M1009 - Speedo Cable

[cmroles]

I replaced the speedo cable a while back due to wild fluctuations of the speedometer needle. What is strange is that the speedo works beautifully now when its warm outside, but still goes crazy when its cold. When its cold, it will settle down and work normally after driving for around 20 miles. First it stops fluctuating, but it will read 15-20 mph too fast, then as it fully warms up it will begin to read correctly. Once fully warm, it indicates about 1-2 mph faster than my actual speed (based on gps).

I'm thinking the problem may be in that little speedo gear adapter box at the T-Case. Has anybody else seen something like this before?

 

[bigjmcconnell]

I don't know if this helps or not but I had a similar thing going on with my Jeep (Not a MV...)

Mine turned out to be a problem within the actual speedo itself. Although I have a NP208 that came out of one of my M1008s that has the plastic speedo gears all stripped inside. I never drove it though so I can't say if the symptoms were the same as yours.

It might be worth pulling the tailhousing on the t-case to check it out.

 

[rod]

I replaced the speedo cable a while back....

I need to do the same. Do you have the Parts number of the one you bought (assumming you bought it) ? The auto parts stores list a couple in different lengths and I want to make sure I get the right one. I think the correct one is 100" long but not sure.

 

[Barrman]

I agree with the speedo is the problem. Mine did as yours seems to do, I cleaned and oiled the moving parts on the back of the speedo and all was well until last Friday. First time it has been above 90° inside the truck in a few months. Now it bounces around at all speeds. I pulled the cable insert out, cleaned and oiled it. Now it just bounces around below 40 mph, but seems to be indicating where it should which is 5 mph slow with the bigger tires.

I will pull my speedo out again to clean and lube to see if that fixes it. Again.

 

[cmroles]

I need to do the same. Do you have the Parts number of the one you bought (assumming you bought it) ? The auto parts stores list a couple in different lengths and I want to make sure I get the right one. I think the correct one is 100" long but not sure.

Part number is 615-1615 from NAPA. The first one I bought was from O'Reilly and turned out to be about a foot shorter than the original. Went to NAPA and just got one for a civvy Blazer and it worked perfectly. I thought it was fine until it got chilly the other morning and went bonkers...

 

[K9Vic]

Mine broke (Snapped)on my last weekend while I was far far away from home after any parts store were open, but I had a GPS so I was able to know how fast I was going. I had replaced it back in fall 2010 and I think I got the wrong one at 120" as it probably was too long and bent the wrong way some place. I got the 100" on today and it fit much better and looks much better. Hopefully it will last me a long time now, but maybe I should grease it every few months, especially after major off-road runs.