I have a 87 Bronco II, 4x4 5 speed (FM145) I recently changed the tranny fluid with 80-90 as recommended by NAPA and then started to get grinding noises in 1st, 2nd and 5th gears (very loud in 5th) My transmission shop suggested that I use synthic 5-30 motor oil but this just made the noised louder, they also said that I could use Dexron III. My manual says to use 80 weight but I can't find anyone who sells it. I replaced the clutch about 1500 miles ago and the transmission was rebuilt around 40,000 miles ago. Does anyone have any suggestions for me?

 

I would first reccomend that you consult your owner's manual, a factory service manual, or your local Ford dealer for the reccomended fluid to use in your transmission. I have heard of cases in wich using the wrong fluid (80/90 gear lube) in place of ATF can cause unusual noises and binding and it sometimes takes a disassembly, cleaning or more to correct the issue.

 

Mr Mopar is correct. I had the clutch replaced in my truck and the person who replaced it put 80 wt. in my tranny. Long story made short. I burned up. It should of had ATF (automatic transmission fluid) in it. Yes it was a manual transmission. Make sure which yours needs.

 

sounds like its time to rebuild the tranny.

 

For BII with Mitsubishi owners manual tell to use 80W - I put 75W-90 synthetic (it's better than 80W), but I'm not glad what my trans work with it...

 

the 80W gear oil has a motorcraft part number. look in the owners manual for the part number then order a few quarts from a ford dealer. if you can not find it in the manual just call a jiffy lube or better yet a "Valvoline instant oil change" and ask them to look it up for ya. it is easily found there. I run one of the valvolines myself if i had my shop PC i would give ya the part number myself. also another suggestion i do myself.... get "WYNNS" brand friction additive and put it in all gearboxes. the stuff is like liquid gold!!

 

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Not that I am a big fan of Walmart, but I got my 80 wt oil in the one quart bottle with the pointy end in their brand and the castrol from them. You might check there...

 

I'd be willing to bet that the fluid you should have put in was ATF, and not 80wght. gear lube.

 

dlink here is what I found about the FM 145

Note: Only the Mazda M5OD-R1 uses ATF. This transmission was put into use in 88 behind all engines, EXCEPT for the 2.9. All pre 88 transmissions and ALL 2.9 transmissions use gear oil. These transmissions are the TK-4, TK-5 and the Mitsubishi FM-145, FM-146, and FM-132

So gear oil is the choice.

 

Well I guess stand corrected,,My 91 ranger has the Mazda, 4spd OD, which does use ATF.

 

First question is did you change the throw out bearing and pilot bearing when you did the clutch and did you grease the pilot bearing. If not one or both will do it and can damage the input shaft bearing. If the owners manual calls for 80w then 80w 90n is fine. Tell the trans shop they can assist in paying for the rebuild. My 86 with the 5 speed uses ATF. Once a year dump and flush.

 

the correct fluid is motorcraft part number XT-M5-QS from what i can find in spec books. I highly reccomend using that. if ya cant get it or dont have a local ford place I plan on ordering royal purple straight 80 from JEGS. this is actually better than a synthetic 75-90, (even though both are synthetic) and is a lil expensive though. something like $8 - $9 per quart