I just finished installing my newly rebuilt A518 automatic transmission into the 93' on Tuesday. The transmission builder did an awesome job and everything looked great! My first test drive proved to be a real downer............

Immediately after taking off for the first time the transmission shifted from 1st to 2nd almost instantly, then 2nd to 3rd followed just mere seconds later. Huh??? Just to review, a local 1st gen guru had adjusted my valve body several months before the rebuild to have the shifts far apart. I loved the way it shifted after this person worked his magic on the valve body. Now after this transmission rebuild, the truck shifts very quickly (not enough time to build speed/power between gears). I can almost count to 5 seconds from taking off and its already into third gear!!!! Yikes. The transmission builder was briefed in detail about the transgo shift kit already installed. The biggest and worst issues is this: The truck falls on its face and will not build boost above 10psi ***????? I can put the pedal to the floor while driving and the truck will not downshift or speed up, it just drives around the 5-7psi range. Its down right scary climbing a hill..........the truck slows down and barely climbs the slightest grade!!!!

Things I already checked:

-no transmission leaks, and the fluid is at the correct level
- all intercooler boots are intact and not leaking
- throttle lever is getting full travel on the injection pump
- all cables associated with the transmission are adjusted equal to my friend's 1st gen (runs & drives awesome)
- throttle responds correctly in Park or Neutral

I am really bummed about this, especially after spending some good $$$ and plenty of my personal time to get this transmission project to where it is now. I have had to cancel numerous road trips and camping events due to my truck problems. It almost seems like the engine is not getting enough fuel, therefore my boost pressure is extremely limited. Would a worn lift pump cause this? I would appreciate any help or advice on this matter.

 

Unless there's more to this story, (like you pulled other things apart on the motor while doing the tranny install), it sounds like the the tranny is holding back the motor, not allowing it to rev.

I don't understand a few things here tho; why don't you call the tranny rebuilder and ask about adjustment procedures? I am assuming he's too far away to drive there. If you can't do the adjustments yourself, what about the guy that adjusted your shift points, can he help you?

I think I'd get the tranny straightened out before I messed with the motor.

chaikwa.

 

I'm like chaikwa not understanding a few things or you left some things out. Let's start at the beginning. Did the truck run good other than the trans having problems before the trans rebuild? Have you done anything to the engine at all before it started running bad? Did you just swap out the trans and not do anything to the engine? If any of the above is no call the rebuilder of the trans or the friend who made it better prior to the rebuild. If any of the above on the engine is yes what did you do to it? Give us a good answer on this and we might be able to figure out your problem. Sorry to hear your having problems and good luck with it.

 

is the TV cable adjusted right? try making it tighter and see if it changes things.

 

Sounds like the TV cable is binding up and not allowing the RPM"s to go up?????? you said it revs normal in park and Neutral ?

The problem with the quick shifting sounds like TV cable is adjusted wrong or something internal in the valve body. I think you're having the opposite problem "The_Head" is having with his built 518

 

I'm with the rest of the boys, sounds like the TV cable needs adjusting.

 

also make sure the return spring is on tv cable and working properly

 

The TV cable may be the problem but that wouldn't keep boost at those low levels, would it? What about egt's and how much smoke are you getting? If you are dumping fuel and the engine is bogging down because of load, I would expect to see lots of smoke and heat. If not, there could be a another issue.

 

if there is no load on the engine then yes the boost numbers would be low. Boost is dependent upon load on the engine.

 

x2, if you shift the auto manual while flooring it you'll see the boost go up with every shift..

 

Ok guys here's the scoop:

1. Transmission was all stock several months ago and installed a Hughes converter and Transgo shift kit

2. 2 weeks later I pulled my new 23ft 5th wheeler for the first time since installing my converter/shift kit. Transmission overheated severly on this trip and temps flashed once to 250 degrees on the tranny gauge. I lost overdrive completely and limped the truck home.

3. After this trip the transmission seemed slopping and the shifting was poor

4. Truck sat for several months with occasional low mile local trips

5. Pulled transmission last week and decided to get it fully rebuilt, found out that all forward clutches were pretty much gone and the overdrive was completely gone. The fluid was burned horribly too. Valve body with Transgo shift kit was re-used during the rebuild.

6. Got new transmission back and installed........this leads me up to the current thread topic.

 

were the trans cooler lines flushed well before being reinstalled?

 

Yes, I flushed the lines repeatedly. I also used a magnet to see if I could pick out any pieces from the fluid. I didn't get much of anything.

 

what kind of converter do you have. and after the over heat it should be replaced the do you know if it was locking up. the trans require converter lockup to help cool it especially in OD. if you dont have this it will kill the trans.

 

a 518 is a non lockup trans.