Manual trans & diff temp sensor locations?

[Matt93SE]

Howdy all..
I don't believe the factory trans includes a temp sensor, so I'm looking to add one just to monitor fluid temps on my race car to determine general fluid lifespan based on track hours and fluid temps, and determine if I need to install a cooler.

I've been digging for something on the interwebs, and pretty much only see gauge kits and whatnot but no *real* info on trans temps and/or possible sensor locations.

My car is strapped in the trailer and it'd be a 3 hours ordeal just to pull it out and get it on jackstands, so I thought I'd ask around before I went through the hassles. anyone else monitored temps and have any recommendations here?

(application is SCCA sprint race car.. minor aero, DOT-R tires, ~280whp.. Max 45 min track sessions. Live in the south, so it's 100F in summer here..)

Thanks

[cactus]

Don't know of anything stock on the gen1 cars. The two transmissions I have looked at didn't have anything for one (both pre-facelift). I was going to use the fill hole with an M18 x 1.5 oil galley plug that has 1/8 NPT in it.

[e21jason]

No oem locations but you can get drain plugs with a 1/8 npt port

[Ohio Enthusiast]

Originally Posted by cactus

I was going to use the fill hole with an M18 x 1.5 oil galley plug that has 1/8 NPT in it.

Is the fill hole submerged in oil? I thought you needed to fill it until it just trickles out of the fill hole, hence there wouldn't be enough oil for the sensor to read. The drain hole sounds more appropriate for this, no?

[cactus]

Originally Posted by Ohio Enthusiast

Is the fill hole submerged in oil? I thought you needed to fill it until it just trickles out of the fill hole, hence there wouldn't be enough oil for the sensor to read. The drain hole sounds more appropriate for this, no?

Wanted to keep the magnet on the drain. Making the assumption that there is enough splash and heat transfer through the case to get a useful number.

[Matt93SE]

So digging this one back up since I haven't logged onto this forum in months and came back on here to ask about trans temps...

So I completed the task by buying some brass adapters from the metric threads to a 1/8" NPT. Then I stuck a temp sensor in the plus and screwed them into the fill plug on both trans and diff. This keeps the magnets on the drain plugs. I would prefer to have the temp from the bottom of the 'sump', but don't want to risk not having a magnet for debris.

Sooooo.. now for the fun.
After a 35 min race on a short track (Hallett) in 65F weather.. Transmission and diff temps slowly rose through the race and eventually levelled off after about 25 min on track.

Temps topped out at 298F for the trans and differential was about 265F.
this was with NEW fluid- Redline MT90 + superlight Shockproof in the trans
Redline 75w90 gear oil in the diff.

What's interesting is that the engine temps came up and stabilized by lap 3 while it took another 20 laps for the trans and diff to stop going up.

Next question is whether I bother with installing trans and diff coolers or not, or just deal with 'frequent' fluid changes. I get about 5-6 race weekends a year, with ~2-3hrs of seat time per weekend. Thus the fluid sees about 15 hours of use and then I change it. I'm thinking based on those change intervals that I might as well not bother with a cooler. That said, the ambient temp at the track was in the low to mid 60s and summer TX weather has ambient temps in the 90s for many of my races.. dilemmas dilemmas dilemmas...

[rice_classic]

Nice data. We wrap our overpipe/frontpipe which greatly helped our trans fluid and added little aluminum heat shields where the exhaust passes by the axle/diff along with greddy cover and that fluid lasts much longer now. Trans fluid OCI went from every weekend to every 3-4 weekends and diff every 5ish and now it can do longer than 45 minute races whereas with no shielding or diff cover I was burning my diff fluid within 45 minutes and spitting it out the breather.

I would be curious to see your temps if you added wrap/shielding. Your trans temp suggests that you should prioritize this.

[Muskoka800]

Originally Posted by Matt93SE

So digging this one back up since I haven't logged onto this forum in months and came back on here to ask about trans temps...

So I completed the task by buying some brass adapters from the metric threads to a 1/8" NPT. Then I stuck a temp sensor in the plus and screwed them into the fill plug on both trans and diff. This keeps the magnets on the drain plugs. I would prefer to have the temp from the bottom of the 'sump', but don't want to risk not having a magnet for debris.

Sooooo.. now for the fun.
After a 35 min race on a short track (Hallett) in 65F weather.. Transmission and diff temps slowly rose through the race and eventually levelled off after about 25 min on track.

Temps topped out at 298F for the trans and differential was about 265F.
this was with NEW fluid- Redline MT90 + superlight Shockproof in the trans
Redline 75w90 gear oil in the diff.

What's interesting is that the engine temps came up and stabilized by lap 3 while it took another 20 laps for the trans and diff to stop going up.

Next question is whether I bother with installing trans and diff coolers or not, or just deal with 'frequent' fluid changes. I get about 5-6 race weekends a year, with ~2-3hrs of seat time per weekend. Thus the fluid sees about 15 hours of use and then I change it. I'm thinking based on those change intervals that I might as well not bother with a cooler. That said, the ambient temp at the track was in the low to mid 60s and summer TX weather has ambient temps in the 90s for many of my races.. dilemmas dilemmas dilemmas...

Have you considered moving the sensor plug down to the drain position for a test? Perhaps the readings would rise faster/higher if the sensor was submerged rather than being marginally above the oil and only splashed. If I recall the plugs are the same size, at least on the diff.

[Matt93SE]

Originally Posted by rice_classic

Nice data. We wrap our overpipe/frontpipe which greatly helped our trans fluid and added little aluminum heat shields where the exhaust passes by the axle/diff along with greddy cover and that fluid lasts much longer now. Trans fluid OCI went from every weekend to every 3-4 weekends and diff every 5ish and now it can do longer than 45 minute races whereas with no shielding or diff cover I was burning my diff fluid within 45 minutes and spitting it out the breather.

I would be curious to see your temps if you added wrap/shielding. Your trans temp suggests that you should prioritize this.

Thanks for the insight. That was kinda the point of the testing-- I had some contingency money to spend at a local shop before end of 2021 and he had the AIM sensors on the shelf, so "hey let's do some science" heh. always better to measure and bring some info to the table vs. just asking questions. now I'm armed with a little data from a single race and I can make adjustments and see how it goes.

Due to life schedule, I only get to do about 3-4 races a year, so fluid typically ages out vs. wears out. (in short, I change it once a year whether it needs it or not!)

But I do plan to add some heat barriers/shielding, just haven't gotten there yet. I have a large sheet of the DEI 'floor and tunnel shield' and also some header wrap laying around.


My more immediately pressing issue is to get the brake cooling back under control. I had a wreck last year that tore all the brake ducts up. I ran the last race without them due to lack of time, but the additional heat used 90% of of pads in a single weekend whereas I used to get 3-4 weekends out of a set.
So Verus Eng/ Velox brake ducts and steering rack limiters are sitting on the shop floor with some new 3" hose. If I get time, I'll put some sort of heat shield on the exhaust around the trans and maybe diff.

Originally Posted by Muskoka800

Have you considered moving the sensor plug down to the drain position for a test? Perhaps the readings would rise faster/higher if the sensor was submerged rather than being marginally above the oil and only splashed. If I recall the plugs are the same size, at least on the diff.

I don't think it'll make much difference in the temps. since the fluid is sitting *juust* beneath the temp sensor in a static setting, that stuff is getting circulated and thrown everywhere inside the case when I'm moving- splashing from the gears and sloshing from the whole sump as I turn and brake. the sensor is thus basically dunked in gear oil every other turn or brake zone so I'm confident I'm getting "good enough" data. not real concerned about the exact +/- 1deg data, but the +/- 20deg that tells me whether the fluid is going to last a while without a cooler or if I need to add some cooling.

Additionally, the metric to NPT adapter thingies are sealed with an o-ring against the case. I don't feel real comfortable putting that at the bottom of the trans and risking losing ALL my fluid if that seal fails, plus losing my tattletale shrapnel magnet.

[Muskoka800]

Originally Posted by Matt93SE

Thanks for the insight. That was kinda the point of the testing-- I had some contingency money to spend at a local shop before end of 2021 and he had the AIM sensors on the shelf, so "hey let's do some science" heh. always better to measure and bring some info to the table vs. just asking questions. now I'm armed with a little data from a single race and I can make adjustments and see how it goes.

Due to life schedule, I only get to do about 3-4 races a year, so fluid typically ages out vs. wears out. (in short, I change it once a year whether it needs it or not!)

But I do plan to add some heat barriers/shielding, just haven't gotten there yet. I have a large sheet of the DEI 'floor and tunnel shield' and also some header wrap laying around.


My more immediately pressing issue is to get the brake cooling back under control. I had a wreck last year that tore all the brake ducts up. I ran the last race without them due to lack of time, but the additional heat used 90% of of pads in a single weekend whereas I used to get 3-4 weekends out of a set.
So Verus Eng/ Velox brake ducts and steering rack limiters are sitting on the shop floor with some new 3" hose. If I get time, I'll put some sort of heat shield on the exhaust around the trans and maybe diff.



I don't think it'll make much difference in the temps. since the fluid is sitting *juust* beneath the temp sensor in a static setting, that stuff is getting circulated and thrown everywhere inside the case when I'm moving- splashing from the gears and sloshing from the whole sump as I turn and brake. the sensor is thus basically dunked in gear oil every other turn or brake zone so I'm confident I'm getting "good enough" data. not real concerned about the exact +/- 1deg data, but the +/- 20deg that tells me whether the fluid is going to last a while without a cooler or if I need to add some cooling.

Additionally, the metric to NPT adapter thingies are sealed with an o-ring against the case. I don't feel real comfortable putting that at the bottom of the trans and risking losing ALL my fluid if that seal fails, plus losing my tattletale shrapnel magnet.

You could also look at an aftermarket high volume diff cover. Most include ports for sensors &/or cooler lines. See eBay for a Cusco knock-off at a more reasonable cost. The Cusco and Greddy offerings are ridiculously priced.
Not sure about options for the tranny.

[DrinkenBRZ]

Originally Posted by rice_classic

Nice data. We wrap our overpipe/frontpipe which greatly helped our trans fluid and added little aluminum heat shields where the exhaust passes by the axle/diff along with greddy cover and that fluid lasts much longer now. Trans fluid OCI went from every weekend to every 3-4 weekends and diff every 5ish and now it can do longer than 45 minute races whereas with no shielding or diff cover I was burning my diff fluid within 45 minutes and spitting it out the breather.

I would be curious to see your temps if you added wrap/shielding. Your trans temp suggests that you should prioritize this.

Rice, you’re still running the Pennzoil Synchromesh too aren’t you? Impressive conventional at those temps and counter intuitive.

[DrinkenBRZ]

Originally Posted by Muskoka800

Have you considered moving the sensor plug down to the drain position for a test? Perhaps the readings would rise faster/higher if the sensor was submerged rather than being marginally above the oil and only splashed. If I recall the plugs are the same size, at least on the diff.

I could be wrong, but I doubt it will change results materially. I’ve tried multiple setups on both my rx8 track rats and get consistent results. My transmission runs cooler than my differential though. Almost reverse of the OP and the same oils.

[rice_classic]

Originally Posted by DrinkenBRZ

Rice, you’re still running the Pennzoil Synchromesh too aren’t you? Impressive conventional at those temps and counter intuitive.

Yeah, it works brilliantly.
My temps are not his temps. PS is good for 150C and since all of our gears are spinning in the same direction (not hypoid) the cSt of it copacetic.