4L60E Transmission problems
You need to get a pressure gauge on that thing asap. After that tell us the pressure readings in reverse, neutral and in drive. Look for pressures anywhere from 75 psi to 175 psi depending on throttle pressure. Snap the throttle to WOT in neutral or park you should see a rapid increase in pressure. Pressure will read higher in reverse depending on throttle position. You will need a gauge that is capable of reading up to 250 PSI. There is only one pressure tap on the unit... drivers side a few inches above the linkage.
Also, do not drive the car on the street. If it is slipping you will be damaging soft parts and can be losing lube pressure to hard parts which will cause them to fail prematurely. Pick the rear wheels up onto jackstands and then run it... take the load off of the tranny while running it until you figure out the problem.
The sealing rings on the input shaft can be tricky to install if you do not have the correct tools. Did you remove and replace all of the pistons / piston seals and shaft seals in the input assy?
Don't be discouraged, building automatics is not easy.
g
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Thanks for all the great response that i got. I was alittle brief on my first post i was not sure what kind of repsonce that i would get. I did some checking and will explain more. I have 70+ psi in park and goes up 200+ on rev up of motor. 80+ in reverse. When the truck is put in drive you can feel what i believe is the piston engaging, but when you hit the gas the clutch just slips it will not move the truck. It does the same in 3rd, Now 2nd will move the truck some but barely. When pulled all the way down to first gear it will move the truck aroud. When you gas it hard it will slip. So if it half *** locks up when you pull it down in 1st. Why dosent it do the same when you put it in Drive, because it still starts out in first gear.I did air check all the pistons and they seemed fine at assembly. clearence on clutch plates all checked ok Too.
Here are some basics...
In order to achieve reverse... L/R clutch and Reverse Input are applied. That rules out those clutches and related seals as you stated that R is good.
In order to achieve manual 1st... the overrun clutch, forward clutch, L/R clutch, low sprag and forward or input sprag are applied.
In 2nd all that happens is L/R clutch is released and the band is applied holding the reverse input drum.
And for 3rd the band is released and the 3/4 clutch is applied.
We can say that the L/R clutch is good, the Reverse Input is good and it appears to have gear changes.
Based on that info it seems to me the suspect components would be the forward clutch and the Low Sprag. The easiest place to start would be the accumulators, a pressure loss there will cause all sorts of similar symptoms.
What was the original failure that led to the overhaul in the 1st place? There might be a clue for you there.
g
Last edited by Gilbert@Ace Racing; Jan 19, 2007 at 09:34 PM.
No the truck would not move in Drive or Overdrive when i had it together. I am thinking that it is the imput drive, so i have pulled it back out to recheck everything.
I pulled the pump and ready to start the recheck. Mark C
The shaft seals could easily have been the reason you lost 3rd to begin with. Take the time to find the correct installation tool, especially if you plan on doing another one in the future, when you get the tool install the sealing rings... takng shortcuts inside automatic transmissions is not smart. Regardless of how those seal looked! Trust me when I say the car gods do not reward shorcuts with good performance.
Using the scarf cut seals is not a good idea.It can be done of it is the last resort. But why do it if you can take the input assembly to a tranny shop or dealership and for a few bucks they can install the seals?
Before you completely dissasemble the input assy... support the pump with a coffee can or something similar.... then install the input assy inscluding the reverse input drum... then use a rubber tipped air nozzle to check the engagement of the pistons by applying air pressure to the pump pressure ports. Do this to each and every unit you have a part in order to build good habits and in order to check your work prior to final assembly.
Keep us posted! Feel free to pm me for tips or advice.
g
The input housing looks good, i have gone over it again too. Thats it for now i will post more when i get more work done on it been busy. Mark C
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