Jeep Grand Cherokee tranny problems

[briansue]

I have a ?94 Jeep Grand Cherokee Limited w/ 5.2L V8 with what I believe is a 46RH transmission. Yesterday the Jeep would not start in Park. I fooled around with it for a while and it started in Neutral but would not start I Park. When I started to drive it would not upshift from Low. I could force it to shift if I let up on the gas pedal. If I pressed too hard on the pedal it would downshift to Low again. I can drive the car but I have to force each shift by letting up on the gas. I did not get a Check Engine light but I turned the key on and off and on and off a couple of times to get the diagnostic codes ? nothing showing there.

We live on a small island off the east coast of Puerto Rico. There are few mechanics here and they don?t seem to be very good mechanics. I took it to the only guy who works on transmissions. I explained what was happening. He did not check out the car or take it for a drive. He said there is a valve between the transmission cooler and the transmission that got stuck and the transmission overheated and burned up. He did not check the fluid but I did and it does not appear to be or smell like it is burned. He said the transmission needs to be rebuilt for $1,600.

On another car we had a similar problem a couple of years ago. Another mechanic checked it with a computer and said it was a module that communicates between the accelerator and the transmission. He cleaned the plug to that model and the car has worked fine ever since. I think maybe some sort of module or relay or plug or something in the linkage could be the problem with this Jeep. But I do not know where the modules are or what they look like or how to check them. ? Output Speed Sensor? ? Throttle Position Sensor? - MAP Sensor? - Powertrain Control Module? ? Transmission Control Module? Could it be one of these? How would I check to find out?

I do a lot of my own repairs because of the lack of mechanics here but I am not a mechanic. It is difficult to get parts here. Can anyone out there give me any ideas about what I can do to check out this transmission? Thanks for any help.

[Breaking it!]

First and fore most, change your filter and fluids in the transmission. Beyond that it probably is the Transmission Control Module. If you have access to a Haynes/Chiltons manual that would be your best bet for troubleshooting.

Hope this helps.

[jeepboy73]

sounds to me like a couple things. one, jeep has come out with a recall that pulls the shifter into park. over the years the shifter becomes sloppy and it is likely that the car could not be in park and roll down a hill or something. this fix is easy, there is a nut where the cable linkage bolts to the trans that comes loose, tighten it. two, sounds to me like you have a internal seal problem. i worked at a jeep dealer and you wouldnt believe how many times ive seen this problem. it is especially common in winter time. in other words bebuild time. if money is tight i would take breakin it's advice and change fluid and filter to try to nurse er along. also check out http://www.phoenixhardparts.com/ i think their prices are reasonable. good luck.

[briansue]

Thanks for all your help. I believe this transmission is a 46RH which is what the book says should be in this car. As far as I can tell there is no Output Speed Sensor on this transmission - I can't find one and they don't show one in the parts manual. The car will start sometimes when it is in park but not every time. It will always start in Neutral no problem. I have tried the codes and get nothing. The light does light and blinks to say it has checked the codes. I am not sure how to adjust cables or how that would affect shifting. The vehicle is driveable but I have to force it to shift by letting off the pedal. If I apply too much pressure it will downshift again. I checked the fluid and it appears clean and not burned. Fluid and filter were changed in the last year. Still looks fine. The transmission does not slip and pulls strong. Someone suggested the Throttle Position Sensor but I am not sure what that does. I was able to find it and know where it is but I don't know what it does. I think I know where the Transmission Control Module is but not sure if I can get one in PR. Is this a common Jeep part? How much do they cost? Western Auto (still called Western here) shows the TPS for about $12 but not the TCM. Maybe I can order one shipped by Jeep? There is a cable that goes from the throttle linkage to what appears to be some sort of vacuum can mounted on the fender well - this cable appears to be slack. Other cables appear to be OK but I am not sure what they all do or how to adjust - or how they should be adjusted. The cable that attaches to the transmission is secure and the detents seem OK. This car has the towing package so it has the large trans cooler. I don't know how to check pressure and probably don't have the tools to do this. On this small island the car rarely gets driven more than 3 or 4 miles at a time. Would that be enough for it to heat up and burn the transmission? It has been used to tow a boat but not for several months before this problem showed up. The mechanic who said the transmission needs to be rebuilt did not even ask what year it was or check to see which transmission it was. He never drove the car or saw it driven and he never looked under the hood. Maybe he really knows what he is talking about but I just have a hard time believing him. To get to the nearest Jeep dealer I would have to take a ferry. It takes about a month to get a reservation on the ferry. It is very difficult to get things like this done here. But we never have winter here. 80 degrees all year round. Almost never below 70 or over 90. I have the Haynes manual. Getting a rebuilt transmission shipped here could cost a fortune. Transportation is a serious problem here. Thanks for any help.

[jeepboy73]

just wondering, did the trans all of a sudden start acting up, or has it been getting worse over time? is the trans worse when cold and better when warm? seriously. the bracket on the trans where the cable goes to the valvebody lever loosens up and has to be retightened, ive seen this many times is why shifter get loose. its kind of hard to get to. i used to work at a jeep dealership untill the franchise was sold. when its gets cold up here in michigan, we would see it all the time that the 46rh, 44rh, and 42 rh would have a problem when cold, that the trans would't up shift untill you let off the gas, and gets better when warm, but gets progressively worse over time. your valve body is what controls hydraulic pressure, there could be a problem inside with a shift valve or something, but ive never seen a problem like that, nor have i seen a problem with tcm's.