Hey all,

So lately my transmission has been slipping ( atleast i think its the tranny ) whenever i come to a stop and try to go. If i apply the brakes hard or even just apply normal pressure to come to a stop then when i go to take off again its like its in neutral then catches itself and starts going again. this mainly happens when i brake harder then normal but has been becoming more and more constant even under normal. My fluid levels seem normal, after a drive i go in park and check the dipstick and its in the full range. I was considering doing a fluid change ( draining the pan and TC ) and refilling everything as well as a new filter. My question is ive read a few times that on these older trucks after doing a fluid change on the trans and putting new stuff in it the trans can stop working like the old fluid was basically holding everything together. Ive only had this truck for about 8 months now and done alot of repairs on it, trans and diff are the only two things i have yet to do a change on. Is it possible or how high is the chance of after changing the fluid of the trans not working anymore or becoming worse then it is now? Once it kicks back in after taking off it shifts fine and downshifts fine. Does this sound like a slipping issue or another possible issue like maybe the differential slipping? Im no expert but im learning at a fast pace as i go.
( Also the fluid to change the trans would be Mercon V right? )

Thanks for any help

Transmission - 4R70W 4 speed auto + overdrive
8.8" 3.08:1 Open Differential
1995 F150 5.0 302 XLT
203k Miles

 

Is the engine running when your checking it? If not, then the level on the dipstick is meaningless.

Old fluid holding everything together is a myth. It can't happen.

What DOES happen is that transmissions are usually ignored. When something goes wrong because the fluid was never changed things happen like the trans goes to neutral at stops. Then the fluid is changed and the trans dies. What they don't realize is that the trans was damaged by not changing the fluid. It was going to die if the old fluid stayed in there. The new fluid didn't cause the failure. It also wasn't able to prevent the failure.

I'm guessing it is likely it will be worse after changing the fluid. I also predict it is going to get worse if you don't change the fluid. The only way this isn't going to be terminal is if the fluid level it quite a bit low.

A differential can only slip one time. The only way it can slip is when teeth are broken off the gears. Once they break off they don't put themselves back on.

Right.

No, it is not a four speed plus overdrive. It has four total ratios, and one of those is overdrive.

 

Gotcha, the PO hardly did anything to this truck and was in rough shape when i got it. Oil was hardly changed trans fluid i have no clue when was changed, its not black or anything, its still somewhat reddish color so it has been changed at some point but no clue when. I plan on getting a new ford truck at somepoint soon before snow fall thats 4x4 as trying to drive a 2wd open diff in ohio snow would be a nightmare. Once that happens i will hardly use this truck anymore. would you recommend changing the trans fluid or just holding out till i get a new truck in a few months. I cant afford a new transmission for this one so if a new fluid change does this one over im kinda screwed. Yes the engine was on as well when i checked the dipstick. You said it will get worse after a change most likely yet get worse if i dont change it. would you risk changing it or leaving it ( if you were to only drive it for another month or two )

Thanks

 

What he meant is it's gonna get worse whether you change it or not. New fluid will not speed up nor slow down the getting-worse process.

If you're getting a new truck then just leave the old fluid in it. When you sell it just list it as needing a transmission rebuild.

 

What I was getting at is that your transmission has a mechanical failure inside. Whether or not you change the fluid this transmission isn't going to last a lot longer. At this point I think changing the fluid is a waste of money.

 

Gotcha, thanks guys. At this point ill just leave it i guess, maybe a slip additive may help i can throw in, guess it will just be a beater or work truck once i get a new one