Auto transmission, 83 Suburban: part II

Warren,

To keep her alive, ATF + filter changes every 15K, every 7-8K with towing. Install the biggest aftermarket AT cooler you can fit in FRONT of the radiator and/or condensor and completely bypass the OEM cooler. ATF temps will never be below 195* so long as you're using the OEM radiator/ATF cooler. With a stand-alone cooler you should be seeing temps between 100F and 160F which will vary with ambient air temp.

Doc

Re: " And what else should I do to keep from killing my tranny again? TIA, Warren Santa Rosa de Cop=E1n, Honduras"

*********************************************** Hi Warren. What Doc says above will keep you good for many years. One thing to add ,though it's been decades since I managed a few AAMCO shops,is that AAMCO used to install the aux.cooler in series with the original cooler and before it.I guess that was because ATF is designed to operate at certain temps and that the viscosity is set for this minimun.I personally tend to think that if you use just a stand alone aux. cooler that your tranny would be operating at too low a temp.much of the time and that this MIGHT affect shifts,lock-ups,torgue-converter operation etc. I don't think it makes much difference one way or the other and like I said it's been a long time so things may have changed.I don't know if current manufacturers ,when adding a tranny cooler option, leave the radiator section in play or not.If they do then I would too,assuming the factory engineers must know what they are doing. Since heat IS the tranny enemy #1 ,I'm sure either way will help. Best.......Brian p.s. For this advice all I require is a medium pepperoni ,easy cheese. ******************** There are three kinds of lies; lies,damned lies,and statistics.---Disraeli

The above is assuming your cooling system is operating in perfect condition and will be kept that way. B.

1: He just blew a tranny. Who knows what crap is in that cooler. 2: A tranny heats up it's fluid MUCH faster than your coolant ever will.

I hooked my cooler up bypassing the OEM cooler.

GMC Gremlin

*********************************************** Hi Warren. What Doc says above will keep you good for many years. One thing to add ,though it's been decades since I managed a few AAMCO shops,is that AAMCO used to install the aux.cooler in series with the original cooler and before it.I guess that was because ATF is designed to operate at certain temps and that the viscosity is set for this minimun.I personally tend to think that if you use just a stand alone aux. cooler that your tranny would be operating at too low a temp.much of the time and that this MIGHT affect shifts,lock-ups,torgue-converter operation etc. I don't think it makes much difference one way or the other and like I said it's been a long time so things may have changed.I don't know if current manufacturers ,when adding a tranny cooler option, leave the radiator section in play or not.If they do then I would too,assuming the factory engineers must know what they are doing. Since heat IS the tranny enemy #1 ,I'm sure either way will help. Best.......Brian p.s. For this advice all I require is a medium pepperoni ,easy cheese. ******************** There are three kinds of lies; lies,damned lies,and statistics.---Disraeli

Brian;

There os a VERY GOOD reason for bypassing the in-radiator cooler

Debris left over from the previous disaster

It is sometimes inpossible to remove, even with a 'Hot-Flush' machine like a DCI

So bypassing it makes a lot of sense................and as far as running the transmission 'too cool', it's never been a problem here (western IL), we do it on EVERY 4x4 and every other truck that does anything more than haul a driver back and forth

Really HD units like the 4L80E, Ford E4OD, Mopar A518/618 get a pair of big coolers, plumbed in parallel, and for GM and Fords, a 50-50 mix of ATF and MobilOne 5-20 Synthetic Engine Oil (have to use Mopar ATF +3 or ATF +4 in Mopars due to converter clutch chatter)

*********************************************** Hi Warren. What Doc says above will keep you good for many years. One thing to add ,though it's been decades since I managed a few AAMCO shops,is that AAMCO used to install the aux.cooler in series with the original cooler and before it.I guess that was because ATF is designed to operate at certain temps and that the viscosity is set for this minimun.I personally tend to think that if you use just a stand alone aux. cooler that your tranny would be operating at too low a temp.much of the time and that this MIGHT affect shifts,lock-ups,torgue-converter operation etc. I don't think it makes much difference one way or the other and like I said it's been a long time so things may have changed.I don't know if current manufacturers ,when adding a tranny cooler option, leave the radiator section in play or not.If they do then I would too,assuming the factory engineers must know what they are doing. Since heat IS the tranny enemy #1 ,I'm sure either way will help. Best.......Brian p.s. For this advice all I require is a medium pepperoni ,easy cheese. ******************** There are three kinds of lies; lies,damned lies,and statistics.---Disraeli

How does the syn motor oil help?

GMC Gremlin

great heat-carrying capacity

plus doesn't thin out a much as ATF

Is this procedure only recommended for HD applications?

GMC Gremlin

before I used it on customer's vehicles, we tried it on our own.......84 B-350 Dodge van, 86 Bonneville, 81 Bronco with no ill effects

I've also used it in the Mitsubishi 'KM' series FWD units

My pleasure; I´m making it now. It will be ready for pickup in 15 minutes. Oh, did I mention that you live outside our free delivery area?

Warren Santa Rosa de Copán, Honduras

Okay, I´m on the lookout for aftermarket AT coolers locally.

In the meantime I´m using the OEM cooler and am monitoring the temperature. The transmission temperature is mirroring the radiator temperature, which tells me that the transmission temperature sensor is working properly, the OEM cooler is working properly, and that so far I haven´t pushed the transmission very hard.

Sooner or later I will, however, and the transmission temperature is going to rise. How hot can I safely run it? Granted, cooler is better, and that´s why I´m looking for an aftermarket cooler. But in the meantime I don´t want to cook anything.

TIA, Warren

how are you measuring it ?

if you are using an aftermarket gauge, fine...but a lot of times the scan-tool 'Transmission Temperature' is simply the radaitor temperature

which tells me that the transmission temperature sensor is

We scanvenged a known good ATF temperature sensor and it´s dashboard gague from a bus transmission and adapted it to my tranny. The sensor is mounted on the transmission and is reading the ATF temperature there.

Warren