DodgeFreak

I rebuilt a transmission in a 98 12valve 47re and everything works good it has a transgo shift kit in the valve body. It shifts firm and everything except when you manually shift the truck the 1-2 shift is fine then the 2-3 shift flares at wot. What could cause this. In drive it shifts fine at wot? is the band not holding? This truck has a few engine mods done to it also. torque plate, quick spool housing, delivery valves and injectors, banks twin ram, and i'm not sure what else. I've rebuilt a others with out this problem. But i'm also fairly new at rebuilding transmissions and i know there's guys that's been at it alot longer than i have. THanks for the help DF

oldblues

hi
flaring up going to 3rd sounds like a clutch pack prob ?
what fluid did you use ?
what is the clutch pack clearance ?
maby add some more line psi ?
is your throttle psi cble cable set properly?
what is your front band adustment set at ?
do you have the proper fluid level in N sitting level engine running ?

DodgeFreak

I'm not 100% sure whats in there now as its my cousins truck and i ran ATF4 in it and told him to break it in with that then change it. His dad (who use to rebuild chrysler trans) was using a hyd. oil with lubeguard in it and was running it that way for along time till he passed away and gave the truck to his son, and my cousin wanted it rebuilt just so it will hold up to the power so its either atf 4 or hyd. fluid with lubeguard. The clutch pack clearance is all at the tight end of the clearances. the throttle valve cable we played with and adjusted to how the book said but also played with it just by trial and error and still nothing. Front band is adjusted to what the Transgo shift kit said. can't remember exactly the specs. Fluid level has been checked countless times. and as for the line pressure the Transgo shift kit said to go 4 turns with it and the first time i went 5 turns with it but then when you went to wot it wouldn't come out of 3rd till you backed off the throttle so when i turned it down to the 4 turns it fixed that problem. All the line pressures and Accum. pressures are good they are just alittle high but i was told that was probbaly because of the higher line pressures. If its a clutch pack problem, then why is it only going from 2-3 manually that it does it and not when its in drive? Just wondering because thats what has me stumped. Thanks for the help.

jimbob1111

Hi,
I used to rebuild transmissions @ Jeep dealer before back sugery, it's been a few years but.
In second you have the front band holding, rear clutch applied.
When you shift to 3rd it releases the front band and applies the front clutch, rear clutch stays on.
It could be a shift timing issue, or a slipping front clutch.
The front clutch should not apply until the servo for the front band dumps pressure or the trans would lock up momentarily.
Your best bet would be to use some pressure gauges and drive to duplicate the condition and see if you have correct apply pressure to the front clutch while its flaring. In my experience you want the front clutch pack on the high end of the clearence, if memory serves correct, in 1st gear the clutch discs are turning one direction and the plates the are going the other way. Years ago a friend of mine tightened up the front clutch pack clearence WAY below spec and it sucked all the power out of a 440 drag car in 1st gear, and smoked the front clutch after 1 run.
If you have correct apply pressure on the front clutch pack and it's flaring, it must be slipping. if you don't have correct apply pressure while it's flaring, it's most likely a hydraulic timing issue or a hydraulic pressure leak on the front clutch circuit.
Duplicating it with the gauges on it is the best way to track it down.
just my 2 cents,

DodgeFreak

Alright sounds good. I know the clutches are on the tight end of the clearances. If the front clutch is leaking or slipping why does it only do it when you manually shift it. If you let it shift automatically it shifts real firm no slipping or anything??

jimbob1111

Hi, I just got in, spent all day working on a friends ford t-bird I hauled home on the trailer last night.
I took a look in my 727 rebuild and modification book, it doesn't have that in the diog. charts, I go into work at 7pm mon, I'll see if we have a 98 BR manual, the factory manual might have some info on a manual 2-3 flare shift. You might want to call the Transgo folks tomorrow see what they say, most of my trans rebuilds were stock rebuilds, no mods.
James

kthiemann

Have you compared line pressure between auto and manual shifting? I wonder if maybe the manual shift valve in the valve body is sticking in the valve body.

DodgeFreak

I've checked the manually and automatically but never at WOT. I done it all up on jackstands so doing it at wot wasn't an option. Thanks for all your guy's help with some things to look at I should be able to figure it out. I even called my college instructor and he really didn't have anything either. THanks again if you think of anything else let me know. I would run pressure test right away but the trucks in Oklahoma and i'm in WI. I'm just tring to get things together for when i get a chance to work on it. That was the first shift kit i put in a truck also so i'm sure its some thing to do with that but i'm not sure.

jimbob1111

Hi
Nothing in the factory service manual on the flare at 2-3 WOT
It would be a good idea to call the Transgo folks and see what they say.

dozer12216

Believe your issue is with transgo kit engineering. Or four turns might be too much on pressure regulator. As you found out, more is not necessarilly better.
Now what's happening. On auto upshift the valves are timed hydrauliclly. As you move the manual valve this timing does not work. Tranny is actually dumping or releasing KD band before front clutch starts to apply. Did kit change operation of accumulator? did kit change the KD servo setup? Did kit change front clutch springs? Was the kit any more that another plate, a few springs and perhaps drilling a hole bigger? Is it possible some part was assembled wrong in VB?

DodgeFreak

It came with another plate it changed spring in the accumulator i believe. I know I replaced other springs in the valve body but i'd have to relook at the instructions which i have. Didn't change front clutch springs, and i went over the valve body and instructions about ten times to make sure it was assembled right as it was my first shift kit. Also, i got another shift kit from transgo for an older A518 trans in a 92 and it came with a resistor for the gov. Which the 518 isn't electronically govd. so could i install the resistor in the 98 and maybe cure some of the problem?? The other diesel trans i rebuilt in school had a 3 wire black box (can't remember what it was called) that i had to install in the wiring harness behind the air box. But the transgo resistor is for inline on the gov wire which i would have to look at again to tell you everything i have the instructions for every thing. except the the 3 wire one. Thanks for your help.

dozer12216

Resistor won't work on your unit.