If you’ve been in the loop, you know that I’ve been ‘just about’ to get a new car for about 2 years now. I get into some test drives, kind of narrow it down, then decide I’m just as happy with the old car and don’t want to have car payments again. Yep, the 15 year old Nissan is still running strong and this year I should top the 200k mile mark. But to help myself along the process, I’ve been fixing all the little niggling problems that I would need to in order to sell my old car. One of which has been a problem I’ve had for the last two years – and this one turned out to be really cool.
The problem was that on very cold mornings (i.e. only in winter), when you turned it on, the speedometer would jump to 30-40mph – while you were still in park. If you put it in gear, it had no power and wouldn’t shift into overdrive. On REALLY cold days it would be stuck at 0mph and wouldn’t even shift out of first. You had to wait about 5 minutes for it to warm up and then it would be perfectly normal. At first I thought it was a transmission problem – so I didn’t do much with it as a rebuilt tranny would be about 1/2 the value of the car. But with a possible sale pending, I knew I needed to at least know what the problem was for full disclosure to the person buying it.
I took it to a great transmission guy I know – and he said there was nothing wrong with the transmission at all. No codes, everything is fine. Instead, he said, what was happening is when the speedometer was reading 30, the car thought it was going 30, and shifted to 3rd gear (hence no power). When it was stuck at 0, it wouldn’t shift because the car thought it was going – well – zero mph and should stay in first. He sent me to an electrical guy that reproduced the problem and found that all the speed sensors and engine sensors were working fine. It wasn’t in the sensors or wiring – it was in the actual speed cluster itself (pictures are from when I tore the heater core out – how’s that for lucky!). Huh? The actual instrument cluster was causing bad shifts? I had a hard time swallowing that at first, but he seemed sure. Problem was that a new speedometer cluster was $950 – that’s more than what it would have cost to get a rebuilt transmission put in my car. Sigh. He didn’t have a line on any used or refurbished ones because I have a really unique speedometer cluster – one that has a heads up display. Yep, my 15 year old car has a fighter-pilot era polarized glass/heads up display. I wasn’t ready to dump that kind of money – so I told him to hold on while I made a few phone calls.
I called my favorite junk yard – and they happened to have a 93 nissan altima in the lot. I had them pull the cluster and they charged me a much more reasonable $50. I took it to the mechanic guy who put it in, but it then wouldn’t read any speed, nor shift out of first. Huh. It was from an automatic car – but the junk car didn’t have a HUD. Could it make that much of a difference? The backs were almost identical – minus the HUD sending unit. I also picked up an interior light dimmer switch for $5 from the same junk car because mine seem to have a short in it and would blink the interior lights when it went wacky.
Off to the Nissan forums, posted the question/pics, and got an answer back – better than an answer actually. Answer is that in Altimas, the non-HUD clusters don’t work in HUD cars and vice-versa because the speed sending units are analog vs digital (respectively). But this guy actually has a HUD cluster he’ll sell me for $60. I buy it and go to a speedometer shop (because I was very unsatisfied with the previous shop as they left my dimmer unplugged so I had no interior/console lights when driving at night and they were very slow/a day late on the work they did) where he rolled the odometer to match the old mileage and plugged it in (I also leaned over and put the new dimmer switch in at this point and verified the old one had a short). Voila. It shifted (and the lights dimmed!), but would it solve the problem? I would need to wait for a cold morning. Note on this kind of work: I would have done it myself (20 minutes worth of work), but you need a shop that will officially vouch for the mileage or you get nailed by DMV brands your car as having invalid or odometer tampered mileage – usually knocking 1/2 its value off.
Next cold morning – 100% success! Shifting problem fixed. In fact, it shifts more cleanly in everyday driving too. Who would have thought a speed cluster would cause a shifting problem. Live and learn. Now to get out and make sure it’s up to snuff.