Transfer case fluid change

[Jeff Newell]

I have a 17 Silverado 1500 z71 that I bought used with 89k miles on it. Around 93k or so, the transmission had to be replaced. It now has almost 100k on it. I know the transfer case fluid is supposed to be changed around this time. 

 

My question is, what are the odds that they changed the transfer case fluid when they replaced the transmission? Or would it not be standard procedure to drop both at the same time. I've searched and have seen mixed opinions. The paperwork did not specify if it was done or not. 

[diyer2]

Well,

I think if the trans had been serviced BEFORE the owners manual recommends(I do more fluid changes) you wouldn't have needed to replace it. So I bet the transfer case was never touched.

[Jeff Newell]

I agree as far as the trans goes. It was a risk of buying a used vehicle. Fortunately I had an extended warranty that covered it, otherwise I would have been real upset. 

 

Just trying to stay up to date with the maintenance now since I can only assume it wasn't fully taken care of before I bought it. 

[rav3]

If it were me, I'd go ahead & change it as it only holds about a quart or 2. Easy job.

[16LT4]

From past used oil analyses, transfer case fluid is due for replacement by 30k miles. Change it. 

[Z45]

I would change it out. I would never trust the shop to be proactive, they likely did only what was necessary and used the lowest cost products in their repair. If you are of the believe all lubes are the same, then drive with confidence. 

Edited July 21, 2023 by elcamino

[newdude]

On 7/17/2023 at 1:57 PM, Jeff Newell said:

I have a 17 Silverado 1500 z71 that I bought used with 89k miles on it. Around 93k or so, the transmission had to be replaced. It now has almost 100k on it. I know the transfer case fluid is supposed to be changed around this time. 

 

My question is, what are the odds that they changed the transfer case fluid when they replaced the transmission? Or would it not be standard procedure to drop both at the same time. I've searched and have seen mixed opinions. The paperwork did not specify if it was done or not. 

 

 

Unlikely.  Transfer case was probably removed with the fluid in it.  Its only 2 quarts in there so not a whole lot of extra weight.  

 

No more than ever 45k miles IMO for transfer case.  The book shows 97,500mi for "normal use" which is insane because the 2500/3500 chart shows every 45,000mi or for severe use every 22,500mi.  

[Jeff Newell]

Yeah. Definitely going to change it. Just hoping no damage has been done. No idea how well it was maintained before I bought it. 

[BigBlue2014]

For good measure, I would suggest replacing Front and rear diff as well as the transfer case. You will already be under the truck with the tools out, so what is an extra 30-45 min of time to have fresh fluid in everything?

[Jeff Newell]

Think I probably will. 

[Wyatt1963]

What’s the best fluid for front, rear differential and for transfer case? For 2015 Sierra 4x4

weight, brand etc..

I don’t get under the truck anymore so what’s a fair shop price for all?

thanks in advance 

[rav3]

I use a synthetic 75W90 limited slip GL5 gear oil in front & rear.  Walmart Super tech works & is a good cost effective  GL5.

Transfer case takes Dexron 6. I use AC Delco  for it but any Dexron 6 meets the spec.

[HoosierZ]

I used Mobil 1 Delvac 75W90 in my diffs because it doesn’t contain limited slip additive. The additive isn’t recommended for the G80 locker. It took 4qts 12oz for both diffs. 
 

[BigBlue2014]

On 7/21/2023 at 7:11 PM, Wyatt1963 said:

What’s the best fluid for front, rear differential and for transfer case? For 2015 Sierra 4x4

weight, brand etc..

I don’t get under the truck anymore so what’s a fair shop price for all?

thanks in advance 

I used Amsoil Severe Gear 75W90 for the Front and rear Diffs in my 2014 and Amsoil Synthetic Trans oil for the transfer case.

[reardiff]

5 hours ago, BigBlue2014 said:

I used Amsoil Severe Gear 75W90 for the Front and rear Diffs in my 2014 and Amsoil Synthetic Trans oil for the transfer case.

 

Same here