TH 400 won't shift to 2nd or 3rd

[IndyRich]

Edit....Thanks to all who helped. I finally got around to messing with it and it was THE GOVERNOR!! Teeth stripped to nothing. A new Sonnax one $44 shipped to me,beats a rebuild


Hi everyone, so I'm driving home from Lowes and as I accelerate from a stoplight my truck (tranny) won't go fast than 25mph. It takes off like normal and then just revs higher when I hit 25mph and won't shift to 2nd or 3rd. I limped home and checked reverse, it works fine. No vacuum lines came off, fluid level was a little low so I added some, but that did not fix it. Would love to hear your input!
Questions:
1. What does the fact that 1st and reverse work mean? what can I eliminate because of that?
2. Some very small debris in fluid, what does that indicate?
3. If I pulled it to have it rebuilt, what is a "good" price for a TH400 rebuild?

Thanks in advance!
Rich

[Tom Vogel]

Originally Posted by IndyRich

Hi everyone, so I'm driving home from Lowes and as I accelerate from a stoplight my truck (tranny) won't go fast than 25mph. It takes off like normal and then just revs higher when I hit 25mph and won't shift to 2nd or 3rd. I limped home and checked reverse, it works fine. No vacuum lines came off, fluid level was a little low so I added some, but that did not fix it. Would love to hear your input!
Questions:
1. What does the fact that 1st and reverse work mean? what can I eliminate because of that?
2. Some very small debris in fluid, what does that indicate?
3. If I pulled it to have it rebuilt, what is a "good" price for a TH400 rebuild?

Thanks in advance!
Rich

Check the vacume line that goes from the back of the carb to the modulator on the tranny... if its cracked anywhere it wont shift. It would act just like that if the rubber line is old and brittle. Id guess thats it.

[67/72junkie]

Remove side cover and check the govenor.It has a plastic gear on the end and when worn bad it will strip the teeth and tranny won't shift.I have had this happen to me twice over the years with th 400.This is second thing to check after vacumn line to modulator and modulator.

[fine69]

Sent you a PM.

[ShredSled]

yeah, I was going to say the shift governer too... side cover should be on driver's side above the rear mount...

[Original67]

Originally Posted by IndyRich

Hi everyone, so I'm driving home from Lowes and as I accelerate from a stoplight my truck (tranny) won't go fast than 25mph. It takes off like normal and then just revs higher when I hit 25mph and won't shift to 2nd or 3rd. I limped home and checked reverse, it works fine. No vacuum lines came off, fluid level was a little low so I added some, but that did not fix it. Would love to hear your input!
Questions:
1. What does the fact that 1st and reverse work mean? what can I eliminate because of that?
2. Some very small debris in fluid, what does that indicate?
3. If I pulled it to have it rebuilt, what is a "good" price for a TH400 rebuild?

Thanks in advance!
Rich

#1 if I recall correctly are direct drive so nothing has to move to engage them is why they work.

#2 could be anything from normal wear (don't know when you changed it last) to a band coming apart. Hard to tell.

#3 this strictly depends on your location. There are people in OKC that will do it for as little as 300 up to 1K+ and it all depends on what you want in it.

[Tkmadone]

I second the vacuum line check. Happened to me once too.

[Duncan and son]

We have a guy in Lubbock (Jr Crump) that is the transmission daddy and if we pull it he rebuilds it and we put it back in he will do a complete professional rebuild on a turbo 400 for $450.
Hope that helps Paul

[Longhorn Man]

go fire it up and drive it down the road, put the shifter in first... not drive.
Get up to 20 - 30 MPH, and then place the shifter in second.
If it shifts, then look at that vacuum line again... moth ends of it.
If it doesn't shift, then look into the GOv... and local rebuilders.

[IndyRich]

Well thanks for the input, did all you said. Vac lines are good, but replaced them anyway. Tried the shift thing from first at 25mph then to second and nothing happened. SO it looks like a governor or rebuild.

[neba]

did you replace the modulator? what color is the fluid? if its brown it needs to be rebuilt. if not, other things to check.

[IndyRich]

Just an update....(I work on my truck in spurts. On two months, off another) Anyway.....it wouldn't shift or go above 25 mph.....IT WAS THE GOVERNOR!!! Thanks to all who gave suggestions. The teeth on the plastic gear were almost gone. A brand new Sonnex governor shipped to me was $44. Sure beats a rebuild!

[kwmech]

Sometimes the rear bushing in the case will move back thereby stripping out the nylon gear. Check the bushing before you reinstall the gov'ner