I am having a problem with my transmission. When I put the car in reverse I can feel it engage and the car barely moves. When I give it gas it feels like the car is just free revving. I checked the valve body to make sure the O-ring for the low reverse brake was there and replaced it. I also inspected the valve body and everything looks fine. So after putting everything back together I tried reverse again and I had no luck. I decided to pressure test the transmission and I found that when the car is in reverse I am not getting any oil pressure in my low reverse brake. If anyone has any ideas of what could be going on please let me know.

Either the manual valve or you have something installed wrong in the valve body, that is if all other gears work and assuming that it all worked before you took it apart.

motomattx said:

Either the manual valve or you have something installed wrong in the valve body, that is if all other gears work and assuming that it all worked before you took it apart.

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Yes all the other gears work. You have any idea what valve it could be?

Possibly one of the two O-rings in the actual low/reverse brake piston, allowing fluid to get past it. In low "L" gear you should be developing around 50psi at that same test point, see what your getting. If its in the valve body you would need to be looking at the rear clutch exhaust valve, the 2-3/4-3 shift valve, the 1-2 shift valve, and the n-r control valve, those are all used to build that pressure for the low/reverse brake piston and kickdown servo. How far was the transmission apart? just the valve body?

motomattx said:

Possibly one of the two O-rings in the actual low/reverse brake piston, allowing fluid to get past it. In low "L" gear you should be developing around 50psi at that same test point, see what your getting. If its in the valve body you would need to be looking at the rear clutch exhaust valve, the 2-3/4-3 shift valve, the 1-2 shift valve, and the n-r control valve, those are all used to build that pressure for the low/reverse brake piston and kickdown servo. How far was the transmission apart? just the valve body?

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I will test it in L later today when I get home. Also I rebuilt the transmission and reverse was working fine but all of a sudden reverse and 3rd stopped working. When I inspected the valve body there was a spring missing in one of the valves so I saw a video that you just put in a steel ball since that valve isn’t suppose to move anyways and 3rd started working but no reverse. As for the valve body I just cleaned it but I didn’t take any of the valves or springs out. Is there anyway to check those 2 O-rings in the low/reverse brake piston without having to drop the Transmission? I remember when I rebuilt it I replaced them. I don’t see how they could of gone bad the transmission doesn’t even have 10 miles on it.

The only way to check the seals would be to dis-assemble the thing, the problem is that they might be torn or nicked even, who knows.

motomattx said:

The only way to check the seals would be to dis-assemble the thing, the problem is that they might be torn or nicked even, who knows.

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I saw an article here about lining up the oil passages and I don’t remember if I did that or not but according to the article this was a couple of people’s problem. I attached a file maybe this could be my problem. If I can’t figure it out I guess I’m going to have to drop the transmission to verify this.

Could be or the O-ring is missing or damaged.

@Bo0sTeD 4G63 what fixed your reverse problem? I just did an auto swap from a my 1g into my galant and I'm having the same issue with reverse. It clunks into reverse and will go, but it free revs when i give it gas. Reverse worked while the trans was still in my talon.

Could be low fluid, or clogged filter, the fluid is checked in neutral while running,

Thank you for the response. I guess I posted a little prematurely because with a little investigating I think I found the problem. My guess is the length of the 1g shifter cable coupled with the galant auto shifter was enough to not allow the trans to sit in the reverse position completely.

So what I did was I pulled the cable off the selector on the trans, started the car, pulled the ebrake and then went out and moved the selector to reverse. After doing that, i was able to drive the car in reverse just fine.

So to fix it, I modified the selector on the trans to allow for a slightly longer cable. This is probably not the best way to do it, but it appears to be working. I've attached some pictures of the modified selector.

motomattx said:

Could be or the O-ring is missing or damaged.

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Read this with interest since after having our ‘99 2G auto trans professionally rebuilt two years ago, it slowly started developing a hesitation to move in reverse when first starting up. If you wait about 45 seconds, then it will go, otherwise you need excessive throttle to move the car. Fluid level is full, and 6k on the rebuild so fluid and filter are fresh. All forward shifting behaves normally, although we do have to drive slowly for several blocks before accelerating onto the highway.
Motto - Does this sound like something that can be addressed without dropping the trans?

DogWhistle said:

Read this with interest since after having our ‘99 2G auto trans professionally rebuilt two years ago, it slowly started developing a hesitation to move in reverse when first starting up. If you wait about 45 seconds, then it will go, otherwise you need excessive throttle to move the car. Fluid level is full, and 6k on the rebuild so fluid and filter are fresh. All forward shifting behaves normally, although we do have to drive slowly for several blocks before accelerating onto the highway.
Motto - Does this sound like something that can be addressed without dropping the trans?

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If you go to a tool store like even the freight of the harbor and grab a transmission oil pressure gauge set, there are oil pressures that you can check with the transmission in the car to assist in diagnosing an internal leak like we are talking about, this can tell you alot before you go further into the transmission, say for instance all of your pressures are within the normal range, but the reverse pressure is off, then you know its not a pump or filter issue, its the reverse pressure from a torn seal or ring.

motomattx said:

If you go to a tool store like even the freight of the harbor and grab a transmission oil pressure gauge set, there are oil pressures that you can check with the transmission in the car to assist in diagnosing an internal leak like we are talking about, this can tell you alot before you go further into the transmission, say for instance all of your pressures are within the normal range, but the reverse pressure is off, then you know its not a pump or filter issue, its the reverse pressure from a torn seal or ring.

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Thanks! I will do that. Car won't be out of storage for a few weeks, but I'll report my findings.

Well I thought the problem was solved, but I was wrong. I figured out going from park to reverse is just fine, the car will go in reverse like normal. Going from drive to reverse causes the issue where it will start moving but if you give it any gas it pops out of reverse and free spins until the revs come down and it goes into reverse again very aggressively.

I put the ebrake on, took the shifter cable off the gear selector on the trans, put the selector from park to reverse and then hopped in the car and it drove fine. Then I pulled the ebrake and moved the selector to drive and then back to reverse, and then hopped in and the car did the free rev in reverse when I gave it any gas.

I'm not sure what the problem is, but at least its consistent and avoidable if I go to park before I go into reverse (which is typical).

DogWhistle said:

Read this with interest since after having our ‘99 2G auto trans professionally rebuilt two years ago, it slowly started developing a hesitation to move in reverse when first starting up. If you wait about 45 seconds, then it will go, otherwise you need excessive throttle to move the car. Fluid level is full, and 6k on the rebuild so fluid and filter are fresh. All forward shifting behaves normally, although we do have to drive slowly for several blocks before accelerating onto the highway.
Motto - Does this sound like something that can be addressed without dropping the trans?

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The O-ring that goes between the valve body and the case could definitely be one of the reason why the reverse is not working. If you check the oil pressure and its low I would next remove the transmission oil pan and check for that O-ring. While you are there I would also inspect the valve body to make sure its not clogged or dirty.

Devilsfutbol17 said:

Well I thought the problem was solved, but I was wrong. I figured out going from park to reverse is just fine, the car will go in reverse like normal. Going from drive to reverse causes the issue where it will start moving but if you give it any gas it pops out of reverse and free spins until the revs come down and it goes into reverse again very aggressively.

I put the ebrake on, took the shifter cable off the gear selector on the trans, put the selector from park to reverse and then hopped in the car and it drove fine. Then I pulled the ebrake and moved the selector to drive and then back to reverse, and then hopped in and the car did the free rev in reverse when I gave it any gas.

I'm not sure what the problem is, but at least its consistent and avoidable if I go to park before I go into reverse (which is typical).

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If you say it works normal from P-R but jumps out of gear or free spins from D-R I would say it has to be a valve body issue. If the gear is bad it would be bad completely so if it works like normal one way and not the other your issue should be at the valve body.

Your sure that your manual valve isn't broken in pieces right? this can happen when amateurs install the valve body.

I'm going to have to do some research because I don't know know what the manual valve is. I will say that before I grabbed this transmission out of my talon, I took it to a rally cross event and I dented this shit out of the trans pan and destroyed the magnets. There was a little bit of metal in the pan, but I didn't notice the trans behaving oddly. I put a new trans pan with magnets on when I pulled the trans to put it in my galant.

I haven't messed with the valve body at all because again I don't know how they work. I'll get a little educated on it and try to figure out how to check the oil pressure and check the o-ring between the valve body and the case.

Thank you for the responses, I'll see what I can figure out.