MUA5 Oil

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MUA5 Oil

Postby dankly1 » Thu Mar 11, 2021 3:05 am

Hello all. 93 Pickup 4X4 4ZE1 MUA5

I changed the oil in the transmission and transfer case a couple of weeks ago after having the truck for around a month. This is what I used:

Trans - Rotella 15W40 semi-synthetic
Transfer - Mobil 1 5W30 Synthetic

Since then, it has been much harder to get it to shift into 1st and 2nd. The shifts weren't sliky smooth before, but they are much worse now. Obviously, I need to change to a different oil in the trans. What do you all recommend? Maybe some fancy AmsOil or something?

Thanks!
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Re: MUA5 Oil

Postby gruff54 » Thu Mar 11, 2021 7:45 am

I've been needing to change mine. Several have recommended a manual transmission specific oil, supposedly it doesn't break down in a transmission like regular motor oil. I've seen Royal Purple recommended,saying it improved shifting, but it's expensive. I did look for an alternative transmission specific oil, but nothing stood out. I did ask Jerry what he'd recommend. He said he uses Rotella 5-40, but if I did use a transmission specific oil, to make sure it was the proper viscosity. Ernie told me when I bought it I'd have to shift like an old man, but that's OK 'cuz I am. :lol: . I'll probably go ahead and try the Rotella as I already have a jug here.

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Last edited by gruff54 on Thu Mar 11, 2021 9:40 pm, edited 3 times in total.
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Re: MUA5 Oil

Postby 93trooperpooper » Thu Mar 11, 2021 9:03 am

maybe look into Pennzoil synchromesh oil....i use that in my suzuki 5 spd transmissions. actually cured some grinding shifts in on of my 5 speeds...protects like a 75 w oil, but pours like a 5 w oil at -40f. not the cheapest either, but it works for me !
will drive these until they quit and move onto something else.
parts from JERRY LEMOND.
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Re: MUA5 Oil

Postby gruff54 » Thu Mar 11, 2021 9:23 am

93,
I saw the Pennzoil in my searches, but it didn't list the viscosity. Do you happen to know what it is? Thanks.

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Re: MUA5 Oil

Postby geoffinbc » Thu Mar 11, 2021 3:17 pm

Run a 5W30 or 0w30. Any 15W oil is way too thick when cold. It would also be advisable to use one of the Zinc rich oils. My personal recommendation is Red Line but anything that suggest it be used on flat tappet cams should be good.
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Re: MUA5 Oil

Postby CharlieK92004 » Thu Mar 11, 2021 4:32 pm

A good rule of thumb for viscosity is, go with what you use in your engine. If you live in the south you can run 15w40,most other places not. The book calls for 5w30, so that's always a safe bet. Personally I use Rotella 5w40 synthetic diesel. It has more anti wear additives than gasoline version.
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Re: MUA5 Oil

Postby gruff54 » Thu Mar 11, 2021 9:43 pm

Just went back and reread Jerry's email. He specified 5-40 Rotella, not 15-40 that I had originally posted. Sorry for the confusion.

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Re: MUA5 Oil

Postby BoiseTrooper » Tue May 04, 2021 9:37 pm

I am getting ready to switch mine out in the next day or so. Right now is has castrol sae 30 basic oil.

I am going to give the Amsoil MTF Synchromesh fluid a try. It is a 5w30 weight viscosity fluid. Currently it shifts fine, but the 1-2 shift is notchier than the other gears.

I will report back with an update as to any differences noticed.

Cheers!
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Re: MUA5 Oil

Postby Jake.Werecat » Wed May 05, 2021 6:51 am

I am happily using 5W30 Mobil 8100 engine oil in my MUA-5 tranny and t-case. Smooth shifting, and no issues so for the last 5 years.
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Re: MUA5 Oil

Postby BoiseTrooper » Thu May 06, 2021 4:44 pm

Reporting back and I am happy.

It is noticeably smoother and the notch in 1-2 shift is minimized if not gone.
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