In this post and another post I was asking for help tracking down a strange problem with 4thh gear. It was basically sliding into gear, and when throttle was applied it would slip for a second or two and then hold fast.

Well, after weeks of chasing this problem and worrying about it I finally found the solution. Last week I removed the valvebody and found that he plastic 4th gear accumulator had three big cracks in it, so I replaced it with a metal one. Unfortunately that didn't fix the problem.

Today I removed the servo cover and inspected the 4th gear servo assembly. Everything looked perfectly fine and the gold washer was in place, so I wasn't sure what to do. Before I removed the cover I remembered that one of the fine tranny builders here had said that the cover should only move in about the width of the snap ring. It seemed to me that my cover moved quite a bit more than that.

Wanting to at least try something. I found another washer half the thickness of the gold washer, bored out the ID of the washer to the correct size and installed both washers. Lo and behold 4th gear now hits just as hard as 2nd and 3rd with absolutely no slipping. Apparantly this tranny had enough miles on it that the band clearance had opened up and the Sonnax servo just didn't have enough travel to apply the band fully.

I just want to thank everyone who helped me out with this and answered my questions. Thanks!

Izzy

 

Well, after doing some digging around it looks like this checkball can be removed to speed up 4th gear apply. However, my tranny is still shifting very softly into 4th, as well as slipping for a second or two when throttle is applied. 2md gear is 110% fine.

I know the accumulator is good, so what else could it be? The servo cover is a billet Sonnax cover, so I'm assuming it has billet servos. Is it possible to have only a billet 2nd servo and stock 4th servo? Could it be that there's a crack or other problem with the 4th servo if it is stock?

 

The outter servo is the 4th servo. You could have to much clearance, or he gold washer that should be on the 4th servo could also be missing. I would remove the servo and inspect . When its out you should see a glad washer between it and the band pin this will either be stuck to the servo or on the pin, A qiuck but not acurate test for the band clearance is this use a pry bar and push in on the servo with the car off the servo cover should travel no more than the thickness of the snap ring that holds it in.

 

Awesome, thanks! This is exactly what I was looking for. I'll try the pry bar trick real quick and then probably disassemble it regardless and have a look. Does the servo cover o-ring always get destroyed(cut) when the cover is removed? I remember on one of my old 700-R4's I had to cut the o-ring to even get the cover off.

 

So be fore I tear this apart, does anyone know if I'll need a new seal for the cover?

 

just replace it as an good precaution.

 

I would, but if I can at least take it out and inspect the servo assembly I could do it now instead of waiting a week for the seals to get here, unless standard seals will work with the Sonnax parts???

 

One last try......is it possible to remove the servo cover without cutting the seal?

 

If you are carefull it is possible you have to work the cover out and yes the sonnax uses the standard oring for the cover.

 

Thank you so much! I'll put it up on the lift and check it out tomorrow morning.I'm guessing either the servo is cracked or the washer is missing. If not then I guess I'm outta luck because I don't know where else to look!