Manual transmission no drain plug

[Msabken]

You sir have an NV4500. use only the recommended fluids NOT SYNCHROMESH! The wrong gear lube will murder your synchros in short order. I have been waiting on my rebuild kit for mine for a year!

The original fluid Was Castrol Syntorq which is long gone. GM has a safe gear lube as Dodge. You can get it at the dealers.
My AC Delco fluid has been on back order for almost a year. Do not use GL5 gear lube as is etches yellow metals (brass) synchros. The synchros have carbon fiber linings which is why you need to only use the right goop.

Redline says their MT85 is safe as well. Some sources recommend overfilling the 4 quarts. There are coolers and filters available that can add capacity and drop temperatures that take the place of your PTO cover plates.

O.K. rant over.

The drain plug is the bottom bolt of the PTO plate. Standard fluid capacity is 4 quarts.

Welcome to gmt400.com !

Thank you for the input. I can’t believe it takes so long to get “goop” but glad you told me not to use synchromesh

 

[Frank Enstein]

I couldn't bear the thought of you hurting the trans because I went to bed!

When the fluid gets hot like towing in overdrive the fluid breaks down and the trans eats itself.

There are about 14 million threads online about the NV4500 care and feeding.

If I get the trans fixed and the AC Delco stuff isn't in I will go with the Redline stuff.

Bed now back on Tomorrow afternoon EST

 

[Pinger]

Do not use GL5 gear lube as is etches yellow metals (brass) synchros. The synchros have carbon fiber linings which is why you need to only use the right goop.

Redline says their MT85 is safe as well.

Avoiding GL5 is true for all synchro boxes with yellow metal synchros. GL5 can only be used where steel synchros are fitted.
GL4 should be OK for most synchro 'boxes - but as the 'box in question has carbon fibre surfaces....

OP: Don't forget to remove the fill plug first...

 

[Supercharged111]

Avoiding GL5 is true for all synchro boxes with yellow metal synchros. GL5 can only be used where steel synchros are fitted.
GL4 should be OK for most synchro 'boxes - but as the 'box in question has carbon fibre surfaces....

OP: Don't forget to remove the fill plug first...

What if that yellow metal synchro box has a diff inside of it? I never really got a good straight answer on that back in my Yota days.

 

[Pinger]

What if that yellow metal synchro box has a diff inside of it? I never really got a good straight answer on that back in my Yota days.

You have to trust the OEM's recommendation I think!
GL5 is common for a diff in its own casing despite the likelihood of yellow metal bushings. Why that's OK but synchro cones aren't is anyone's guess. Maybe, synchro cones being there to provide friction makes them more vulnerable? I wouldn't go against OEM's advice in oil selection when there's yellow metals present.
Modern day transaxles are as likely to have ATF in them which doesn't sound great for the diff but some of the bearings are sometimes sealed units with grease. Maybe because the grease can resist the loads better than ATF, maybe to ensure that that fine particles released during running in never enter those bearings - as I've heard suggested.

 

[RichLo]

Yep thats an NV4500, I could tell that from the 1st (of many) pics of that PTO cover, lol

Amsoil sells stuff that specifically calls out NV4500s in their recommended uses:

https://www.amsoil.com/p/manual-transmission-transaxle-gear-lube-75w-90-mtg/?code=MTGQT-EA&gclid=CjwKCAiAgvKQBhBbEiwAaPQw3GvyBN7nSGpaBjkzQY5B5T2C6bK9JxYT_Uc7YWjhTJX1tKiAtfTzzxoCMO8QAvD_BwE

 

[thinger2]

I have a 95 k1500 with 5speed. I assume it is an NV3500. I do know my mechanic had 1 hell of a time with the clutch not engaging. I don’t know if that’s important. Anyways I wanted to change the tranny fluid but I am not finding a drain plug. The plug I am assuming is the fill plug is not the 17mm hex that I am seeing as well. So all I am seeing to possibly drain this trans is 2 plates, 1 on each side with 6-8 bolts. Is there a possibility that Chevy used any different transmissions for the manual 5sp? If not is this common? My uncle bought this truck brand new. I don’t think he ever had it changed out.

From the hard learned lesson archive.
Whatever you find out.
Whenever you have a drain plug and a fill plug on anything.
Trans, differential whatever.
Always always pull the fill plug first.
Just to make sure you can.
Draining all of the fluid first and then finding out you cant refill it really sucks.
I always remember "fill first, drain last"

 

[someotherguy]

Agreed on the drain and fill plug advice, I'll add to it, having sockets that are meant to fit those plugs goes a LONG way towards success. Especially the 3/8" square drive plugs, they cooperate so much better with an actual 3/8" square socket, instead of trying to use a ratchet or extension.

Richard