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86 720 Z24 2wd longbed 5spd trans noise?


jonnymcfly

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Hello everyone, looking for a little help.

 

I got a noise i believe coming from my trans thats not present until above 2500 rpm, and noise will remain high for a bit after the rpm drops back down after a 5 second rev. Pressing clutch in or out doesnt change the sound. A smell is present that smells like a brake pad (aka clutch disc) burning. But the clutch doesnt slip. Perhaps its another similar burning smell , like grease heating up and my nose is lying to me ;-) All of this just started out of the blue when starting it on Sunday. No heavy driving recently either. Truck drives good and shifts good.

 

Here is a vid of the sound. If anyone thinks the trans is going south, please advise as this weekend the yards around me are 50% off. I could use some advise on what trucks to look for in hopes of a match. The firewall plate Reads NG720 reads FS5W71B HF37.

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There is somethings you can do from the outside of your transmission and it may fix the problem....

 

First... stop driving it.

 

Second.... check the oil level and top it up if needed!

 

The fill hole is about half way up the driver's side (usually but may be on the oposit side) of the main case. Remove the bung and you should be able to dip the end of your finger in the oil. If not top it up until oil drips out. Use only GL-4 80w90 EP gear oil. In a pinch just use motor oil to get you to a shop  and drain and refill with the correct GL-4.  I just use a kitchen funnel and a couple of feet of garden hose and fill from the engine compartment. 

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you really cant get ur finger to go down. there is a bar in the way. used a zip tie and it goes down about 1\2 inch and hits oil.

 

of course now that I checked it the noise is gone. I seen a post on here about bad carrier bearings and I just don't feel like that's it. no vibration from the stick. trans drives and shifts smooth. strange, very strange.

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you really cant get ur finger to go down. there is a bar in the way. used a zip tie and it goes down about 1\2 inch and hits oil.

 

of course now that I checked it the noise is gone. I seen a post on here about bad carrier bearings and I just don't feel like that's it. no vibration from the stick. trans drives and shifts smooth. strange, very strange.

 

To be clear.... the oil should be level with the fill plug. You shouldn't have to squeeze your finger in and down. If you can touch oil you're fine.

 

 

That VID sounds like the idler pulley for the power steering. Check the power steering oil level. Maybe the clutch fan. Engine off, grab the plastic blades and try to turn them. Loose? or firm to turn?

 

To eliminate the transmission rev the engine with the transmission in neutral and the clutch pedal to the floor. If there is noise it's (at least) not the transmission.

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OK first no power steering on this truck, but man a conversion to it would be awesome.

secondly according to ur theory it is not the trans , cuz that vid was shot in neutral with the clutch both in and out

thirdly the noise suddenly disappeared, I removed the starter looking for ..... well anything. even tested the start and bendix with a battery. also removed the belts and checked all pulleys and nothing strange there either.

lastly vatozone only carries Valvoline and lucas 80/90w that exceeds gl 4 and gl 5. is this ok ?

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Well loosen or remove the fan belt and try it. This will eliminate the alternator and the clutch fan.
 
 
 
 

....as this weekend the yards around me are 50% off. I could use some advise on what trucks to look for in hopes of a match. The firewall plate Reads NG720 reads FS5W71B HF37.

 
 

What is the difference between my trans number above and the trans from an 80 extended cab trans number fs5w71b he33 ?




This is odd as the 3.364 differential is only on the '83-'86 Mileage Option 720 with the Z20 engine. You sure it's an '80? as this would have an L series engine the the transmission is not a direct swap.

 

Assuming it IS a later Z20 powered truck... The trans will work if it's the same length as yours. The only problem (and it may not really matter to you) is this other transmission is a wide ratio box and yours is a mid ratio. This low first gear is to compliment the very low 3.364 differential gearing. You will find that taking off in first the engine revs up quickly and in town it's annoying to have to shift after two or three truck lengths.

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Sorry , my bad , I been at the yards all day and for some reason 80 was stuck in my head. You are right, its an 83 here is the door plate, engine plate, and trans photo

 

http://i296.photobucket.com/albums/mm178/jonroeb/Mobile%20Uploads/20150522_163834_zpsadw6khez.jpg~original

http://i296.photobucket.com/albums/mm178/jonroeb/Mobile%20Uploads/20150522_163818_zpshzjtmthl.jpg~original

http://i296.photobucket.com/albums/mm178/jonroeb/Mobile%20Uploads/20150522_163935_zps0aisdo6z.jpg~original

 

and to answer the other statement , i checked the starter, alternator and waterpump and did run it with all disconnected, but little good as the noise already went away yesterday before testing. Even drove it all day without a starter just in case the noise came back.

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Ya I hear ya, i was thinking the same. But @1/2 off the trans would be $80 and I only found 1 after 3 yard searches. I guess part of me now feels it might be fun to rebuild one and experience how they work. I think I kinda got excited after seeing the animations and photos on this page http://community.ratsun.net/topic/36317-wtb-trans-parts/

 

But you are right .I probabally don't need it. Maybe I have reached the point of looking for and excuse to buy it. I mean after all the syncros in my trans are worn in 3rd gear and Its grinded in a few times.

 

Also its so tempting with the engine already pulled on that truck in the yard. Its like a couple bolts and that trans could easily be mine. But I probabally should save the $85.

 

Btw thank you all for all the info.

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