Too high rpm before shift to 3rd

Hi to you all.

I just had my TH400 overhauled.
The shifting improved a lot. It became much smoother, no slip, etc.

The last days I noticed that I need a very high rpm & speed, (120 km/h) before it shift to 3rd, if att all. (It feel like the transmisson are in kick-down mode).
Occationally it "loosen up" and shift.

I have checked the kick-down switch, (on the accelerator), and this seem to working without being stuck.
Is there any simple way to check the function of the kick-down solenoid inside the transmission?

Per.

:beer :beer

 

I don't know what gear ratio you have, but if I remember correctly 120 km/hr is about 80 miles/hour, and that seems like a decent speed for a 2-3 shift. Do you know what RPM that equals?

-Bob Cunningham

 

Hi Bob.
Thanks for reply.

I do not know the RPM, but the engine is screaming and I am getting worried that the fan will "take off". :ball:
This is during normal cruising, not WOT, so change at 80 mph sounds fare to high in my opinion.
I would believe you should be able to cruise comfortably in third gear at 50-55 mph?

I have a feeling that the kick-down solenoid inside the transmission are occationatly getting stuck.
Is it possible to check the solenoid without opening the trans., and have anybody experienced same problem?

Per.

:beer :beer

 

Often after a rebuild, a piece of debris will find it's way into the governor, causing it to stick. HERE'S a good thread explianing what to look for and how to clean it.

Sometimes, shifting the trans manually from a stop will help free a stuck governor valve.

 

If you disconnect the wire to the trans, if you put 12v to the connector on the trans you should be able to hear the soloniod click. You should only have 12v coming through the wire at WOT. These checks should pinpoint your problem. Also, check to make sure the vacuum line from the intake to the modulator is intact. If disconnected, this will cause very high shift points.

 

My vote is for the vacuum modulator being bad or the line being disconnected at either end.

 

check everything to do with vacum, all the lines on the engine down to the trans, sounds like a leak somewhere

 

Thanks guys.

I'll try to get it to a shop this week-end.
(I am too fat to get under it in the garage).

Will be back with the result, (if any).

Per.

:beer :beer