Hi,
'00 Camry LE 4 cylinder, auto tranny at 120K miles. Just lost the reverse gear all of a sudden. It has been “jerky” in reverse a couple of times when going up the driveway but no other symptoms before it suddenly stopped working.
It feels like it shifts into gear but the torque is not transferred to the wheels - the enigne revs-up but the car does not move.
Forward gears work well as do the interlock switch and it seems - the park/neutral switch (I tried agjusting it but no effect).
I have removed the valve cover only to find that there are virtually no metal shavings (only a little fine dust on the magnets) and no sludge. The strainer filter is also clean with pretty much no particles inside it.
I tested the two solenoids on the valve body and they measure about 12 ohms each, which I think is OK.
The fluid is the correct type (Dexron III) and has been at level always (no leaks, flushed twice so far and always refilled with synthetic fluid).
Is there anything else I can check before going for a replacement transmission? I do have the service manuals for the car but am not a mechanic and they ommit a lot of information…
Any hints would be appreciated! Thanks!
The problem might be due to a failed O-rings on the spool valve in the valve body.
When you shift gears, the spool valve moves along it’s bore to direct hydraulic pressure to the clutches for that gear. The spool valve has a series of O-rings that seal between the ports for each gear. In your case, the O-rings that seal for reverse may be leaking. Thereby, not enough hydraulic pressure is produced to engage the clutches for reverse.
Tester
Or, install a circular driveway.
Thanks for the suggestion. Not sure what the term for a “spool valve” would be in Toyota-talk (the repair gides do not mention such a thing). There is a manual valve body that is driven by the manual shift lever - I removed that but it is a simple device with no O-rings inside and looks fine. I have a used transmission at hand - will replace my valve body with its valve body as a last attempt at fixing my transmission on the car. If that helps, then the problem would definitely be in the valve body and that can be repaired relatively easy I think. If not - out goes the old tranny along with $400 labor charges as I’m not sure I can do it myself, and in goes the new one…
Or, install a circular driveway.
Or just use an inclined drive.. :-)Swapped the valve bodies - no change. The reverse gear is still not working.
If you have any other thoughts on things to check - let me know. Now I need to decide if I can tackle the tranny swap myself or would need to fork-out another $400-500 for labor and the few small parts that need to be replaced when installing a new transmission…
Thanks!
If you are able to remove the valve body, you are probably capable of checking the status of the clutches. Find the passages for the high clutch, the reverse/low clutch, and the direct locking clutch in the overdrive gear set. Check each one for engagement and air leakage – I think it was 50 psi for less than 10 seconds. If you hear air leaking from any of the clutch pistons, you have an internal problem. I am assuming you have a solid third gear; can get the engine braking with OD button ‘off’; and get engine braking in manual 1st gear. Finally put a pressure gauge on line pressure tap and see what you get when you go into reverse. The service manual should give you the idle and full throttle pressures for reverse. If the pressures are nonexistent or low, you probably have an internal seal problem or a pump problem. Also check the pressure in forward gears sitting and driving to see if other clutch hydraulic problems exist. These diagnostic steps should narrow down the problem. If you do find out the exact failure (tear the transmission down and inspect all the clutch piston seals, the slip rings, the clutch frictions and steels, and the pump), let us know for our information.
I think what he is talking about is the manual valve. This is a steel valve which is directly connected to the shift linkages. This valve directs the fluid through the valve body and the worm tracks in the transmission case to apply clutches and bands. I dont know of any valves in an automatic transmission which have 'o’rings on them. There are ‘o’ rings on shift solenoids and pressure control solenoids. I wouldnt bother playing around with the valve body any more and as far as the shift solenoids go, leave them too since reverse is not controlled by solenoids or even by the computer. Reverse gear is simple to diagnose since there is not much involved in its operation. If you have lost reverse in any automatic, unless you are low on fluid or your linkages are not right, you can count on removing and disassembling the transmission for internal repair. In your case, you probably have lost the reverse clutch. There is no need to remove the valve body again and try air checks. This trans sounds like it needs to come out. Let us know what else you find out.
transman
I did in fact replace the manual and the automatic valve bodies in my transmission with the units from the replacement transmission as I said in my other post. And you are rignt apparently - still no reverse gear.
I will be replacing them back into the “new” transmission then will take the old tranny out when I get the chance. Need to first find a suitable (read: cheap and used) transmission jack or engine hoist to help with this - the transmission is quite heavy and I do not see a safe way to do it without at least one of these tools.
Will definitely let you know what happens once I have more information.
I am not sure if I will be doing any further diagnostics though after I replace the transmission, especially if the new one works. I have to return the old “core” to the junk yard in a couple of weeks in order to keep my 100 days warranty, though I think I might as well keep it and forfeit the warranty if I figure out how to fix my old tranny and re-sell it to off-set my cost.
Thanks for the suggestions! I finished the installation of a “new” transmission off a '01 junked Camry with low miles. Worked great and the car is as good as new now. Unfortunately, due to lack of time and experience I was not able to diagnose what was wrong with the old transmission. All I can say is that whoever said it was a hardware problem was right and the new transmission resolved it.
I have a brief write-up on my transmission replacement job here if you care to look: http://www.pbase.com/kocho/camry
Regards,
Kocho