Add STP oil treatment to ATF dexron III??

[pablovent]

Hi;

I have autostick superbeetle 1974 (semiautomatic), this system works only with a torque converter and ATF (not 100% automatic trans)......Recently rebuilt engine, everything seems to work fine again after engine work.
For better control, install a pressure gauge in the out atf pump, but I find that the ATF (dexron III) pressure works fine just in cold, after a few minutes to run engine temps appears and the atf pressure low too much, . This suggests that the atf used should be "more viscous" so as not to dilute both with temperature. I think the new atf DEXRON III (or higher) is "less viscous" than the old atf dexron recommended in the manual.
Perhaps it would be best to use thicker ATF for the "old or rebuilt" pumps work better.

The question is whether the system will be "reliable" with a less viscous oil combined an old or just rebuilt pump, especially for long trips in summer ?

My ATF pressure numbers now with new dexron III;
Engine cold temps:
at idle 15 psi
at 2000 rpm 52 psi aprox (perfect, bentley manual)
at 3500 rpm 55 psi max.

to normal temps:
at idle 8 psi
at 2000rpm 38 psi (too low by bentley manual specs).
at 3500 50/55 psi max.(oil relief piston work)

I would try to agree STP oil treatment for increased the viscocity, maybe the numbers with high temps are better!!
Any "better viscocity" ATF type recomendation?



Regards.

 

[turtlevette]

Lucas makes a transmission fix that is very thick like STP. It's designed to work with ATF in an auto trans. I'd recommend that.

 

[Donald]

I would suggest a proper ATF and forget STP or Lucas products.

I would go with Amsoil ATF if its spec'ed for your vehicle.

Do you have a shop manual that lists the transmission PSI? And are you measuring it at the place mentioned in the shop manual?

 

[pablovent]

Pressure gauge installed follow the manual instructions.....in the 1973 manual appear "use dexron with 5-digit number preceded "B" and Normal pressure 52,6 psi at 2000 rpm......My pressure numbers in the last post with dexron III....

 

[Chris142]

If the trans won't work properly with the correct fluid the trans needs work

 

[pablovent]

Originally Posted By: Chris142
If the trans won't work properly with the correct fluid the trans needs work


Old Dexron viscocity = dexron III viscocity specs??

 

[michaelluscher]

Are you using Dex/Merc? Or Dex 6?

You can't buy off the shelf Dex3 anymore

Perhaps try Maxlife ATF?

 

[pablovent]

IMO, for reliable measurement should I use the same manual recommended atf viscosity or another very similar!!

 

[pablovent]

my car needs atf only for torque converter cooler and work....not needs 100% automatic trans specs!!

 

[MolaKule]

Originally Posted By: pablovent
Hi;


The question is whether the system will be "reliable" with a less viscous oil combined an old or just rebuilt pump, especially for long trips in summer ?



Regards.


BAd idea all around.

Oil pressure drops with decrease in viscosity due to heating of tranny fluid.

If pressure is below spec at temp, then you possibly have a leaking oil pump.

 

[pablovent]

Originally Posted By: MolaKule
Originally Posted By: pablovent
Hi;


The question is whether the system will be "reliable" with a less viscous oil combined an old or just rebuilt pump, especially for long trips in summer ?



Regards.


BAd idea all around.



Oil pressure drops with decrease in viscosity due to heating of tranny fluid.

If pressure is below spec at temp, then you possibly have a leaking oil pump.



YES, is not a new oil pump, only sales rebuilted pumps today, my oil pump is rebuilted with new seals and reface plate, then, for increased the pressure is not possible incresed the viscocity at normal temps??

 

[Trav]

Any idea what the original spec was? I had a Citroen CX Pallas with a 3 spd half automatic that took a special hydraulic fluid for the TC but it was labeled as ATF.

 

[pablovent]

Originally Posted By: Trav
Any idea what the original spec was? I had a Citroen CX Pallas with a 3 spd half automatic that took a special hydraulic fluid for the TC but it was labeled as ATF.


in the 1973 bentley manual appear "use dexron with 5-digit number preceded "B"

 

[michaelluscher]

Originally Posted By: Trav
Any idea what the original spec was? I had a Citroen CX Pallas with a 3 spd half automatic that took a special hydraulic fluid for the TC but it was labeled as ATF.


Sure it wasn't LHM? Really bright electric green hydraulic mineral oil used?

From the batteur's of a 2CV, to the hydraulic suspension of a '80s Bentley, its been used quite a bit.

 

[901Memphis]

Redline makes a high temp Dexron ATF, or the Lucas stuff will thicken it up.

 

[pablovent]

Originally Posted By: 901Memphis
Redline makes a high temp Dexron ATF, or the Lucas stuff will thicken it up.


Common atf, type F, is the most viscous atf?.............and yes, read redline specs and aparently is great for me....Lucas is similar?'

 

[pablovent]

Originally Posted By: pablovent
Originally Posted By: 901Memphis
Redline makes a high temp Dexron ATF, or the Lucas stuff will thicken it up.


Common atf, type F, is the most viscous atf?.............and yes, read redline specs and aparently is great for me....Lucas is similar?'


REdline high temps

Vis @ 100°C, cSt 10
Vis @ 40°C, cSt 53.9
Viscosity Index 172
Pour Point, °C -51
Pour Point, °F -60
Brookfield Vis @ -40°C, P 175

mobil type F

Viscosity
cSt @ 40ºC 36.0
cSt @ 100ºC 7.2
cP @ -18ºC (0ºF) 1,600
cP @ -40ºC (-40ºF) 45,000
Viscosity Index, ASTM D 2270 150
Pour Point, ºC, ASTM D 97 -40ºC (-40ºF)
Flash Point, ºC, ASTM D 92 160 (320)
Gravity, API 31.4
Color Red

 

[Trav]

Originally Posted By: michaelluscher
Originally Posted By: Trav
Any idea what the original spec was? I had a Citroen CX Pallas with a 3 spd half automatic that took a special hydraulic fluid for the TC but it was labeled as ATF.


Sure it wasn't LHM? Really bright electric green hydraulic mineral oil used?

From the batteur's of a 2CV, to the hydraulic suspension of a '80s Bentley, its been used quite a bit.


It could well have been. I bought it from the Citroen dealer, this was back in 86 so i couldn't say with certainty what it was or wasn't, it was green though.
The transmission worked well, never any trouble.

 

[901Memphis]

Lucas Transmission fix is super thick, it has a viscosity of 48 cSt @ 100C!

Adding 1 quart of that would thicken up anything pretty substantially.

Adding 1 quart of the Lucas to a 10 quart sump with 9 quarts of ATF with 7.5 cSt @ 100C visc would end up with a final viscosity of approx 8.8 cSt @ 100C.

The results get more dramatic if the sump is smaller. How big is your sump?

 

[pablovent]

Originally Posted By: 901Memphis
Lucas Transmission fix is super thick, it has a viscosity of 48 cSt @ 100C!

Adding 1 quart of that would thicken up anything pretty substantially.

Adding 1 quart of the Lucas to a 10 quart sump with 9 quarts of ATF with 7.5 cSt @ 100C visc would end up with a final viscosity of approx 8.8 cSt @ 100C.

The results get more dramatic if the sump is smaller. How big is your sump?




Complete system use 3.6 Lts (atf tank, Torque Converter , lines).....