98LS1driver

iTrader: (2)

i bought a built 4l60e from a friend that has a problem. i installed it in one of my previous cars and it has 123 no problem just no lockup or od it has a billet servo on the side of it and i have had one before do the same with the billet type servo and i swapped it to a stock one and voila it worked. What or how do i setup the billet one? ive built a few trans 4l60e's but always went with stock servos

mrvedit

So you have no 4th gear; since lockup generally only occurs in 4th gear, I wouldn't worry about lockup until all gears work.

I would first scan for any codes; some codes do not immediately cause a MIL ("check-engine light"). While a code is not very likely to cause your problem (no 4th), checking this is a lot easier than removing the servo, which can be very difficult in some cars.

Just underneath the servo cover is the 4th gear apply piston. Sounds like something is wrong here. First check that the piston seal is there and in good condition. You might even pull the rest of the servo out and check that this piston seals well in the bore as you move it in and out.

If that looks OK, can you determine who made the billet servo? It could be Superior, Fairbanks or Sonnax or perhaps others. Is there a name on the cover? Perhaps you could post a picture of the servo parts.

Just a guess, but the servo pin might be too short. Can you estimate how much the servo cover will push in (with perhaps 100lbs of push) from its sitting position? 1/16" to 1/8" is normal; anything more indicates the pin might be too short.

Here are the Sonnax instruction for their 2nd and 4th gear servos:

http://www.sonnax.com/system/instruc...911-03K-IN.pdf
http://www.sonnax.com/system/instructions/77767K-IN.pdf

Note the instructions on how to test the pin length.

98LS1driver

iTrader: (2)

i will post a pic of it when i get back in the shop the cover has no name on it at all and when i pushed it in im pretty sure it went in more than 1/16 to 1/8th inch and the trans is going in a ls swapp car so i can scan for codes until i get it in car lol. thanks for the advice i will let you know asap on it!!

mrvedit

OK. Try to measure how much the cover will push in. A dial indicator would be perfect, but of course won't stick to an aluminum case. Or just hold a ruler next to it as you push it in. Its starting to sound like the pin to too short.

98LS1driver

iTrader: (2)

Finally measured it I got a fully out measurement to 1 11/16 and pushed in fully 1 1/2 what do u think

mrvedit

That is 3/16" difference or .188 which is .060 more than recommended. Sorry, but I just don't have the experience to be sure this is your problem.

Interesting, I just helped someone else who had 4th gear but no 2nd gear. On my recommendation he lengthened the pin by .100" and got 2nd gear back. In his case the excessive clearance due to a worn band caused him to lose 2nd gear before 4th gear, which is the opposite of you. However you have a billet 4th piston which changes things quite a bit. Here is that thread:

https://ls1tech.com/forums/automatic...-gear-all.html

Perhaps one of the pro builders can confirm whether your pin is too short.

carlsonauto

While .188 is too much pin clearance/travel it should not be too much to the point of losing gears. There has to be an aweful lot before it becomes enough to lose gears totally. Too much pin clearance/travel will just make sloppy sluggish shifts unless it gets pretty extreme. That doesnt mean that whatever aftermarket servo it has still doesnt have an issue though.

98LS1driver

iTrader: (2)

so can i buy one from the dealer already set right or will i need to set it as well? or just buy a new pin and set it

mrvedit

CarsonAuto doesn't think your .188 clearance is too much to lose a gear, but hard to be sure with a billet 4th piston. A leak in the 3-4 accumulator (under the separator plate) can also cause weak/lost 4th gear.

A standard length pin works fine with new stock parts. Not sure if GM makes a longer pin, but other sources definitely do. Those pins tend to be quite a bit too long and are designed to be ground down to the needed length.

Sorry, but I just don't have enough experience to give you a "for sure" solution. I was helping someone a few months ago with a similar problem that his local trans shop was having trouble with. After checking the servo and replacing the 3-4 accumulator they finally replaced the valve body to solve the 4th gear problem.

In another recent thread the OP had 4th but not 2nd and we determined is a worn band. He welded a .100 blob on the end of the pin, ground it down and got all his gears back. That indicates that a worn band might cause 2nd to be lost before 4th, but again your billet 4th changes the equation.

If your servo is easy to remove, you might also consider putting a "pin extender" on the pin for testing purposes. Or if you can weld, weld a .100 blob on the end.

Do you have any idea when/if the trans was rebuild and how many miles might be on the band?