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Failed hill climb procedure


UKTJ
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I noticed a reference to a failed hillclimb test in a recent event post.  When I went on the newbie training at Slindon this was covered, but the recent reference reminded me that I wanted to check the correct procedure.

 

My recollection from the training is that the initial advice was to select reverse and then to start the vehicle without depressing the clutch and then to release the foot brake to allow for a controled decent under engine braking in reverse.  However, my TJ will only start with the clutch depressed (not sure if this is also the case for other manual Jeeps), which means that procedure can't be followed.  I believe the revised advice was to keep the foot brake on, depress clutch, start the car and then release the clutch to the biting point, then releaee the foot brake allowing for a controlled decent under engine braking.

 

Can anyone confirm if what I describe above is the correct approach in a manual that will only start with the clutch depressed?  Or have I not remembered the instruction correctly?

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There is a clutch interlock override fuse on TJs. The position varies across model years but my TJ (a 60th/2001) had it behind the glove box. Usually, you put a 20 amp fuse in the position labelled 'Clutch Interlock' or 'Auto Transmission', yes on manual transmission Jeeps. Rubicon TJs were wired without the interlock in low ratio which is what they all should have been wired like in the first place.

 

You could make a low ratio override yourself by intercepting the clutch switch signal line with a normally open relay powered by the transfer case low ratio lamp line. I have seen write-ups before but haven't saved any bookmarks for it.

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Thanks @V.  This is one of those helpful answers where my own lack of knowledge means I understand every word, individualky, but struggle with the sentences.  I think what you are saying is that it is possible to rewire the TJ so it can be started without the clutch depressed in low range.  I suspect this is beyond my competence with vehicle wiring at the moment, at least without a very clear YouTube video on subject.  Embarrassing I know, but even so, still the honest truth of it.

 

In the abscence of such rewiring, is the procedure I described as good as can be achieved in a TJ?

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I had an incident in my XJ. I can't quite remember what happened but I was stuck in a peat bog on the mountains and that stupid ,push clutch in to start stopped me getting unstuck!!! 
All I  did was get behind the clutch pedal and find the switch. I guess I pulled off the terminals and joined them together. Whatever I did, end of problem! They stayed like it and I had no probs.

I guess its the same switch in a TJ, but maybe not?

What I am sure of is that the safest procedure for a failed hill climb is the ability to stop/start in gear!

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2 hours ago, V said:

There is a clutch interlock override fuse on TJs. The position varies across model years but my TJ (a 60th/2001) had it behind the glove box. Usually, you put a 20 amp fuse in the position labelled 'Clutch Interlock' or 'Auto Transmission', yes on manual transmission Jeeps. Rubicon TJs were wired without the interlock in low ratio which is what they all should have been wired like in the first place.

 

You could make a low ratio override yourself by intercepting the clutch switch signal line with a normally open relay powered by the transfer case low ratio lamp line. I have seen write-ups before but haven't saved any bookmarks for it.

It is amazingly easy.  Just move the spare fuse in slot 19 to slot 20.  The spare fuse is provided for this very purpose and the process is included in the manual (page 68 in mine).  The fact the engineers provided for, and wrote up the process made me happy to go ahead.

 

I have linked to a super helpful YouTube video on this in the TJ technical section in case others need it

Edited by UKTJ
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Sorry, I should have clarified that the models with the fuse position for clutch interlock, disables the requirement to depress the clutch pedal to start the engine in any mode that the transfer case is in when a fuse is fitted in that position.

 

On TJ Rubicon models there is no fuse position for clutch interlock. However, you always have to depress the clutch to start the engine if the transfer case is in high ratio but the engine can be started without depressing the clutch when the transfer case is in low ratio. This special case is only for the TJ Rubicon models AFAIK.

 

I fitted the override fuse on my TJ but I still depressed the clutch when starting out of habit. On the few occasions that I had to do so off road, I instinctively left the clutch alone in low ratio starts. This goes back to when one of Jeep's instructors wouldn't let me go home at the end of a training day until I could do a failed hill climb in a manual diesel XJ three times in a row. He persevered with me into nightfall probably because I got the failed hill climb in the auto perfectly every time and most people find that harder to do without hitting the wrong selection.

 

I'm not entirely certain, but I think the earliest of the 1997 TJs didn't have the override for the interlock. Which back in the day was why some owners wired in their own override circuitry.

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44 minutes ago, V said:

Sorry, I should have clarified that the models with the fuse position for clutch interlock, disables the requirement to depress the clutch pedal to start the engine in any mode that the transfer case is in when a fuse is fitted in that position.

 

On TJ Rubicon models there is no fuse position for clutch interlock. However, you always have to depress the clutch to start the engine if the transfer case is in high ratio but the engine can be started without depressing the clutch when the transfer case is in low ratio. This special case is only for the TJ Rubicon models AFAIK.

 

I fitted the override fuse on my TJ but I still depressed the clutch when starting out of habit. On the few occasions that I had to do so off road, I instinctively left the clutch alone in low ratio starts. This goes back to when one of Jeep's instructors wouldn't let me go home at the end of a training day until I could do a failed hill climb in a manual diesel XJ three times in a row. He persevered with me into nightfall probably because I got the failed hill climb in the auto perfectly every time and most people find that harder to do without hitting the wrong selection.

 

I'm not entirely certain, but I think the earliest of the 1997 TJs didn't have the override for the interlock. Which back in the day was why some owners wired in their own override circuitry.

No apologies, I would not have looked for the video unless you had raised it!

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10 hours ago, V said:

I'm not entirely certain, but I think the earliest of the 1997 TJs didn't have the override for the interlock. Which back in the day was why some owners wired in their own override circuitry.


Early TJs had a second position on the connector block at the clutch pedal. Unplugging the connector and reconnecting it in the second position disabled the requirement to depress the clutch to start.

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That's interesting Alex. My XJ was '97!  Maybe that relates to the experience I had. 

There were a lot of similar things/ parts between Wranglers and Cherokees in those days.  My original Chrysler workshop manual contains both XJ and YJ and many procedures are the same. It highlights differences and they are few.

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The difference between ‘97s, ‘98-‘02 and after is covered in the video I linked to in the TJ Technical forum.  It really is a very helpful little video and it may well be helpful for any other Jeep with the same feature.

 

I think Jeep actually got it spot on with the feature, it is a sensible safety precaution.  Indeed, some 35 plus years ago when I learned to drive I was always taught to depress the clutch before starting a car and it is something I do automatically, so I may well find a failed hill climb procedure hard to follow (as it seems @V did in the past).  But Jeep made it possible to override the feature very simply, in a way that could be done just for times when the TJ was off road.  That was an extremely sensible approach.

 

It was 100% my error not to have read the part of the owners manual that explained the process.  And again, this forum came up trumps in setting me on the right path, even if the question I needed answered was not the one I actually asked 😳

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20 minutes ago, UKTJ said:

The difference between ‘97s, ‘98-‘02 and after is covered in the video I linked to in the TJ Technical forum.

I have watched it now and refreshed my memory and learned something new - '97 & YJ override feature.

 

3 hours ago, AlexK said:

Early TJs had a second position on the connector block at the clutch pedal.

It must have been you that told me about the 'wiring at the pedal' (your teal TJ at 'The Star'?). I have always thought it was something that had to be wired in specially, not an original equipment plug-in socket swap.

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Oh, maybe the YJ has it then  but in mine its been disconnected. I'll have to look. 

When I learnt to drive, 57yrs ago, one was taught to always check the car was in neutral!  Perhaps that was the dark ages!

I agree it becomes automatic!

Edited by digger
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51 minutes ago, UKTJ said:

The difference between ‘97s, ‘98-‘02 and after is covered in the video I linked to in the TJ Technical forum.

 

Apologies, us freeloaders can't access the Technical forum so I was relying purely on my ever-fading memory.

 

3 hours ago, digger said:

That's interesting Alex. My XJ was '97!  Maybe that relates to the experience I had. 

There were a lot of similar things/ parts between Wranglers and Cherokees in those days.  My original Chrysler workshop manual contains both XJ and YJ and many procedures are the same. It highlights differences and they are few.

 

Must confess I've never looked to see if the same feature exists on XJs, but as you say, Chrysler were masters of parts sharing and the electrical architecture of facelift XJs was almost identical. I'd almost put money on it being there.

 

That sharing went as far as '97 TJs needing the XJ's remote central locking key fob to disable the factory immobiliser, leading to the somewhat comical situation of having to press a button marked UNLOCK despite still having to put a key in the door and turning it. Thankfully replaced with SKIS in '98.

 

20 minutes ago, V said:

It must have been you that told me about the 'wiring at the pedal' (your teal TJ at 'The Star'?). I have always thought it was something that had to be wired in specially, not an original equipment plug-in socket swap.

 

It was detailed in the manual, I believe. I think I made the switch on my green Sahara - my first TJ and one of the first in the country - fairly early in its life and it stayed that way forever. Although, like many, I had already long developed the habit of depressing the clutch when starting. That Jade TJ (my second, I think) was a right pain.

 

In case anyone isn't aware, the clutch interlock arose because of a large number of lawsuits brought by US owners who'd propelled themselves through their garage wall and into their house, as a result of starting their car while in gear.

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3 minutes ago, AlexK said:

Apologies, us freeloaders can't access the Technical forum so I was relying purely on my ever-fading memory.

Apologies, I knew Silver members could not post there, I did not remember that they could not view the content.  Link posted here for anyone needing it…

https://m.youtube.com/watch?v=u00V3gmQ_uM

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Referring to the title of this post, the situation described at the beginning is specifically about stalling a manual transmission Jeep on a hill climb. You can fail a hill climb without stalling the engine.

 

The technique is when you recognise that you no longer have forward motion up the hill, that you brake and change into reverse gear simultaneously. This is so braking on the wheels only needs to hold the Jeep momentarily before the clutch is re-engaged. As soon as the Jeep is in reverse gear, you can feather the brake to start reversing back down the hill. It's a technique that needs to be practised as you have less than 2 seconds to perform it when need be.

 

Depending on how slippery the surface is, feathering the brake can turn into releasing the brake completely and accelerating in reverse to avoid the tyres losing grip and steering. If you lose steering by locking up the front wheels, you can get into a rollover situation quickly. "As slow as possible and as fast as necessary" still applies.

 

On a failed hill climb I will spend more time looking at where my front tyres are pointing as I would the path I am reversing into. This is not something that is often taught. When you have narrowly missed a rollover on a failed hill climb, you naturally develop a bias towards doing so. It is very important to keep the tyres pointing in the direction of travel and not to steer off course accidentally. On the steepest gradients, I wont even look behind me, I will just stick my head out the window and watch my front tyres until it is safe enough to look back. Don't follow me closely up a gradient until you've seen me clear it!

 

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Very helpful @V, the training at Slindon only covered a stalled vehicle IIRC.  But I also had the benefit of @digger's guidance on an unstalled fail when he took me around Aldermaston (I still feel guilty that his kindness resulted in damage to his YJ that meant he could not drive it for yhe rest of the day), but a reminder is very welcome for a relative novice like myself.

 

To avoid confusion for other beginners like myself, the clutch interlock is only an issue when a TJ has stalled.

Edited by UKTJ
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You should not feel guilty T. What happened was entirely my fault!        (What a shame the idiots who drove into the garage wall in the other post couldn't see that it was theirs too!)

I always try to analyse any issues after the event. In that case my conclusions were:- 

1. Due to enthusiasm plus the fact that I had done that obstacle in the past I didn't bother looking first!  Bad decision, I think it was muddier and deeper!

2. I nearly did it on first attempt but slid back into the bomb hole. On next attempts I could barely climb the slope forwards, whereas backwards ( less steep) was ok. I believe this was because I had broken the front driveshaft first time but I had failed to realise what had happened.  Doh!

3.Still unaware of the damage,  I reversed out and tried to bridge the ruts. However immediately the front slipped in sideways followed by the rear, resulting in the tip over.  The task should have been simple but with no front drive there was no traction.  Another mistake!  Hopefully I learnt something. Certainly this game seems to me to be something where one never stops learning!

Have fun, see you next time!

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The clutch interlock is an issue on any manual transmission 4x4. The TJ has an override mechanism but I don't know if other manual transmission Jeeps also have the capability. It hasn't been something I have looked for in the past. I guess checking the wiring diagrams for each model will reveal the facts.

 

Automatics have a Neutral Safety Switch (NSS) that prevents starting in selections other than 'N' or 'P' but these can often be bypassed by shorting pins in the socket for the NSS plug harness although not recommended. It is possible to stall an automatic on a hill climb but it is a lot less likely. Going back to my off-road training decades ago, the ZJ auto that I learned in was I believe able to start in 'R' after the wheels started rotating. My instructor took me specifically to an obstacle that could stall an automatic because I didn't believe it was possible. I don't remember stalling an automatic off-road since learning how to restart a stalled automatic on a hill climb. I learned how to do engine restarts on failed hill climbs on both a post '97 2.5TD manual XJ and a late model 4.0L auto ZJ. Both were vehicles in Jeep's own training fleet and may have been modified to do this. I really don't know for certain, there was a lot to take in that day. However, my experience does suggest that the pedal switch alternative socket/plugs may be present on a manual XJ as I spent hours learning how to do it in one. I also did three consecutive restarts in the auto ZJ rolling backwards in reverse, so this is either a little known feature of the ZJ transmission or an NSS mod. In more than 20 years driving automatic Jeeps off road, it's not something I have considered important enough for me to check on my own Jeeps.

 

From memory, the technique to deliberately stall an auto on a hill climb is as follows. Don't try it on a steep gradient, you don't need much of a slope. Also don't try it unless you have a clear run off backwards and plenty of distance to think in.

  1. Drive up the gradient in a forward gear in low ratio with a reasonable amount of commitment (but not too fast).
  2. When you are ready to stall, take your foot off the accelerator pedal quickly. Momentum of the Jeep will carry it forward a bit and then it will start to roll backwards under gravity while still in a forward gear. The remainder has to be done as fast as humanly possible.
  3. The mismatch between what direction the transmission gears are in and the new direction of wheel rotation cause the engine to stall. Hold the steering wheel tight with your right hand only and brake hard now to stop the wheels rotating. This is double plus not good on a steep slope if you start to slide.
  4. With the wheels stopped rotating, with your left hand either shift into 'N' very quickly, then grab the steering wheel with the left hand. Restart the engine with key turn using the right hand, then grab the steering wheel with the right hand. Using your left hand, shift into 'R', feather the brakes and reverse down the hill. Alternatively, instead of shifting in to 'N', shift in to 'R' then taking your foot off the brake and try to start the engine with the wheels rotating backwards and torque converter turning. If the NSS is active you can only do the first method, if NSS is overridden by wheel rotation you will be able to start in 'R'.

If you are going to practise this, make sure others around you know what you are doing in advance so they can give you space. It is much better to do this specifically in a designated training area.

 

I just visualized my technique, I realise now that I don't look out the front or rear windscreen when doing the restart. As soon as the engine stalls I focus my vision only on the transmission selection legend, not the handle, only the shifter shaft at the gate position I need to shift to. I can turn the ignition key without looking. There's no need to look out front as you have either stopped now or are rolling or sliding backwards. There is also no point in looking out the back either. Anything that is too close will become your brakes, don't waste any time thinking or looking elsewhere. Hit that 'N' selection in one movement and the moment it arrives in 'N' you have synchronously started the turn of the key, focusing now on 'R' so as soon as you can hear the engine running or have revs on the accelerator pedal you are shifting into 'R' in one movement without hitting 'P' and releasing the brakes as soon as it is in 'R'. Now you can look at your front tyres and where you are going.

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Stew the Jeep

Foot on brake depress clutch start engine release clutch and back down using engine and foot breaking 

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I agree with both V and Stu.

I thought it worth saying a bit more about''feathering the brakes'' for those who don't know whether on a slope or the flat.

The thing is you can use the brakes any time but you cause a serious slide issue if you lock the wheels up. That is what you must avoid and that is why you must not disconnect drive (such as using clutch)  If your wheels lock up you  become a toboggan, very dangerous!  So gently'feathering'/ touching/pressing  the pedal will help slow you but you must be careful. Alternatively you can just tap the pedal, gently, on and off which will also have the same result. If your bottom gear is still too fast when descending forward this works well to slow you. Which method you use is your choice but you need to practise.  I prefer the latter as its automatic for me  having used it in off road racing.

In the days before ABS more knowledgeable drivers learnt a technique called ''Cadence Braking''  which was taught in  the Police roadcraft etc. It still applies today for cars without ABS.  It involves stamping hard ,on and off the pedal , while trying to maintain stability for an emergency stop on slippery surfaces. It works well but needs to be practised thoroughly. 

Another rapid or emergency stop technique on any surface is to stand on the brakes without depressing the clutch pedal until the very last minute(only to avoid stall and or lockup). If you try this on a large flat greasy place you will be surprised by how much it can shorten your stopping distance and improve stability,  if you try it ,at the same time, in comparison to the standard driving test method ie clutch and brake pedals to the floor!

If you are interested in these things please do not try, without practising some where safe first, preferably with help. As V suggests ask instructors who are with you.

Hope this helps some one.

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