1st and reverse worked fine. Took a few times wot shifting to neutral from about 5k rpm and after a stop it shifted fine. I shifted fast from 1 on the tree all the way to neutral, quickly passing through 2 and D, not wot in D up to N. Don't know if that makes a difference for anyone that may reference this in the future

 

[HotRodPC]

So you really didn't fix anything, but it did have an obvious glich. Sounds like you got a little agressive with it and did some manual up and down shifting moving the manual valve, and also opening other paths in the transmission that normally aren't used like Manual Low, Manual 2nd etc. Chances are it had a hung up valve or clot of junk in the valve body. You freed it and pushed whatever it was on through. Hopefully if that was the case whatever it was will get caught up in the filter and not have a problem again. If you can find a flat magnet of fairly good strength, even if it's off an old car audio speaker, put it on the bottom of your trans pan. No need to drop the pan. If it's a strong magnet just put it in the bottom of the pan this way any metal particles or debris will move to the magnet and keep it at the bottom of the pan so it doesn't get picked up and pumped back through the fluid. I'd try to keep the magnet toward the right rear of the pan to stay away from the electronic kickdown solenoid and the actual actuator for kickdown that's near the front left corner of the pan.

Also, now that you know your kickdown isn't hooked up, look for the orange wire under the truck and see about hooking that up. Also look under the dash at the throttle pedal linkage and see if you have the gas pedal switch and wires hooked to it.