Controlling speed when going downhill...

[jetmaker]

I have a 2000 XLT with an automatic transmission (5-speed --> 3 + 2OD). When going downhill, even on relatively modest grades, I have to ride the brakes to prevent from developing excessive speed. I've tried downshifting, and that does not seem to alivieate the problem. The only remedy I have found is to move the transfer case to 4x4 LO. This of course is not very practical in the city, and even in some remote trails.

Can someone explain if this behaviour is normal. If it is not, what might be the cause and what should I have the shop look at first.

Thanks for the help.

Regards,

jetmaker

 

[IAmTodd]

Thats normal. Try hitting the OD off button when going down hill, it will give back you're engine braking, but it will make the engine rev more because you you'll be in 3rd gear.

 

[X~FACTOR]

What do you consider excessive speed?

 

[Alec]

Your auto tranny actually doesn't have 2 ODs, FYI. 4th gear is 1:1 and 5th is OD. I know your gear selector says 1,2,D (OD), but it's really 1,2,4 (5).

Just trying to help.

Anyway, it's a heavy truck without hill decent control. I would not make a habit of shifting into 4lo, and you have to be careful when shifting out of D into 2, but that should help as long as the RPMs in 2 won't be too high.

 

[jetmaker]

Thanks for the replys.

I'll try these things again, just to make sure. However, the problem is that there appears to be no engine braking. The engine rpm remains low, around 1000 rpm during downhill decents, even when shifting into lower gears.

By excessive speed I mean that the vehicle keeps accelerating due to gravity. If I took my foot off the brake, the truck would just keep going faster.

I am a manual transmission kind of guy. I am use to downshifting and feeling the noticable decelleration that follows due to the engine braking. I hardly notice this behaviour on my automatic. With a manual, I would downshift to 2nd or 3rd gear, and let the truck drive itself down. With the automatic, it just feels like a runaway.

Later,
jetmaker

 

[Alec]

Has it always felt like this, or is this something recent?

The tranny should not be effectively going into neutral. Even if the torque converter is slipping, the tranny should provide engine braking unless the load is too much for it and the computer "gives up".

 

[Jefe]

If you do not have engine braking in 1st or 2nd it is a known problem with our 5 speed autos. check this thread for how to fix it:
Dead Link Removed

 

[jetmaker]

Alec,

Has always seemed to be this way.

jetmaker

 

[IAmTodd]

Have you tried it w/o the overdrive? This is what mine does when OD is on, when its not on it acts like a free wheels, no like its in neutral, just like it has less resistance holding it back.

 

[jetmaker]

The truck is going into the dealership to be looked at tomorrow. I'll post the results after they have had their go at it.

However, the concern I have is that the dealership really does not know how this is suppose to work, so I am wondering if others can give me their experiences. This is how I am testing mine.

Accelerate to 20 mph in D, then downshift straight to 1st gear. Does the engine provide braking, or does the vehicle just coast?

In my case, when the tranny is cold, the engine brakes... but when it is warm, it just coasts and the engine rpm drops to idle.

I'd appreciate any other peoples experiences using this method.

Thanks,

jetmaker

 

[Jefe]

Originally posted by jetmaker
The truck is going into the dealership to be looked at tomorrow. I'll post the results after they have had their go at it.

However, the concern I have is that the dealership really does not know how this is suppose to work, so I am wondering if others can give me their experiences. This is how I am testing mine.

Accelerate to 20 mph in D, then downshift straight to 1st gear. Does the engine provide braking, or does the vehicle just coast?

In my case, when the tranny is cold, the engine brakes... but when it is warm, it just coasts and the engine rpm drops to idle.

I'd appreciate any other peoples experiences using this method.

Thanks,

jetmaker

i don't think 1st is going to kick in at 20 mph. Try putting it in 1st, speeding up to 3500 rpm, and then letting go of the gas. it should stay in 1st and slow you down. However if you have the problem I posted a link to, it will instead pop into neutral and coast. Before I fixed mine, however it would provide engine braking in 2nd.

 

[jetmaker]

Jefe....

Actually, when the tranny is cold.. it does shift into 1st. But it does not after the tranny is warm.

I followed your link, and spoke to a few dealerships about the Service Report. They say it is not applicable to my year... nor is it the issue. However, I'll find out when the dealer gets a look at it.

I'm trying to get a grip on what other people find. Try downshifting at 20mph and let me know the result. By the way... tried it in first.. vehicle accelerates fine.. then drops to idle when I take my foot off the gas.

Looking forward to hearing some responses.

jetmaker

 

[Jefe]

Originally posted by jetmaker
Jefe....

I followed your link, and spoke to a few dealerships about the Service Report. They say it is not applicable to my year... nor is it the issue. However, I'll find out when the dealer gets a look at it.

They are right about the Service Report not covering the '00 trucks, even though the problem still exsists. Which is why i fixed mine myself.

I will see about shifting into 1st at 20 mph. Do you get engine braking in 2nd?

 

[RangerX]

Originally posted by jetmaker
I am a manual transmission kind of guy. I am use to downshifting and feeling the noticable decelleration that follows due to the engine braking. I hardly notice this behaviour on my automatic. With a manual, I would downshift to 2nd or 3rd gear, and let the truck drive itself down. With the automatic, it just feels like a runaway.

I think your answer is right there. You're a manual tranny guy. So am I, for 25 years straight. And I've learned that there is no comparison between stick engine braking, and auto engine braking. One exists, the other doesn't, relatively speaking.

 

[jetmaker]

Jefe,

Yes, I do get engine braking in 2nd. This is what makes me think that you are correct about the service report. But we'll see what the dealer does about it.


RangerX,

I realize that manuals and autos do not have the same engine braking capability, but hell... to have none... shessh.... Maybe I can get Ford to pay for the brake job when they find the problem with mine. Nice thought eh???

I should be reporting back shortly on the diagnosis.

Later,
jetmaker

 

[RangerX]

Another thought I had. What is your axle gear ratio? If it's 3.07 or 3.27, it would have a greater effect on downhill speed vs. 3.73 or 4.10.

 

[jetmaker]

RangerX

4.10

 

[jetmaker]

Ok.. the verdict is in...

Cause: Valve Body Gasket
Correction: TSB 03-22-10 (supersedes TSBs 03-11-9, 02-13-8, & 02-08-2)
Cost: 2.9 hrs of labour ($220.26), parts ($57.69), misc ($19.68) & must'nt forget taxes ($24.70). = $322.33.

TSB 03-22-10 is for vehicles built prior to 12/01/2001 that exhibit the following conditions:

- No 2nd gear
- No 3rd gear
- No engine braking in Manual 1st.

It applies to"
-Explorers, Rangers, Aerostars, Sport Tracs and Mountaineers. Typical years are 1995-2002.

It is relevant to the following transmission:
- 4R44E, 4R55E, 5R44E, & 5R55E

If anyone is interested in the TSB, let me know and I'll see if I can scan it in and then post it.

Thanks for all the help everyone.

jetmaker