Those that changed diff/trans fluids to 75-90W

[Casper]

Has anyone experienced what seems to be transmission hunting while after sitting for longer periods in cold temps?

Ever since swapping out the original OEM fluid in the F/R Diffs and Trans Case to 75-90W, I have been running into what appears to be transmission slip when the transmission upshifts after extended sit periods in cold temps. Normally on a 2-3 upshift the tranny will seem to slip reaching upwards of 3K on the tach before quickly settling back down to "normal" rev band activity.

Seems interesting since it would appear to be more of a tranny issue than anything else but the original fill OEM tranny fluild has not been changed thus far.

 

[jacal]

no issues for me, and it has been -25C here for quite a few days.

J

 

[OUTRNNR]

That sounds like your torque converter isn't locking up. My guess is that only the fluid used in that would have an effect. Not fluid in the difs...

 

[Kmvreter]

no issues for me, and it has been -25C here for quite a few days.

J

Ditto. When you say cold, how cold is it in Vegas?
Could be coincidence on the timing of your concern relative to the fluid change. I went to synthetic gear oil and if anything it should help in the cold because of the lower pour point. The gears should turn slightly easier before things warm up (this is all relative.)
Is the tranny actually "slipping" or is the shift point just at a higher rpm? My shift points change in the winter depending on engine temp (forcing the engine to rev higher for longer to get up to working temp faster; this is normal.)
If the tranny is acting up in the "cold" I say take it in for warranty. Make sure you drive it for the tech so they can't claim "unable to reproduce the symptom."

 

[Casper]

Cold and Vegas are loosely used in terms together.

The tranny is actually slipping. The shift points are changing as when the abnormality occurs the car is shifting at about 2K rpm but when it upshifts, the revs quikly climb to 3K or so before then comming back down to normal 25-30mph territory for 3rd gear.

Thats what i find is interesting as well...that this has only surfaced after having the Diffs/Transfer fuilds switched over and as such cold shifting should improve not get worse.

 

[Kmvreter]

Cold and Vegas are loosely used in terms together...

Thats what i find is interesting as well...that this has only surfaced after having the Diffs/Transfer fuilds switched over and as such cold shifting should improve not get worse.

I agree. Good description. Sounds like it wants to downshift first but then upshifts (as you called it earlier, hunting.) How's the tranny fluid level? If it's OK then it looks like a dealer item. Let us know how you make out.

 

[Koz]

That sounds like your torque converter isn't locking up. My guess is that only the fluid used in that would have an effect. Not fluid in the difs...

:iagree:

Koz

 

[Casper]

was gonna have it looked at yesterday but my cold got worse and today I was swampped with stuff so I could leave on some vacation before my holiday trips come up.

Ill take it in on tuesday of next week.

 

[Kmvreter]

Casper,
Any follow-up as to what was found?

 

[khaug]

Has anyone experienced what seems to be transmission hunting while after sitting for longer periods in cold temps?

Ever since swapping out the original OEM fluid in the F/R Diffs and Trans Case to 75-90W, I have been running into what appears to be transmission slip when the transmission upshifts after extended sit periods in cold temps. Normally on a 2-3 upshift the tranny will seem to slip reaching upwards of 3K on the tach before quickly settling back down to "normal" rev band activity.

Seems interesting since it would appear to be more of a tranny issue than anything else but the original fill OEM tranny fluild has not been changed thus far.

Hard to understand how changing the transfer case/diff lube could affect your A/T shifting! I changed ours @ about 30K miles to Mobil 1 75w-90, with no change in tranny performance.

Our 'Runner still has the original ATF in it @ 60K miles (yeah, I know, shame on me!), and all is just fine. If I were you, I'd check the ATF level as a starting point.

IMO, the tranny issue is something independent of the diff/TC lube. Please let us know what you find.