No overdrive problem

[Lt.Dan]

My truck will not go into overdrive at all. I have no idea what could be causing this and want to get it figured out. Also i can feel my torque converter lock up but it slips in and out. the overdrive solenoid has been replaced os idk what else could cause this

[swirvin21]

Does the dash show O/D Off? The solenoid sensor has a temp gauge built in and automatically disables O/D whenever it senses an overheating issue. Sometimes the sensor goes bad and can do that.

[Lt.Dan]

It doesn't show the od is off. But my od never works. It has a new od solenoid in it. Does that come with a new od solenoid?

[ramthis9501]

I accidentally pulled the transmission relay out of mine a long time ago without realizing it. It threw it into limp mode, which is 3rd gear for mine. So it wouldn't shift at all until I put the relay back in. Is yours going through the gears like normal?

[Lt.Dan]

Yeah it goes through em fine. But it's just like having a 4 speed no overdrive transmission.

[Okiespaniels]

I pulled this from my factory svc manual....


1. O/D Switch In OFF Position. 1. Turn control switch to ON position.

2. Overdrive Circuit Fuse Blown. 2. Replace fuse. Determine why fuse failed
and repair as necessary (i.e., shorts or
grounds in circuit).

3. O/D Switch Wire Shorted/Open
Cut.
3. Check wires/connections with 12V test
lamp and voltmeter. Repair damaged or
loose wire/connection as necessary.


4. Distance or Coolant Sensor
Malfunction.
4. Check with DRBT scan tool and repair or
replace as necessary.

5. TPS Malfunction. 5. Check with DRBT scan tool and replace
if necessary.

6. Neutral Sense to PCM Wire
Shorted/Cut.
6. Test switch/sensor as described in
service section and replace if necessary.
Engine no start.

7. PCM Malfunction. 7. Check with DRBT scan tool and replace
if necessary.


8. Overdrive Solenoid Shorted/Open. 8. Replace solenoid if shorted or open and
repair loose or damaged wires (DRBT scan
tool).

9. Solenoid Feed Orifice in Valve
Body Blocked.
9. Remove, disassemble, and clean valve
body thoroughly. Check feed orifice.


10. Overdrive Clutch Failed. 10. Disassemble overdrive and repair as
needed.


11. Hydraulic Pressure Low. 11. Pressure test transmission to determine
cause.


12. Valve Body Valve Stuck. 12. Repair stuck 3-4 shift valve, 3-4 timing
valve.

13. O/D Piston Incorrect Spacer. 13. Remove unit, check end play and install
correct spacer.

14. Overdrive Piston Seal Failure. 14. Replace both seals.

15. O/D Check Valve/Orifice Failed. 15. Check for free movement and secure
assembly (in piston retainer). Check ball
bleed orifice.

The symptoms you describe suggest tranny failure...same things happened in mine as it died. OD went then TC clutches failed...but maybe its a minor issue. How many miles are on the tranny? Is the fluid starting to smell?

I have other diagnostic charts availible too.

[BMRbrnSNRbrd]

Wow Al. Nice info.

[Lt.Dan]

Wow. That is a mouth full. But the fluid doesn't smell. And I'm not sure how many miles are on it. It's a built transmission and was done before I got the truck.

[Lt.Dan]

And also the truck hasn't had over drive since I've owned it. I've never noticed. (weird I know) but just kinda assumed it came with the territory on a big lifted truck since most of mine have always kinda ran high rpms due to the bigger tires.

[trouble]

Do you have any way to check codes?

[BMRbrnSNRbrd]

Could the problem be that the transmission was built to not go into overdrive? Maybe the assumption was that overdrive clutches would be too weak for turning such large tires with so much torque?

[ramthis9501]

So wouldn't that mean he only has a 3 speed transmission? Lol

Overdrive is 4th gear in these transmissions right?

[Okiespaniels]

Yes it should be 1st, 2nd , third, lockup, and Od. What he describes would be like a late 70' s-80's vintage 518 with 3 speeds and lockup. What year is the truck? 2001?

Od should still occur...however there are electrical mods to disable the selenoid from actuating OD. You can add a relay and change the wiring so when the engine is started OD is off. Then you use the OD switch to turn OD ON.

I think grounding the OD selenoid would work but I would think that would throw a code.

Dan, do you run 3:55 or 4:10 gears? Maybe thats why the builder disabled OD, but I would think the tranny would run hotter. When OD engages the tranny is in a mechanical lockup and the TC and planetary are in a free spin mode. At least thats how I'm reading it. The fluid is not under load so it cools down. Using TC lockup only would be a load even on the thickest TC clutch facing.


Dave, cut and paste is an amazing thing. :)

[Lt.Dan]

That's what I'm thinking is that there actually is no overdrive in the transmission. I mean it goes into 4th gear. Cuz it'd be awkward to run 110 mph in 3rd gear. But yes trouble I have checked codes and there is nothing that has came up about overdrive or the tranny in general. I'm at a complete loss.

[Lt.Dan]

I'm not entirely sure what gears are in it actually, Al.

[trouble]

4th gear is overdrive.

[Lt.Dan]

Now I feel like a complete f***ing retard...

[ramthis9501]

Haha don't it happens to the best of us. Next time you drive it going down the road, push the button on your shift lever, that turns O/D on and off. If it jumps up the rpm's, that means its working and kicking it up into 3rd gear. Push it again and it'll shift back into 4th (O/D). That'll verify that its still working. There's also a little orange light that comes up on the dash that says "O/D off" when you push that button.

[Lt.Dan]

I knew that lol but I have noticed a difference now. Idk I'm a jackass.

[ramthis9501]

Well at least we know your transmission is ok now! Lol

[Lt.Dan]

Yeah. Just made an ass of myself about it. Hahaha. Embarrassing.

[Okiespaniels]

You'll get over it...I'm still not sure what you figured out.
But I'm glad you did. Education cures ignorance.

[Okiespaniels]

Haha don't it happens to the best of us. Next time you drive it going down the road, push the button on your shift lever, that turns O/D on and off. If it jumps up the rpm's, that means its working and kicking it up into 3rd gear. Push it again and it'll shift back into 4th (O/D). That'll verify that its still working. There's also a little orange light that comes up on the dash that says "O/D off" when you push that button.

Actually this is partially true. You're od doesn't engage but your tc lockup does.

I think this is where the confusion comes. Our trannies are actually 3 speeds with a lockup converter and overdrive.

I am told you can disengage the tc but you have to dig into the pcm wiring harness.

[ramthis9501]

Transmissions are confusing... Haha

[Okiespaniels]

I used to think that...until I started studying the manuals...I understand a whole lot more now than i did. Maybe only enough to be dangerous, but it least it's not some kind of "black art" any more.

Are you still haing an issue with the od or tc slippping? That could become a real issue!

[ramthis9501]

Luckily mines still doing good!

[Okiespaniels]

I know this is off topic, but I wonder if theres a way I could download this manual I have on to the forum so you guys could have a copy.

[ramthis9501]

That would be helpful! I'll send you a PM real quick

[trouble]

Actually this is partially true. You're od doesn't engage but your tc lockup does.

I think this is where the confusion comes. Our trannies are actually 3 speeds with a lockup converter and overdrive.

I am told you can disengage the tc but you have to dig into the pcm wiring harness.

With o/d on the trans shifts 1,2,3,4,+t/c.
With o/d off the trans shifts 1,2,3,+t/c.

[DoubleTakeDodge]

When i turn my overdrive off it spikes the RPMs through all gears and keeps the truck at a higher range to make it easier for towing/accelerating with a trailer without putting too much strain on the truck. Jerrod's problem is that it doesn't do that. With the overdrive on or off it runs the same. However, that may just be how diesels are set up because the make stupid amounts of torque compared to a gas motor.

[Lt.Dan]

Yeah. I'm only noticing an rpm jump (although really slight at around 65 mph.

[DoubleTakeDodge]

What about on your fords? were they different? or do you remember?

[Lt.Dan]

Come to think of it they were pretty much the same

[Okiespaniels]

With o/d on the trans shifts 1,2,3,4,+t/c.
With o/d off the trans shifts 1,2,3,+t/c.



I thought sean told me different. How much should the tc lock up drop the rpms>? I klnow theres a dynaflow takes place and I always thought it was the tc.
Either seans confused or he's confused me. Pat is correct tc lockup should be last.
Is your TC locking up? You should see a several hundred rpm drop even on a diesel. I go from 1800 rpm at 42 mph to like 1200 rpm when the tc locks.

[trouble]

I thing the gear change is about 750 and the t/c like 250. When i'm on the highway ( 60 -70 -80 whatever ) the shift from 3rd to 4th +t/c will generally drop 1000 rpm. My 97 will lock up the t/c when it shifts to 4th.

[trouble]

Lt.Dan, i will be in Tulsa sunday if you want i could bring the the box with me so we could hook it up and see what it's doing.