Tranny slip

[NeXtras]

Recently my transmission has been slipping... i know most of you will say check/change fluid.. i just changed it 3k ago, used MercV.. i dont know if its the MercV causing it... it slips between 1st and second badddd feels like im in neutral until it SLAMS into gear, revs to like 2k rpm...

could this be electrical? if i shut the truck off for about 5 minutes it will stop.. doesnt seem related to operating temp either..

ive heard it could be speed sensor.. but its slipping bad enough that i can smell the clutches burning..

any ideas?

 

[Skandocious]

Recently my transmission has been slipping... i know most of you will say check/change fluid.. i just changed it 3k ago, used MercV.. i dont know if its the MercV causing it... it slips between 1st and second badddd feels like im in neutral until it SLAMS into gear, revs to like 2k rpm...

could this be electrical? if i shut the truck off for about 5 minutes it will stop.. doesnt seem related to operating temp either..

ive heard it could be speed sensor.. but its slipping bad enough that i can smell the clutches burning..

any ideas?

This sounds familiar... Wasn't I the one that said don't use merc V because it has friction modifiers and will cause merc III trans' to slip?

My FIRST action would be to change that fluid back out for III. If she was working good before the change, and you don't have any codes for other things, I think the fluid is the culprit. Do it before you wear out your torque converter clutch plates or you'll be in biiiig trouble.

 

[NeXtras]

i KNEW you would be the first to reply wen u see my name and tranny issues LMAO..

my only argument tho, wouldnt it do it all the time if fluid was the culprit?

i plan to change the fluid again regarless

 

[john112deere]

ive heard it could be speed sensor..

If memory serves correctly (no guarantees, I have no first-hand experience) your speedometer won't work right, either, if it's the speed sensor. And I kind of think they don't so much "slip" as shift at the wrong time...but again, no first-hand experience.

 

[Skandocious]

Ian's absolutely correct, speed sensor would cause erradic readings on the speedo and possibly strange shifts, but no slipping.

And with an electronically controlled transmission it's very possible that it would only do it sometimes. The merc v has friction modifiers that'll cause the tc to slip at times when it's not expecting it, and who knows what the computer will do to try and compensate. I can almost guarantee the fluid is the problem.

 

[surewhynot]

don't use merc V because it has friction modifiers a

I don't mean to nit pick here, but all tranny fluid has friction modifiers. Different fluids have different types, but they all have some.

 

[Skandocious]

Dangit. Haven't we already had this discussion? LOL

Point is-- the merc V fluid has ADDED friction modifiers that don't jive well with merc III transmissions.

 

[surewhynot]

I know what you meant. I just wanted to clarify for others.

 

[NeXtras]

i had a weird issue too where it would shift late to 2nd, a second after it went to 2nd gear, it shifted to 3rd and boggeed

 

[Brian_B]

Do they still have a modulator valve? Those cause this issue and are about $20 to fix.

I doubt they do in 94. LOL

I am not fond of the later solenoid controlled stuff because of cost.

 

[Skandocious]

Not sure what a modulator valve is but these transmissions are in fact the type you mentioned, controlled by electronically controlled fluid solenoids.

 

[Brian_B]

Thought so. Had to ask.

 

[NeXtras]

so the first step ill tak is change the fluid back to Merc III

 

[95F350XL]

Yup. Get some good ATF

 

[flareside_thunder]

The modulator valve is a vacuum engaged valve used to kick the older trucks with C-6's into reverse and can cause similar symptoms.

 

[NeXtras]

Is there any aftermarket fluid that someone would reccomend? if not im going with Motorcraft Mercon III

 

[tomtoc]

i used Valvoline and haven't had any problems. if i was going to do it again, for a little more money on such an expensive part, i'd do royal purpe.

no need to start a royal purple debate, just personal opinion

 

[SuperCab]

I think you should give up and let me have your truck

lmao


Seriously though, fluid can make a big difference.

 

[95F350XL]

For future refrence B&M isnt for electronic trans. I used Penzoil. Works good, no complaints.

 

[Skandocious]

For future refrence B&M isnt for electronic trans. I used Penzoil. Works good, no complaints.

Talkin bout Trick Shift? Yeah, not to be used in electronic transmissions.