JD730

I'm having delayed lockup on my 47RH. It should lock as soon as I hit my mystery switch, but it may take a few miles till it locks up. Especially if it cold out, like the 50 degree mornings we've been having here.

I would guess that something is hung up in the valve body.

I just got it back from the trans rebuilder, there isn't even 200 miles on it yet, they rebuilt it again under warrenty after it smoked the low/reverse band out and cooked some clutches. They said something had cracked in the valve body and it was loosing pressure interally.

Anybody had similar experiences with this or know what to do about it. I'm really getting tired of taking my truck back to this shop. This will make it the 4th trip back.

Thanks
Mike

infidel

The trans temp has to be over 70F before the PCM allows lockup even with a mystery switch.
Not sure which year you have but if the sender for an aftermarket trans temp gauge is is in a tee with the stock sender rather than in the fuild flow it can take a long time for the PCM to see 70°.

JD730

The trans is in my 93, its from a wrecked 95. So the PCM doesn't even have a clue about trans temp.
When I hit my switch it energizes the selinoid for the lockup, there is nothing else to stop it. I wired it right to the trans.

I also had it do it when it was warm once.

WildBill

I have seen a bad converter do that, sometimes it would lock up like normal, sometimes had a delayed lockup or no lockup, even when testing by directly grounding the lockup wire like you are doing with the mystery switch. (new converter cured the problem)

JD730

A little update:
My brother returned from school with the truck today. No lockup at all. Electrical circuits for both lockup and OD test good.
I tested the pressure at the accumlator port, 32-35 psi at idle(is this a little low?) in drive and up 150-160 psi driving down the road WOT.
Also OD shifts in and out rapidly sometimes, but that could be my PCM doing that. A temperary switch for testing would solve that.

got...DIESEL?

I had a tripleloc that would not lock if the trans throttle valve was open more than a third. I ported the switch valve bore thinking it would improve it....no dice. In the end, Clint agreed with me an sent a new converter.....that particular problem went away.