My '99 Ranger (3.0 V6) hesitates when shifting from R or P to D. It seems to take several seconds before I can feel it engage and sometimes, especially when the transmission is hot, it kinda lurches as it goes into D. It seems to work fine when shifting into R or if I start out in 1 or 2. There are no error codes, flashing O/D lights, or CEL lights. I recently bought this thing used and it appears that the transmission just had a fluid change. Where should I start? Could this just be a stuck valve, vacuum leak, or band adjustment? The fluid level was a bit high and I adjusted it and it now appears to be within the proper range. Could an incorrect idle speed cause this problem? The IAC was stuck and I cleaned it and it seems to be working fine now.
A low idle speed can cause this. Are U sure the IAC is now working? Have you checked it electrically? Does it maintain a steady idle speed as you add or remove load like headlights or a/c? If the IAC is working properly, you should find the change in idle speed as the load is changed or it is placed into gear to be almost undetectable beyond a momentary droop followed by an immediate return to the correct idle speed. If the IAC cannot do this, you need to correct whatever the problem may be before doing anything with the trans. The trans is electronically controlled with no use of vacuum. If it does not have a properly performing engine, you are likely to have symptoms show up in erratic trans operation.
Ok, thanks. I'll check the IAC some more but I thought it was supposed to increase the idle speed when such things as the A/C is turned on. I found some info on how to test the voltage of the throttle postition sensor but don't quite understand where to connect the voltmeter
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Maybe I'm just looking at it too early (before brain is fully functional) and it will be obvious when I get to it. So, there's no vacuum diphram on this trans? I don't even know the model number of the trans yet. Guess I better find out. In any case you have given me hope that it's not the transmission that's the problem.
I figured out how to check the voltage on the TPS and it was about .74 volts which seems to be within the correct range. There does not seem to be any adjustment on the TPS mounting screws. Am I supposed to adjust the throttle stop screw in order to change the voltage? This seems contrary to what I understand (or don't understand, as the case may be). The IAC is functioning properly as far as I can tell. I'm now thinking perhaps it needs a band adjustment on the transmission but I can't find all the information to do this. At the Ranger Station forum they have info on how many turns of the screws it needs but don't tell what to torque it down to first or which band is which. Hayne's manuals usually don't have this kind of auto trans info and I can't seem to find a Chilton. I also can't seem to find the Ford Service Manual on CD. There is some other manual available on eBay but the comments I've read sound like it probably won't have the info either.
First, the idle speed stop screw is adjusted by a particular procedure to obtain a specific idle speed with the IAC disconnected. This makes sure the engine will still idle and allow the IAC and the ECM to control the correct idle speed under normal operating conditions. The TPS voltage should also be within the correct range. Officially, the TPS is not adjustable as they once were. They do, however, usually have enough slack when you loosen the screws to allow for a minimal adjustment. If they are out of range, it would be recommended to correctly set the idle stop screw. Keep in mind that if it is set too low, the throttle may become a bit "sticky" coming off idle. Sorry, I do not have or know the exact procedure to correctly adjust the idle stop on your vehicle.
On the transmission, I do not believe it has any adjustable bands or anything else which could be adjusted externally. It has been several years since I had to deal with them. One thing I would recemmend if you are interested in learning more about the trans is to get a copy of the ATSG rebuild manual for your trans. They are very good about having exploded drawing, troubleshooting charts and detailed info on properly updating and repairing the transmission. Most parts outlets including NAPA, Autozone, Advance O'Reilly and the others should either have one or be able to get it. I would imagin Amazon would have tthem available.
Again, you need to make sure the engine is up to par before condemning the trans. If there is one near you, Autozone and some others will read any codes stored in the ECM on your '99 Ranger at no cost. Some problems do not become stored codes until the situation deteriorates enough. The equipment used by Ford dealers and many independant pro shops will be more capable of detecting those conditions. There are some engine problems that will result in trans problems. Any such codes should be corrected and the flags reset. The codes stored should include any fault codes set by the trans like slippage, high temp, etc. The last thing you want to do is start throwing parts at it until something works. A complete diagnostic scan is usually no greater expense than some of the sensors in the system.
Thanks for all the great advice. I read the codes with a CAN scanner and it showed no error codes. It sounds like I may need to take it to Ford (if they are still there) to have the TPS and idle stop screw adjusted/checked. I looked at the transmission and it appears that there is a band adjustment screw for D and OD and another one for what seems to be called Intermediate. According to what I've read R is not adjustable.
I'm not going to crawl under the truck and start turning screws until I've ruled out engine problems, like you said. It seems like it might be a band slipping in the trans but then I've never adjusted a transmission before. Just trying to get as much information as possible so when I get to the next step I'll be ready. Hopefully.
I did manage to get a difference of around 1/2 volt tweaking the TPS sensor while it was loose. Right now I have the throttle stop set where it's just not quite completely closed because I'd read about them sticking, just like you said.
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