MikeyZ

iTrader: (20)

well I rebuilt my 4l60e with a transgo shift kit, sonnex sunshell and it went together pretty smooth however I have no reverse and laxed shifting... any ideas for me? I know the teflon rings are a culprit how ever they went into the pump so easy I cant see ripping them..


I also have all forward gears and low engine braking.

MikeyZ

iTrader: (20)

well I found if I raise the rpms to 2500ish I have reverse. any Ideas?

MikeyZ

iTrader: (20)

any Ideas anybody?

mrvedit

It sounds like you have a significant leak and will have to pull the trans and rebuild the reverse drum. Here is what to check and watch out for:

1. Check if one of the teflon rings on the pump stator shaft got damaged. You should leave a resizing tool on the rings until the minute you install the pump into the reverse drum. I had a trans shop install the rings and I keep them snug with the plastic from a cut up 2L pop bottle and two hose clamps. (Not too tight.)

2. Next, check the inside of the reverse drum where the teflon rings ride and make sure it is absolutely smooth. If rough, get a new reverse drum and install new teflon rings.

3. Else disassemble your reverse drum.
A - Make sure you didn't cut either seal for the reverse piston. This piston is hard to get in as it has two seals. A "Transtec Lip Wizard" is useful for this and should be free from any trans shop. First make sure the inner seal is past the lip and then work on the outer seal.
B - Make sure you installed the Belleville plate correctly; (concave side down into drum).

4. Air check the reverse drum with a rubber tipped blow gun. This is kinda hard to test as the access hole is hard to reach and has a square shape; also the piston has a vent hole and will appear to leak. Personally, I check it after only installing the piston; I plug the vent hole with my finger, apply just a little air pressure to verify that the seals are not leaking while also holding the piston down.

I'm no trans expert, so watch for any corrections/additions to this info.

MikeyZ

iTrader: (20)

I installed the rings and they went in so smoothly so I dont think thats the problem... I also air checked the reverse drum with air and it checked out...

mrvedit

Did you check the ring surface on the inside of the reverse drum?
Fortunately the trans shop that installed my rings asked me to check it and mine was bad. (It was also a trans I bought off CL with no reverse.)
Otherwise, the air check would go fine, but the rings would wear very quickly.

The hydraulic fluid for reverse comes directly from the manual valve. There is a "Reverse Abuse Valve" which: "provides a faster apply of the reverse input clutch when throttle position is greater than idle. During these conditions reverse fluid pressure increases and moves the valve against spring force. Reverse fluid can then quickly fill the reverse input fluid circuit. This bypasses the control of the reverse input orifice for a faster clutch apply." (From the GM 4L60-E Technician's Guide.)

The fluid for the reverse clutch goes past the boost valve and past a check ball (I think in the pump) before going to the stator shaft.
An upside down boost valve might prevent reverse.

I'll photo and post the hydraulic circuit for reverse if you want.

Since you had to separate the pump from the reverse drum after your air test for final assembly, the teflon rings are probably still the most likely trouble spot.

Perhaps a trans expert has more ideas.

MikeyZ

iTrader: (20)

Well I put a pressure guage on it and here are my readings

reverse is 50
park was 110
1 and second bounced between 200 and 225

these were taken with the connector off and at 1000rpms

any ideas?

mrvedit

I just bought my own pressure gauge and plan to test my working transmission this weekend. (Before I swap in one of my rebuilt ones.)
So, I have no experience, but here is what I have read:

Typical pressure in Park is around 90 lbs; pressure in Reverse is around 150 lbs. The reverse hydraulic line runs into the boost valve in order to increase pressure. (That's why some call it the Reverse Boost Valve.)

My guess: you either have a large reverse line leak, or perhaps you installed the boost valve incorrectly.

Hopefully a more experience person will chime in here.