Dual exhaust build, '83 GMC pick-up

[tRustyK5]

I agree, not supposed to lock up in 2nd....

Might be a diesel feature only, I may have to do a vid so y'all can hear it yourself. The exhaust note makes it really clear. It actually makes puttering around town a lot less good than it should be, once the convertor locks, it takes almost 3/4 throttle to get it to unlock, or brake input or 0% throttle.

Paul, I had to 'set' the TV cable on my '90 3 or 4 times to get it to rachet out the way it was supposed to. The diesel pick-up is not horrible, but it does shift too early right now at all throttle levels. i'm thinking the cable stretched a little or who knows...but currently at WOT it shifts at ~2500 rpm. It really should be holding to ~3200 or so at WOT.

I do know a guy that is the 'go to' tranny guy at a large and very busy GM dealer here. He actually did the provincial inspection on this truck when I first bought it. I may call him up and pick his brain a little.

 

[tRustyK5]

That truck always shifted funny, but it's got the factory 700r4 and who knows how many miles on it now, including several thousand miles of towing and hauling across the Canadian Rockies.........

Rene: I tried playing with the TV cable to fix the shifts, and always set it back to where I found it because there didn't seem to be a sweet spot anywhere....

It currently has 263,700 km on it. i've put almost 50,000 on it since I bought it from you.

 

[79rustyk10]

Might be a diesel feature only.

I am 98% sure it isnt, I wonder if there may be some sort of issure with the lockup solenoid causing it.

edit~ Do you have a tach in it?

 

[tRustyK5]

No tach...

I guess what would be ideal is a little light that comes on when the TCC solenoid is energized.

It's clear when you drive it around town, typical 5-10% throttle you get a noticable drop in rpm at the 1-2 shift, then almost immediately after that you 'feel' and now hear the TCC lock and get a corresponding slight drop in rpm (and exhaust tone)...next up is a clear 2-3 shift.

 

[tRustyK5]

I am 98% sure it isnt, I wonder if there may be some sort of issure with the lockup solenoid causing it.

edit~ Do you have a tach in it?

Googling some, and finding plenty of other supporting info that lock-up in 2-3-4 behind a diesel is correct.

Also found this for adding a TCC lock-up light, as well as some manual control

rene

 

[79rustyk10]

Damn, I learned something today I guess. seems to be some OK info in this thread.

http://www.dieselplace.com/forum/archive/index.php/t-270300.html

Wasnt trying to doubt you, I had quite a bit of experience with 700's a while back when I was killing them yearly, and had never heard of 2nd gear lockup before.

 

[79rustyk10]

IMO, I would probably disable 2nd gear lockup. My understanding the lockup function is to lower temps and RPM at highway speed. What is the point of locking and unlocking the converter any more than absolutly necessary, and creating more heat, especially in a gear you are only in for a few seconds at a time.

I also dont remember 3rd locking up right away for me, but that was with a TBI 350, completly different animal. In normal acceleration (from what I remember, its been a few years since Ive driven a truck with a 700r4) the clutch would only lockup once I reached cruising speed, and after it had shifted into OD.

 

[diesel4me]

Rene,the fact diesels have 2 batteries kind of sucks,as you mentioned,if one isn't 100%.it kills BOTH of them!..I know they are supposed to be "matched pairs" too,or you may have troubles,but I've had one Duralast "gold" and one Duralast "plain jane" batteries in my '82 K2500 since I got it in late '03,and they were not exactly "new" even then,and I have been surprised they held up this long..
...(watch,now that I said that, they'll croak on me!--as I type this,my Suburban has the charger hooked to it,the temps dipped below 40 again here Sunday night,so it didn't want to fire up ,it lookes like it'll need glow plugs or ether if I want to be able to start it and move it around in the cold weather)..

I think I read on a website how to "delete" the 2nd gear TC lockup on a 700r4 ,I dont remember where though--maybe one of the better tranny rebuilders can give you the info on how to go about doing it,it'll likely involve valve body alterations..