What A Great Forum! And A 2-part Newb Question.

[Rancho5]

I recently picked up my 4th Suburban. This one is the nicest (2001 1500 4x4 with 96k) I've ever had and I'm doing fluid changes all around to start fresh.

 

I've changed the oil to Mobil 1 and also drained and filled both differentials with Mobil 1, 75-90w gear oil. Only afterward did I notice in my manual that it recommends 80-90w gear oil (not synthetic) for the front.

 

Will I be alright?

 

Also. Is there any way for me to do a complete tranny fluid change, inc. torque converter, or do professionals have to do that? I'd like to go over the synthetic on that as well.

 

Thoughts or responses?

 

Any input you have would be greatly appreciated. Thanks.

[D&SYukonDenali]

I'd becareful with the tranny change. I'd only do a drain, drop the pan, clean the filter, and fill (no flush). And only use the same fluid that was in it originally. Changing fluid type has an increase probability of causing failures. I would do previous mentioned every 10-15 thousand miles for three intervals and you will slowly replace the old fluid with newer (but the same type) and decrease the chances of failure.

 

Just my $0.02.

[D&SYukonDenali]

For the differentials, I'd research what is considered equivalent fluid (AZ or an auto parts store can help, along with a google search), if you can't find that those two are equivalent and interchangeable, I would change it as soon as possible.

[Rancho5]

For the differentials, I'd research what is considered equivalent fluid (AZ or an auto parts store can help, along with a google search), if you can't find that those two are equivalent and interchangeable, I would change it as soon as possible.

I'll start calling soon. Thanks. I guess I'm a little confused why Mobil 1 75-90w synth wouldn't be equivalent to dino 80-90w. When I drained the front axle the magnetic plug had collected metal dust. I figured the Mobil 1 would help that.

 

For anyone else reading...is Mobil 1 75-90w synthetic interchangeable with dinosaur 80-90w gear oil?

[saxdogg]

My personal theory/opinion (and you know how those are...) is that you'd be fine. The mobil is only available in 75-90 IIRC, and do what you want with the tranny, want to flush, then flush. I'm still not convinced that those flushes are as bad as people make them out to be...

[pennzoil29]

I can't really help you with your questions, but welcome to the forum.

[dietz4ibanez]

Yeah ditto what he said ^^^ Welcome!

[D&SYukonDenali]

Oh yeh, forgot to say welcome!

[fbachman]

I can't really help you with your questions, but welcome to the forum.

 

 

^^^^^^^^^^^^^^ Welcome !

[jrrod2004]

welcome to the forum

[huero626]

Welcome to the forum, any pics of the Suburban?

[Outbacker]

Good questions, unfortunately I do not have the answers, but welcome to the group.

[huskrbill]

Is the differential sealed with silicone or with gaskets? Not sure if GM has changed it but they had a tsb out in the early 90's about use of synthetic with rtv silicone and that the synthetic would cause a leak in a differential sealed with silicone.

[minibike132]

The recommended lubricant for a 8.25 selectable front axle is 80W-90 but for the 8.25 full and all 9.25 front axles the recommended is 75W-90 synthetic. The recommended for the rear is 75W-90 synthetic. I don't think there is a way for you to do a trans flush at home and make it worth your hassle. I don't think I would use anything other than what is in the trans already (hopefully what it is supposed to have in it), reason is I don't know if anything good or anything bad can happen with synthetic trans fluid either way. What I do know is it really isn't a good idea to mix different lubricants in the transmission and a flush isn't going to get everything out. The only way to make sure you have it all out is to remove, disassemble and clean every part in the trans. As far for the question of flushing I do it all the time but not for the first time on anything over 100k and anything heavy service (towing) I won't do a flush over 75k. That might be a bit over cautious but I don't want to buy anyone a rebuild. On an 01 I would probably just stick to dropping the pan and changing the filter.Oh yea and welcome to the site.