Damn it. I was hoping you nailed it!
‘99 Highway RPM range (4 Viewers)
- Thread starter 900exdriver
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Wanted to add some info on driving at highway speed and letting off the gas pedal since you asked. I was out and got the rig up to 62 mph or so and let off, rpm's stayed around 2k. Only dropped a couple hundred rpms. Hope you figure it out.
Does the light being burned out mean something? This is sounding stupid just typing but mine is out and I am at around 3,000 at 70 too. Never thought much of it since I don't do much highway driving- Im in school
- Thread starter
- #44
Thank you. That makes it sound like I’m not getting any engine braking. The suspected part in repair matrix for “no engine braking (D position)” is 2nd Brake (B2). Not sure if my no 4th is related to this. Never thought to try 2nd or L to see if I get any braking.
My D (drive) light is out. My O/D light works when I select it. I wish it was something stupid like that.
Trunk Monkey
Moderator
No, no bigger meaning. Just that the o/d may be off and you wouldn't know it without the light to tell you.
- Thread starter
- #46
Hmmm. Are you suggesting that even if the light is off it could still be on? Because my light turns on and off selecting the O/D button.
I don't know if this will help you or not.
In 1989 I bought a Ford Probe. 3 years and about 3 months after my purchase, my Probe would suddenly shift out of overdrive on the Interstate. I and everyone I talked to thought that I was having transmission trouble. Being a broke college student and my car being 3 months out of warranty, I knew that I couldn't afford to get it fixed.
I started noticing a pattern though. I had to be at work by 6:30am, so normally would let my car warm up for 10 minutes or so before leaving. Then I drove down city streets for the first 10 minutes of my commute. On the interstate my engine temperature would fall below normal level, so the car would shift out of overdrive to "warm" the engine. The overdrive was very high geared and the engine was a 4 cylinder, so nothing like going from 2,000rpms to 4,000rpms.
I finally guessed my problem myself and it was a stuck open thermostat. 10 dollars later and the car and transmission still drives fine today.
I don't know if the 100 series has a "warm" circuit like this but, I would at least let it warm up in the driveway and then check it.
In 1989 I bought a Ford Probe. 3 years and about 3 months after my purchase, my Probe would suddenly shift out of overdrive on the Interstate. I and everyone I talked to thought that I was having transmission trouble. Being a broke college student and my car being 3 months out of warranty, I knew that I couldn't afford to get it fixed.
I started noticing a pattern though. I had to be at work by 6:30am, so normally would let my car warm up for 10 minutes or so before leaving. Then I drove down city streets for the first 10 minutes of my commute. On the interstate my engine temperature would fall below normal level, so the car would shift out of overdrive to "warm" the engine. The overdrive was very high geared and the engine was a 4 cylinder, so nothing like going from 2,000rpms to 4,000rpms.
I finally guessed my problem myself and it was a stuck open thermostat. 10 dollars later and the car and transmission still drives fine today.
I don't know if the 100 series has a "warm" circuit like this but, I would at least let it warm up in the driveway and then check it.
Trunk Monkey
Moderator
No, I'm suggesting that if the bulb were burned out and someone didn't know the button on the shifter was in the in "off" position, they might not know their o/d was off and think that higher RPMs was some other issue.
- Thread starter
- #50
My commute to work is about 10 mins on the highway. So I too let it warm up before heading out. Our 100’s won’t allow final gear until it reaches 125 temp. I changed out the engine coolant temp sensor for the heck of it. Figured I could get lucky with the cheapest part. My LC will get up to 190-195 on the highway so theoretically it should be in 4th gear.
I do not believe temperature is your problem here. From a cold start (25°F) I can back out of the driveway, take off down the county road and hit 70mph in less than 1 mile. By this time it has warmed up enough the Auto HVAC starts blowing heat and it drops into 4th gear without hesitation.
Continuing to follow the saga as I am curious to know what the problem is!
Continuing to follow the saga as I am curious to know what the problem is!
- Thread starter
- #52
The journey continues. Figured I’d keep this updated in case someone experiences the same issue. So, I finally hooked up techstream. A lot of great information this program displays.
I was trying to take pictures without running into someone else on the highway. So they’re not greatest shots. As you can see my temps are working fine.
AT temps seem to be fine as well but that shouldn’t matter it not be able to shift to O/D.
This screen shows that I’m in 4th. O/D switch (button on the shifter) is not pressed out. Not sure what 4th(M)Drive is.
Lastly, I went into active test mode to manual shift. Here’s where it gets interesting.
This test requires to drive less than 30 mph. Each shift up I physically feel the shift and see the drop in rpms except when I go into 4th. I don’t feel anything and rpms don’t drop a couple hundred like the other gears do. The rpms stay the same as they were in 3rd gear. Another interesting observation is when I start to manual downshift the rpms don’t jump up. The tach stays around 1000 rpm.
I’m starting to think this might a off-vehicle fix. Per the FSM that would be O/D Brake
I was trying to take pictures without running into someone else on the highway. So they’re not greatest shots. As you can see my temps are working fine.
AT temps seem to be fine as well but that shouldn’t matter it not be able to shift to O/D.
This screen shows that I’m in 4th. O/D switch (button on the shifter) is not pressed out. Not sure what 4th(M)Drive is.
Lastly, I went into active test mode to manual shift. Here’s where it gets interesting.
This test requires to drive less than 30 mph. Each shift up I physically feel the shift and see the drop in rpms except when I go into 4th. I don’t feel anything and rpms don’t drop a couple hundred like the other gears do. The rpms stay the same as they were in 3rd gear. Another interesting observation is when I start to manual downshift the rpms don’t jump up. The tach stays around 1000 rpm.
I’m starting to think this might a off-vehicle fix. Per the FSM that would be O/D Brake
Last edited:
When you downshift manually and the revs stay at 1000, does anything happen when you adjust the throttle at that point? Ex: in one of mine, downshifting manually did nothing until I let go of the throttle and reapplied it. Then the engine would start braking and the revs would rise.
Appx 25-2600 @70 mph. In my 99. If I am at 3100 RPM in 4th. I’m around 90 MPH
- Thread starter
- #55
Hey GA, sorry for delayed response. Just back in town today. If I’m manually downshifting in the techstream and I’m off the pedal my rpm’s are essentially at idle. When I apply gas the truck doesn’t catch on until it’s at the appropriate rpm range at that particular speed, if that makes any sense. So for instance, when I’m at 30 mph when I downshift to 2nd gear I can press the gas and the truck won’t do anything until about 1,600-1,800 rpm or so.
I talked to the ladies over at ACC and they gave me their transmission guy’s #. He recommended one more thing to try. He suggested pulling the main connector to the transmission from the ecu. It’ll most throw all sorts of codes but I should be able to try shifting through all the gears. Might get the same results from the techstream method but worth a shot.
Just something to consider, I did a mod on my 98 which allows the factory rear diff to lock in high range. Basically, I flip a switch and the transmission and ECU thinks it's in low range so I can lock the rear diff. I accidentally hit the button once while doing an interior detail and when I went for the drive afterwards, I was getting weird shifting patterns (delayed, at higher RPMs, like it does in low range) and no O/D - no O/D in low range. Not sure if your truck has any mods like that but worth a quick look. Sounds dumb but maybe your truck thinks it's in low range? Haha, wishful thinking maybe, I dunno.
Admittedly I'm not knowledgeable about transmissions, especially automatics... Can overdrive be 'manually' shifted in to?
- Thread starter
- #58
I wish it was something easy like that. A guy familiar with this vehicle knew the PO’s. They weren’t the type of people that would mod a car.
The guy mentioned that once in “D” that should be 3rd and 4th. Can’t imagine it being any different then what I was able to do with techstream. We’ll see.
- Thread starter
- #59
Who’s got 4th/OD? ==> this guy
The saga has come to a end. Took it to Landmark transmission recommended by ACC. The guys were great. Price was fair. Plus I have a unlimited mile two year warranty.
Basically what happened is the OD brake snap ring that holds the clutch in the case came out of its groove. This caused the piston that applies the clutch to move too far and cut the o-ring on the piston. The return spring cage was also damaged. Other than that I was told the rest of the unit looks good. Pretty amazing this transmission went 330k + with no issues.
Look at this. It’s beautiful
The saga has come to a end. Took it to Landmark transmission recommended by ACC. The guys were great. Price was fair. Plus I have a unlimited mile two year warranty.
Basically what happened is the OD brake snap ring that holds the clutch in the case came out of its groove. This caused the piston that applies the clutch to move too far and cut the o-ring on the piston. The return spring cage was also damaged. Other than that I was told the rest of the unit looks good. Pretty amazing this transmission went 330k + with no issues.
Look at this. It’s beautiful
Great info, glad you got it sorted out! RPM's look much better now.
