1995 Safari Sahara Allison 6sp tranny will not go into gear

[chollenback]

I have a 1995 Safari Sahara. We drove it all around this summer and even went to Canada with no issues. I parked it about 2 months ago and was scheduled to get it inspected today and it would not go into gear. It has a 6 speed allison transmission. At first I was able to get it to go into reverse and then back to neutral but not into drive. Now when I push on D, R, or N none of the buttons will put it into gear. I stopped and started it again (after leaving it off for a few minutes) to see if I could reset it and no luck. Any idea what is causing this. It worked great the entire year with no issues. Thanks

[wolfe10]

If engine idle speed is too high, the Allison will NOT go into gear. Check that first.

Have you checked for diagnostic codes (from driver's seat using shift pad?  If you need the "how to", let us know.  It takes less than 2 minutes.

One of the most common issues is that the connections at back of shift pad and/or Allison ECU are a little loose and not communicating well. If that is the case, DeOxit is an excellent product to use on the connections.

[chollenback]

I also wonder if it is due to being cold. I did some research and they said cold can be an issue. it has been around mid 50's to low 30's here. I let it idle for 15 minutes and I got reverse and neutral to work but not drive. Some say the pad gets tough due to cold and does not get flexible enough to push down.

There are no engine lights on dash. Would it still throw code? Can you give me the "how to"?

Thanks Wolfe

 

[wolfe10]

To check for transmission codes (unrelated to engine light/engine codes on your year model):

 

Ignition on, engine OFF

Push the up and down arrows on the Allison shift pad at the same time.

That should bring up d-1 (for diagnostic code 1).  It will then give you a two digit code which you can look up in your Allison owners manual or on Allison's website.  If there is a code, after copying it down, push the mode button to bring up d-2.  Continue until you get a d- "some number" and - - which means there are no other codes.

On later models, the first push of the up and down arrows brings up O-L for oil level.  In this case, just push the up and down arrows again to bring up the diagnostic codes.

Let us know what you find.

 

[manholt]

Found by accident, that if your on cruise control for fast idle, it will not go into gear!

[wolfe10]

Yup, idle speed too high (for whatever reason) and all the Allison shift pad will do is BLINK.

It is smart enough to protect itself.

[rayin]

Temperature is not the cause, I've started our MH in below zero temperatures (using engine heater of course) without experiencing  any issue with the Allison going into gear. Could it be low on transmission oil? Of course it's not possible to tell when the transmission is cold unless your dipstick is marked for cold measurement.

[Lenp]

Not sure if it will help on the allison but with some engine issues disconnecting the chassis batteries for a few minutes may reset things.

Lenp

[richard5933]

Have you checked ground connections? Things worked when you parked and after two months of parking in the summer they don't. More than enough time in the hot/humid summer for some corrosion to interfere with a ground connection. No ground connection - no controls. A 1995 rig is old enough to have problems with ground connections being corroded and/or loose. Lots of posts for similar issues on the bus conversion sites for guys running the Allison auto transmissions. I second the vote for DeOxit to help clean up problem or questionable contacts.

Seems that it's common for everyone looking for a bad connection to go around jiggling and pushing on every harness connector they can find, when all along the problem is the single wire that connects the system to the chassis for ground. Couldn't hurt to check the large grounding straps at the same time, which may look good on the outside but be rotted on the inside. Not sure where your grounding straps are, but usually between engine/chassis, trans/chassis, etc.

[kaypsmith]

17 hours ago, wolfe10 said:

DeOxit is an excellent product to use on the connections.

As Brett said. And can be used on any electrical and or ground connection.

[dickandlois]

Just .

Remember! Deox-it is flammable and can react with plastics. Turn off or remover all power and all ignition sources before using it on power switches, Transfer Switches and control board connections.

 Always spray some on a cloth or paper towel and wipe a spot-on plastic equipment to test for surface damage before using.

[richard5933]

Here's a link to manufacturer's page about the varieties of DeOxit. There is a link for a PDF file which compares them and tells which are generally safe for plastics. That said, doing a test is always a good idea.

http://store.caig.com/s.nl/sc.2/category.188/.f

 

 

[chollenback]

i checked code using Wolfe's instructions. The display shows OL and then 70 then OL. 

I think OL is oil level and 70 appears to be sump pump temperature. I further looked and it could be air in line etc., I did not have any fluids changed for Tranny so maybe temperature? How would I warm up tranny. I let it idle for 15-20 minutes and it still did not work. 

Thoughts

 

[richard5933]

Have you pulled the dipstick to check the level in the tranny?

If the tranny temp is 70 degrees, then I can't see how that would be problematic at all.

Perhaps the 70 is referring to the oil level? As in, 70% full. If so, then maybe it's low on tranny fluid.

[chollenback]

Just checked it and it is full. It was cold and level is at dipstick mark

[chollenback]

Not sure if Tranny temp ever got to 70 degrees yesterday. I wonder if I use heat gun on it to warm up fluid if that will help. It has been cold nights. Fluid appeared to be clean and runny ( not thick like cold oil). 

[chollenback]

I found this link. OL 70 is low sump oil temperature. http://westernstatestransmissions.com/html/trouble1.html 

i will get heat gun out and see. I will let you know

[wolfe10]

STOP.  Unless you have driven 25+ highway miles, low oil temperature is correct/normal. No need for an IR gun or other fire drill.

Did you push the up and down arrows a SECOND time.  That would bring that generation of Allison equipments (you are at the very first of "check oil level from the shift pad") diagnostic codes.

 

From my post above: ... the first push of the up and down arrows brings up O-L for oil level.  In this case, just push the up and down arrows again to bring up the diagnostic codes.

[chollenback]

I did not drive it. Would not go into drive. I hit arrows once and arrow down. First touch was the OL and second touch was 70. I did it again and got  - - symbols. Did I miss something? Do I have to clear codes? I

[chollenback]

I will try again tomorrow just to confirm that I did it right 

[wolfe10]

If the first push of the up and down arrows brought up OL, all you do is push them again and it WILL bring up d-1 and any diagnostic codes.

 

Again, a little surprised that a 1995 has the "check oil level from the shift pad" feature, but that is a good thing.

[manholt]

As Brett said, in the start of this tread, look at connections to the shift pad.  Also ground.  50 day & 30 night is not your problem!

[chollenback]

Code is d1 23 12. I will look up code and see if there is something I can do or if it as easy fix. 

[wolfe10]

Fault code 23-12 is the transmission shift selector not communicating properly with the ECU.

Start by checking connections to the back of it (the selector pad) and to the ECU.

If that doesn't do it, just google Allison code 23 12. Lots of troubleshooting advice.  Really depends on your electrical diagnostic abilities.

Worse case is there is a tech in the Fort Worth TX area who specializes in diagnosing and fixing Allison shift pads and ECU's:

Allison ECU and shift pad repair. 866 439 9779 John Kopalek.

[chollenback]

Thanks a ton Wolfe. As long as it is not a major issue I fell better