nxk2000

I think I'm a bit far from home here working on a 1997 Astro van but all of my searching was bringing me to this forum. So I thought someone might be willing offer some help.

My 4l60e lost 3rd so over the holiday I decided to go through it myself. I found the cause of the problem was the input shaft and mating stator were badly worn. I visited a local trany shop that helped me out with parts. I got a used input housing and they pressed a used stator into the pump cover. They did not have a refurbished pump cover but did have a body ready so I picked it up as well.

I have it back in the van but as you could probably guess something isn't right. On light acceleration it seems to shift ok but any more and you get a slight flare up on 1-2 shift. 2-3 flare up is much worse and you have to let off the gas for it to catch on heavy acceleration. It only acts normal once it locks up. I hooked up a pressure gauge and get 70 in D and 90 in reverse. I drove it with the gauge hooked up and the highest pressure was 110 when I floored it from a stop. I noticed a few times the gauge would start jumping up and down about 10psi. This was just around the block. Didn't want to drive it to much.

I'm thinking the shift flare might be caused by low pressure. With my pump being the start of the 13 vane pump would a older body mixed with my cover cause low pressure? I would hope the guy at the shop new what he was giving me. I have read that the sonnax boost valve might help my issue.

I would greatly appreciate any help to get me going.

Thank you

carlsonauto

I dont believe your issue has anything to do with a boost valve. You almost certainly have a pump issue. There are different pumps and if they are mismatched they can cause issues but I'm not so sure that is your issue. My gut feeling is that you didnt put the plastic filter into the pump body. It slides into the pump from the od of the pump body and has an o-ring on it. It's a black or white screen that resembles an hourglass and is roughly 5/8" in diameter and 1-1/2" long. Without that screen it bleeds the line pressure off and line pressure readings do exactly what you have explained.. Dont ask me how I know this :-)

nxk2000

I did replace the filter screen. So I'm pretty certain it's in there.

I'm think no matter what I probably should go ahead and start pulling the transmission back out.

carlsonauto

If you still have the gauge hooked up try unplugging the electrical connector and start it. the line should max out. If it does the issue is electrical if not its mechanical. Im guessing its mechanical but who knows, its easy enough to check.

nxk2000

I disconnected the plug. Pressure seem to slowly climb to 180 then dropped to 120. From there it was Jumping 120 to 150. Higher then before but should it be jumping?

carlsonauto

No it should not be jumping all over the place like that it should be fairly steady. It would seem that you have a fluid leak somewhere, either on the suction side of the pump or on the pressure side. Not much there on the suction side to go wrong as its a pretty straightforward deal as the filter inserts directly into the pump. There could be issues with the valve body as well as the pump but since the pump was replaced and possibly mismatched that is personally where I would start looking. Others may have other ideas but thats my .02

carlsonauto

also the screen that I was questioning earlier is the one to the far left in this guys pictures just so we ase both on the same page on that.

http://www.ebay.com/itm/4L60E-4L65E-...5d4148&vxp=mtr

nxk2000

Thanks for the info. I agree that the issue is in the pump. I think I'll give it a break for a few days and like you said see if anyone else has any info as well. I will give the shop a call and see if I can get my old pump body back. I probably should have stuck with my original pump body. The guy said it wasn't really that bad on the wear. I just figured he was doing a few extra things to help me out so if I spent a few extra $$ it wouldn't hurt anything. Didn't realize his extra help may be whats setting me back.

mrvedit

I have checked max line pressure on the few transmissions I have built and they all held a very steady pressure. (About 225 psi with boost valve.)

Carsonauto is way more experienced then me, and his comments all sound correct. I think it it just bad luck, either the pump was more worn then expected, installing the stator shaft bent the case a bit, or in a rush it was not assembled right. I would check for the O-ring under the pump slide if it is ever opened up again. Also that that the boost valve and pressure regulator valve are assembled correctly.

A Sonnax boost valve might still be a good idea as it includes O-rings to account for any bore wear. I have no idea if excessive bore wear could cause this problem. At least it can be installed without dropping the trans.

nxk2000

I stumbled across the problem tonight. The filter had a crack in it. Now that I have seen it, it seems a bit obvious. Something I should of found on initial assembly. I just hope I didn't cause to much damage to while trying to figure it out. I replaced the filter and everything is much better except 1-2 shift. It seems to hold first a little long then you get a 1 second pause and slam. Does the 1-2 accumulator affect when it shifts or just the firmness of the shift?

I ordered all the parts from Oregon Performance Transmission. That box was packed really tight. I can understand the filter getting broke if the box was thrown around.

mrvedit

Glad to hear that you figured out the main problem and that it was a simple fix.

Only the PCM via the Shift solenoids determine when the trans shifts, but the line pressure, separator hole size and accumulator springs determine how long the shift actually takes and how it feels.
For the 1-2 shift the hydraulic fluid has to fill the 1-2 accumulator and move the 2nd-apply piston in the servo and band before the shift is complete. Any type of problem or leak in the accumulator or servo, or a too-loose or too-tight band could dramatically slow the shift and/or make it slam.

I don't have the experience to suggest whether your problem is more likely the accumulator, servo or band. Fortunately these can all be checked and likely corrected without removing the trans.

You probably already know that the 1-2 accumulator can easily be checked - you only have to drop the pan and remove its three bolts. There are numerous reports of broken springs and cracked plastic pistons causing problems. An aluminum piston is a suggested $2 upgrade.

Perhaps someone more experienced can give you more specific guidance.

carlsonauto

As long as the plastic accumulator piston was replaced with an aluminum one and it was all assembled correctly I would look at the servo first.. Or just look at the servo first anyhow because its easiest...

Easiest thing that I would do first is pry in on the servo cover and see how much travel it has before it bottoms out. That will tell you a lot about how far the servo has to move to before it applies the band. If it moves more than 1/8" its too much If it moves a lot more than 1/8" its most likely the issue.

Wether it burnt up the band or not is another question all together. If it only moves 1/8" or a little less then its good as far as band clearance but there very well could still be an issue with the servo and its easy enough to take out in the vehicle. Especially in an astro van, There is almost enough room to throw a party under one of those compared to most vehicles... I have put servos together before and had the scarf cut sealing ring on the O/D of the 2nd piston pop off and I never knew it until second gear didnt work so good.

nxk2000

This one has the original metal piston. A couple of years ago I lost lock up on the way home from a trip. A shop told me to put a trans go kit in that included a new valve to correct the bad valve body. Said he normally only uses the valve and throws out all the springs that came with it. I went ahead and put in what springs I could. Didn't notice a difference with anything other then lock up worked. I'm pretty sure I installed a spring in the 1-2 accumulator. I thought I would return it to factory but not for sure what springs are factory. I have been using Alldata for the repairs but it's showing a older design then what I have. I have 3 springs in mine and couldn't find the trans go instructions to see which one was added.

The band seemed to have a bit more then 1/8 of movement. In the left over parts that I still had from that trans go kit was a gold ring that I believe is used to take up some of the play. Should I use that ring or try a longer pin?

mrvedit

The Transgo HD2 kit instructions are here:
https://ls1tech.com/forums/automatic...questions.html

If you are not sure what springs you have in the 1-2 accumulator, I would start with the two stock ones. I could send you a pair if you cannot locate them. Was the Transgo Boost valve installed? Was the separator plate drilled to the Transgo instructions? All these things work together to give proper shift feel; i.e. installing half the kit might give you strange feeling shifts.

Yes, you can install the Transgo gold rings to tighten up the servo. See the Transgo instructions in the link above.

08GXPLS4

Make sure you installed the correct Pin sized accumulator, also check your basic line pressure readings, servo after that i would check and see if the 1-2 accumulator valve is sticking in the bushing in the valve body

nxk2000

As far as the springs go I didn't change anything from what I did 30,000 miles ago with the trans go kit. After I did it then I didn't notice any real difference. I did replace the plate and from what I remember the plate was a trans go and it was drilled already. The instructions that you linked to look a bit different then what I had. I know it didn't come with a boost valve and it only had one of the gold rings. It also didn't have the washers that went in the bottom of the accumulator bore.

http://www.tonkinonlineparts.com/sho...ssembly=839050
The springs I have are like this picture 54A and 54B but I have 2 of the 54A but one fits inside of the other and 1 of the 54B. I figured I would try pulling out one of them just didn't know which or if it even matters which.

mrvedit

I cannot image how you could fit two of the stock outer springs (54A) into the accumulator. In any case you want to check that first; as you know, you only have to drop the pan and remove the three accumulator bolts to drop it. Also check that the gasket is not damaged under it. And of course the pin and piston as suggested.

As 08GXPLS4 suggests, the accumulator valve (actually regulates both 1-2 and 3-4 accumulators) can stick in its bushing (sleeve) after many miles and affect the shift feel. The valve body needs to be removed to check it. (I'll admit that I once installed the bushing up-side-down and it still shifted just fine.)

It does also seems likely that your band has worn down, making the servo pin loose. Perhaps tightening that up with one or two Transgo rings will give your trans more life.