Transmission temp gauge sender..where to install?

[Brian894x4]

I'm thinking about adding a transmission temp gauge this weekend. The problem is I can't figure out where to put the sender. I've got a '95 FZJ80.

Do any of you have a set up like this and where did you install the trans gauge sending unit?

Any ideas would be appreciated.

 

[Brian894x4]

Found the drain pan thread size from this post:

http://forum.ih8mud.com/80-series-te...eads-97-a.html

At least for '95-97 its M10x1.5.....that's some good info there. Since I can get a sender to fit that, I may just go that route. If a weld in bung is recommended in the pan, then the temp reading should be the same using the drain plug instead.

Anyone think of a reason not to go this route? It sort of limits my gauge options as only VDO and maybe a few others makes a sender in that size, but its doable.

And it should be very quick and easy to get a trans gauge up and running.

 

[ntsqd]

This is one of those cans of worms topics. There are many who say the sender should be in the cooler lines. Some want it in the return, but most want it in the supply. Their idea being that they'll see if the converter flash-heats the fluid to an exceptional temperature. I don't think the odds of actually witnessing that flash are very good.

I think your idea of it being in the pan is best, and a large builder of GM late model trans thinks so too as that is where they want the sender located for the gauge sent with each trans. That is the fluid that the trans is drawing from, so that is the temp that is critical as far as I'm concerned.

My preferred install method is beyond the average garage fabricator's tools, but I'll mention it for reference or consideration. I buy an NPT nipple from McMaster and lathe a step in the end to be welded to the pan. The OD of the step is some easy size found on a Unibit (ideal for drilling sheet metal) and the width of the step is equal to the pan's thickness. I use three healthy TIG tack welds around the OD of the nipple, and then use a continuous bead of Silicon-Bronze around the parting line on the inside using only just barely enough heat to get the filler to 'wet-out' & flow. I even push it around a bit with the torch rather than use more heat.

 

[RAM5500 CAMPERTHING]

We installed one in our race truck (93FZJ80) and unfortunately do not have any pics.

We installed it in the cooler lines (supply) to give a more accurate reading then after the oil passes through the cooler (return).

All our our lines were custom, going to a huge cooler in the rear and the sending unit setup was mounted under the rig with a little skidplate we built for it!

We machined a block of aluminum (very similiar to the OBA manifolds a lot of folks are using) for a manifold and used AN fittings to connect everything up!

Thinking of it, you could probably very easily use one of those manifolds!

Wasnt the "cleanest" install, but i assure you, it was the most bomb proof!

Looked really funny too as we used it from a block of Alum i had laying on my garage floor that was like 5"x5"x7" super huge for the little thing that it was!

Worked awesome!

 

[Brian894x4]

Interesting info. Thanks for sharing.

I've spent hours searching the net, including all over mud for any bit of information I could come up with. There are a few threads, but most lack any detail.

It's most frustrating when people say they've installed a tranny gauge and absolutely no detail, not even brand of gauge. But then there's a few that have kinds of details on how to wire up a gauge, but not even a hint about where the sender went.

I mean, most of use can figure out how to wire a positive, ground and light wire. It's the sender that's the tricky part here.

So, welding bung is not going to happen. Although it would probably solve a lot of problems.

Building a T-fitting and splicing into the output line to the cooler seems like a more common option, but I definately don't want to cut hard pipe, and I'm not sure of a good place on the 80 to try ti mount this set up. Plus there's a lot more parts to source.

The drain plug is M10x1.5. A sender that would fit the drain plut would be a cinch to install. The problem is, so far VDO is the only manufacture that makes that size sender and it's only for their 150-400 degree trans gauge, which is way out the useful range to me.

If the lower temp range oil temp gauge could work with that same sendor, it's an alternative, but not a whole lot better.

I'd really prefer a digital gauge with a very wide range, like Autometer's 0-300 range gauge. But the sending unit is 1/8 NTP. Which gets me back to something like a customer T fitting.

Someone suggested a thermo sensor based gauge and mounted the sensor on the outside the (probably) outgoing line. That sure sounds nice. Anyone know such a product that can be sourced fairly easily? I'm not having trouble locating one.

Or any other ideas?

 

[cruiser guy]

I don't have an automatic tranny so my opinion is what I would do IF I had one.

For me, I want to know what is going on inside the tranny and probably the best place for that is right at the tranny where the fluid goes to the cooler. I'd find a "T" fitting and adapt the temperature probe to fit there. I think that the pan would have oil that is alot cooler than internally in the tranny due to the radiant dispersion of heat from the pan.

You'll find hydraulic hose dealers have a very wide variety of brass fittings and that is probably your best source for those kind of parts.

I don't know how fast the tranny temp gauge responds but the pyrometer for my turbo responds as fast as I'd be able to react and take corrective action.

btw. This sounds a lot like the debate that is ongoing in turbo circles. Do you put the pyrometer before or after the turbo?

 

[ntsqd]

snip.....
We installed it in the cooler lines (supply) to give a more accurate reading them after the oil passes through the cooler (return).

More accurate than what?

Keep in mind that the trans pan is a volume of fluid and that not all of the fluid in the pan went thru the cooler on it's last trip through the transmission. Some of it dripped down out of the transmission's various bearings & clutches. So the temp of the fluid in the return line is not indicative of what the temp of the fluid in the pan is. The fluid in the pan will nearly always be hotter.

Another thing to be aware of is cooler line restriction. The pressure in cooler lines is typically about 15-20 psi. At that pressure it doesn't take much to significantly block the flow of the fluid. Most 'T' fittings when "filled" with a temp sensor do not have a lot of fluid flow room left over. Another thing to be careful with is the orientation of the 'T'. If it is placed with the sensor up then there is a pocket where an air bubble can stay and never get bled out of the cooler lines. That air bubble will act to insulate the sensor from the fluid. Eventually the air temp will equal that of the fluid, but there will always be a delay (hysteresis). Placing the sensor down or something below horizontal makes the system self-bleeding of air. (FWIW this sort of thing is a daily aspect of my job.)

If all that you're concerned with is how hot the torque converter is getting the fluid, then the cooler supply line is probably the best place. I do not care about the fluid, it's not the expensive part of the system. The temp of the fluid being pulled into the trans is what is most important to me since that affects the longevity of the part I care about.

See what I mean about this topic being a can of worms? Most any placement is valid given what you're emphasizing or looking for. I'm looking for maximum lifespan of an expensive part to repair or replace.

Brian, if you decide that you want it in the pan and can either do without the pan long enough for it to make the FedEx round trip, or can scare up another pan I'll offer to weld in the bung.

[hijack]The temp of the turbine wheel and blades is crucial to the lifespan of the part and of the turbo. There is no question in my mind that the EGT t-couple should be immediately ahead of the turbo. We have long ago discontinued using the downstream EGT t-couple on the turbo test stand as it told us very little that was useful. This is also something I deal with almost daily at work (we don't test every day).[/hijack]

 

[Grim Reaper]

I have run Hayden's I picked up a Pep Girls on my last two GM's. The adapter happens to come apart and fits the drain plug on my Chevy's engine oil pan. It came with a bung adaptor for installing it in the transmission (GM's don't have drain plugs) and will function as a drain plug. I ran both senders to a micro switch so the single gage can look at either the engine oil temp or the transmission.

Personally I want to see the temp of the oil in the pan AFTER its been heated by the transmission. I figure if the oil in the pan is still close to a reasonable temp then the transmission should be doing OK.

The short of it is you might be able to get and adapter and size down and open up more possibilities for who to get this from if you don't want to drop the pan to install a fitting.

The gage I have is on the top of page 67 on this PDF model 275. It shows the adaptor set up that comes with it or separate and its model 270. The sender is very close to the same size as the sender for the gage in a 22R.
http://www.haydenauto.com/catalogs/hayden/2007-hayden-trans-oil-coolers.pdf

 

[Brian894x4]

Well,

I'm trying to keep this simple, but I'm really limited in my options.

At this point, I don't really want to cut into the cooling lines and I don't really want to drill and put a sensor in a new hole in the pan. Which basically leaves two options.

An outside thermosensor attached to some stratigic location or a sensor in place of the drain plug.

The problem with an outside thermosensor is I don't think they would be very accurate, but it would be an easy install once the parts were found.

I'd much prefer the drain plug sensor, but finding out what the threads are for this stupid plug has been an ordeal. I have one source indicating M10x1.5 and another indicationg M12x1.25.

There's only one sensor on the entire planet that I can find that is made in the M10x1.5 and that's a VDO trans sensor, for their gauge. I haven't been able to locate one locally, but this one is probably one of the better options, except for being limited in gauges. I don't like the VDO's limited range.

If drain plug is really M12x1.25, that opens up some wider possibilities and there are more sensors made for that size. I do know that size is the standard oil pan drain for "most" Toyotas, which is probably why more sensors are made in that size.

The M10x1.5 is a very oddball size and very rare, although it may be the standard Toyota transmission drain plug size.

 

[ntsqd]

FWIW I looked at the possibility of drilling the M10 plug to have an 1/8NPT hole in it's center and it won't work. The through-hole size is too big. Could possibly do this with an M12, it's close. A thick headed bolt combined with shallow tapping of the NPT hole would work.

What is the possibility of opening up the drain to the M12 size? Is there room in the pan for that?

 

[spressomon]

FYI: The ScanGuage II will also display tranny temps (OBD11)...I don't know where it gets the temp...but maybe an option for you.

I've got one but haven't set it up/connected it permanently to the dash yet.

http://www.scangauge.com/features/

 

[MoGas]

I would put it as close to the factory sensor as possible because that is where the engineers felt it was most critical to monitor the temp from. Since you have a 95, and OBDII, you may be able to monitor the tranny temp via a scangauge.

 

[Brian894x4]

FYI: The ScanGuage II will also display tranny temps (OBD11)...I don't know where it gets the temp...but maybe an option for you.

I've got one but haven't set it up/connected it permanently to the dash yet.

http://www.scangauge.com/features/

I do have the latest scangauge a with X-gauge, no tranny temp option, because scangauge doesn't have the code to pull that off. They've tried, but they need proprietary information that they can't seem to get from Toyota since it's a non-standard OBD sensor. Otherwise, the scangauge is awesome for other things like engine temp, and many other sensors. Very cool product!

Regarding the drilling out the drain plug, I think if I was going to go that far, I'd probably just drill and weld in a new bung to the pan.

What I've settled on now, is that I finally located a place locally that carrys the only temp sensor in the world that is same threads as our tranny plug. It's a VDO 400F sensor for transmissions, but its pretty rare. Very few people carry it.

This should plug right into the pan, no mods necessary. However, the specific gauge its meant for is a VDO trans gauge with a range of around 150-400F, which is rediculously outside the range of our transmissions, which typically operate in the low to mid 100 degree range.

So, I'm going to attempt to mate it with a 100-250 degree VDO water temp gauge. Both gauges use 10-180 ohm sensors, so I'm hoping it will work.

Only one way to find out.

 

[spressomon]

I do have the latest scangauge a with X-gauge, no tranny temp option, because scangauge doesn't have the code to pull that off. They've tried, but they need proprietary information that they can't seem to get from Toyota since it's a non-standard OBD sensor. Otherwise, the scangauge is awesome for other things like engine temp, and many other sensors. Very cool product!

Regarding the drilling out the drain plug, I think if I was going to go that far, I'd probably just drill and weld in a new bung to the pan.

What I've settled on now, is that I finally located a place locally that carrys the only temp sensor in the world that is same threads as our tranny plug. It's a VDO 400F sensor for transmissions, but its pretty rare. Very few people carry it.

This should plug right into the pan, no mods necessary. However, the specific gauge its meant for is a VDO trans gauge with a range of around 150-400F, which is rediculously outside the range of our transmissions, which typically operate in the low to mid 100 degree range.

So, I'm going to attempt to mate it with a 100-250 degree VDO water temp gauge. Both gauges use 10-180 ohm sensors, so I'm hoping it will work.

Only one way to find out.

Thanks for the clarification Brian. The instructions that came with it stated to download the appropriate file...hadn't gotten around to even checking the compatibility. Bummer.

 

[Grim Reaper]

I do have the latest scangauge a with X-gauge, no tranny temp option, because scangauge doesn't have the code to pull that off. They've tried, but they need proprietary information that they can't seem to get from Toyota since it's a non-standard OBD sensor. Otherwise, the scangauge is awesome for other things like engine temp, and many other sensors. Very cool product!

Regarding the drilling out the drain plug, I think if I was going to go that far, I'd probably just drill and weld in a new bung to the pan.

What I've settled on now, is that I finally located a place locally that carrys the only temp sensor in the world that is same threads as our tranny plug. It's a VDO 400F sensor for transmissions, but its pretty rare. Very few people carry it.

This should plug right into the pan, no mods necessary. However, the specific gauge its meant for is a VDO trans gauge with a range of around 150-400F, which is rediculously outside the range of our transmissions, which typically operate in the low to mid 100 degree range.

So, I'm going to attempt to mate it with a 100-250 degree VDO water temp gauge. Both gauges use 10-180 ohm sensors, so I'm hoping it will work.

Only one way to find out.

Transmissions run around 180-200. Never seen a auto run less then that. Even with big coolers I never got one to run below 170 on the hwy.

That's the target heat range for the fluid. If the cooler is factory in the radiator it is going to run nearly the same as engine temp.