[65fbmustang]

I have a 4spd top-loader behind a mellow 289. The car leads a very casual life now as a driver/cruiser--it doesn't have enough juice left to race anyone, but runs smooth. The miles on the trans are a mystery--potentially more than 180,000.

I checked the fluid and it was very low, so I pumped out the old fluid and replaced it w/ the same fluid I used in the rear-end--85w145 hypoid limited slip gear oil that was recommended by the local rod parts guys. The old-timers in there usually know their stuff, but after changing the old trans fluid w/ this new stuff, the tranny is incredibly stiff, and refuses to go into first w/o a throttle blip and a bit of force, then it thuds into gear. Prior to the fluid change, the tranny would fall into gear w/o any effort. Other than fluid, there hasn't been any change. The weather has been rather cold--near freezing at night.

Will this fluid get better w/ some wear, or is it completely incorrect?

 

[302 Z28]

Sounds as if you got the wrong fluid in it. The weight sounds too high to me. What year is the trans? Call the local Ford dealer in your area and see what they recommend.

Vince

 

[woodz428]

I agree, if you didn't over fill, it is probably too heavy. I would run an 80/90W in both. The difference between 90 and 145 would definitely make it stiffer.

 

[bud-23]

David Kee is the man.

www.4speedtoploader.com

75/90 wt.

 

[wfo guy]

Becaue it's close to winter, the 145 wt oil is way to thick. The 80-90 is what I used to run in mine. They were still stiff until driven for several miles. There may be better oil now but the oil in the toploader is designed to be a heat absorber. If you were to put in 50 wt. and drive it a long distance, you could suffer from gear failure. Because you think the trans is high mileage, I'd be real careful.