We have a 40 thousand mile original Mercury with the Merc O Matic auto trans. The trans shifts fine when in drive, reverse works fine. The problem is if put in low it locks up and will not move, and in park you cannot rev up the engine as it seems to be pulling against the torque converter. Anyone have any ideas of what is wrong with this transmission?
Can't help, but post this on The Ford Barn too in the "Late V8" section. All Ford/Merc stuff from that era.
What does the car do in neutral? Does it rev up like normal or want to move. If it does move, what direction. Bill
It revs in neutral, but may creep forward a little, I am not sure on the creep, and not with the car now.
That's a bit of a head scratcher. I can't think of any combination of clutches and bands used in normal operation that might cause that. In drive range you apply the front clutch and the front band, that's second gear. The front band releases and the rear clutch applies to give you high gear. In low you apply the front clutch and the rear band. Since you have to go through D to get to low, I suppose the front band might not be releasing. With three units applied, front clutch, front band and rear band, you would get a lockup condition. In park you have to go through reverse so if you apply the pawl, but the rear clutch and rear band were still applied it would load the engine. It sounds like your manual valve may not be moving correctly or the bore in the valve body is badly worn. It could be a problem with the internal linkage that moves the valve also. Years ago I was told about a problem with the manual valve on a Torqueflite that caused similar problem. The finger that indexes in a slot in the valve to move it was badly worn. This allowed the valve to be positioned a bit off and caused the transmission to try to be in two gears at once.
The early cast iron ford transmissions, if original should start out in 2nd gear and shift to third. Is it doing that? It starts out with the front clutch and intermediate band and then it goes to the front clutch and direct clutch for high. Reverse is rear clutch and low/rev band. Low is front clutch and low reverse band. What you are describing is almost hydraulically not possible. Elements are not in common. Bill
I had the valve body off of the car to replace the seals in the shift shaft which were leaking. But all of these problems were there before I did that. The valves that were moved by the linkage were all connected to the to the linkage correctly and moved correctly. This is a really nice original car with low miles.
I would try something different. Make sure car is in neutral with e brake on. Disconnect linkage from column. Start engine, then move (under the hood) linkage all the way down to get into Lo. Get into car, and with e brake released see if you still have lockup. This eliminates linkage issue. If still locked up, then the valve body may have a sticking front band apply valve. In that case the valve body will need to be cleaned. Another possibility is the front band servo gets applied while going thru drive and does not release as it should. This could also mean that the front band servo release valve in the valve body could be sticking too. I would take the car to a reputable transmission shop and have them clean the valve body first and see if that resolved the problem.
If you decide to take it to a reputable transmission shop, I wouldn't tell them what to do. I would have them diagnose your problem and tell you what repairs are needed.
I just found out that I assumed the old Ford-O-Matic, Merc-O-Matic was the same as the later Cruise-O-Matic, Mercury multi drive. While I have had a good number of the later 3 speeds apart, I hadn't actually disassembled the old 2 speed (I do have one in my T-Bird). I assumed the trans had 2 clutches, but it only has one. The trans input shaft is splined to the primary sun gear, so a clutch isn't needed. Your problem has to be the low band (not the reverse band) not releasing. It's a bit confusing to me as I would call that band the intermediate band since it controls 2nd gear. It is the front band inside the transmission. The first thing to try is a band adjustment. The adjusting screw is on the left side of the case, just above the manual linkage. Back off the lock nut at least 2 or three turns and turn the square adjusting screw in to a torque of 10 ft. lb. Now loosen the band adjusting screw exactly 2 full turns. Hold the adjusting screw in that position and secure the lock nut. If the problem was the band being too tight, that should fix your problem. Let us know how it goes.
Some of the old Motors Manual had an automatic transmission diagnosis section in them. I agree on a band not releasing. I'd tackle it myself before taking it to a shop, unless they have done old cars before.
Sage advice. One can pay extra to feel satisfied. I've had the misfortune working for opportunists (2) that made the customer feel smart. The second I had to change life. First time I just kept drunk. Once I went to THE National chain ( carry in )for a refresh on a known 3 speed stick. Curiosity lead me to crawl under another customer's car after hours the following evening. I was looking at my box. Day after I'm informed of the of parts that I was going to need. Best to have personal references.
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