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1990 gmc 5 speed trans


tygar663's Avatar
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05-16-04, 08:59 AM   #1  
tygar663
1990 gmc 5 speed trans

need to know what fluid goes into the trans its not gear lube it looks like atf
help the book says manual trans fluid but auto parts guy has no idea

 
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05-16-04, 09:53 AM   #2  
Should be DexronII ATF. Have you checked your owners manual?

 
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05-16-04, 03:09 PM   #3  
It depends on the trans you have. What truck and engine do you have? Some take 80w90 and others take Synchromesh.
Hope this is helpful to ya,
Billy

 
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05-16-04, 07:52 PM   #4  
tygar663
thanks it was dexron II atf fluid. anyway the truck is up and running with the new 5.0 in it have a few small issues but nothing major. big diffrence from the tired old 4.3 lots of modifications and hunting in the old junk yardsit goes in tomorrow for the dual exhaust

 
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05-17-04, 03:40 AM   #5  
Actually it should be Synchromesh if you have a Muncie 5LM60 (HM290) transmission.Synchromesh has totally different friction qualities than Dexron. If you had an automatic (4L60 or TH400) then you would use Dexron, or if it were a T5, but not in the larger truck manuals.
Billy

EDIT.......
Since your truck "was" a 4.3 previously then you could possibly have a T5 in there in which case the correct fluid IS Dexron, but you never said that so......

 
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05-20-04, 01:03 PM   #6  
tygar663
it was from the 4.3 it is now a 5.0. it was not gear lube it looked like atf when i drain it. its a 1500 series truck 4 speed with over drive. is there markings on the tranny to tell what it is i want to change the fluid in it anyway just incase some moisture got in there while it was out. i want to put the right stuff in there so please let me know how i can tell

 
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05-20-04, 06:08 PM   #7  
If it was original in the truck, you can call your local GM dealer with the vin number or the label information in the dash box and they can tell you exactly every option on your vehicle when it was built.
Hope this helps ya,
Billy

 
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