HELP Please-NOISES from either Diff or Tranny-What tests?

**themexicandoctor** · 11-10-2008, 01:07 PM

Have 1999 GMC Savana 1500 Conversion Van with a 5.7, bottom line; for the poast few months I have had a whining noise that happens under load up a hill or under heavy gas pedal that sounds like it is coming from the rear diff - and then a few days ago, some guys working on my stereo locked the parkingbrake down with thier legs down and when I put my car into gear, I couldnt move it forward or back - bottom line; once we realised they had also put the speaker wires in the way of the brake release, we undid and then I slowly reversed the truck, as I did it was making an incredible grating noise from the diff or driveshaft - so I crawled down to a mechanic I know peripherally a couple of blocks away.

First thing we did was replace both U Joints, after one block test drive still noise problem and this time from the transmission (listened with stehoscope). We checked the diff and it does have oil and then the mechanic said I need a new transmission.

I crawled away a few blocks to think about it, AND, in the past few days dont seem to have the tranny problem (sometimes I hear a grating noise but only in first gear which I baby and the moment the trans moves into second that noise is gone) but still have the spinning whining noise under load.

What tests, or, checks can I do first before having a new trans, a fifth mechanic drove it the other day and said it sounds like a diff problem, not a tranny problem - I would rather invest a couple of hundred up front to know what the problem is than $2500 or so not knowing and find out I may have two problems, tranny and diff.

The tranny does shift fine - thank you, I am not a mechanic nor do I have tools but being a farmer from New Zealand have a good idea of how things works and what sounds like BS.

**CoolAirVw** · 11-12-2008, 11:12 PM

Originally Posted by themexicandoctor

sometimes I hear a grating noise but only in first gear which I baby and the moment the trans moves into second that noise is gone

Noise that changes, quiets or goes away on a shift is planet noise. meaning thats inside the trans and you'll probably need a new trans.

Your other noise could be in the trans or in the diff.

**themexicandoctor** · 11-14-2008, 12:40 AM

I had the diff opened up and everything looked good, a few gratings around the magnet, but I watched everything. New UJoints, new rear brakes and resurfaced drums, all new suspension, and the diff flush.

If I am in first and put it into nuetral and coast without driveshaft turning, the noise goes away - is this what you men by Planetary gear noise and if so, am I screwed immediately or should I keep driving it until it doesnt move anymore?

And if you had a choice between a Rebuilt Trans from the factory or a local shop, $2900 or $2100, which would you choose?

**choo** · 11-14-2008, 10:12 AM

Wish I could help,but I have a 99 Suburban that makes some messed up noises . I cant figure out if its the tranny or the diff either,it's been doing for over a year now. I've been going with the plan of driving it till it doesn't move any more.I dont trust any shops to mess around fixing everything but the right thing till i've sunk more money into the truck then I paid for it . A rebuilt 4L60E (tranny) should cost around $1000 to $1500 installed .

**themexicandoctor** · 11-14-2008, 01:38 PM

He will give you the best answer, even if you dont cant hear because your wallet and checkbook are covering both ears - but first look at the ujoints, take rear brakes apart, etc like I did - to narrow down all the other noises that happen back and down there.

I was quoted $2100 for a local rebuild and $2900 for a factory rebuild - are you a mechanic, if so, is there a difference and where do you live because I am here in Los Angeles presently and that is what was presented to me. Does that include Torque Converter repl., etc etc etc.

I am concerned that the extra weight of a Conversion Van demands a heavier duty transmission, and that maybe I could buy from a specialty shop, a stronger, better built transmission for this purpose and weight?

If you are in LA, my number is 949 274-0-646

**themexicandoctor** · 11-14-2008, 02:02 PM

for your help., Retired says research a Jasper transmission, they are worth the money if you are going to keep the vehicle for a while and there is no questions asked if there is a problem.

go to www.jasperengines.com

Does anyone else recommend them and retired, if you are still around, why Jasper, with the heavier vehicle?

**themexicandoctor** · 11-14-2008, 02:27 PM

www.jasperengines.com or 812 482-1041 ext. 2935

On Retired's advice I called them and the questions were answered perfectly and painfully, standard rebuild they do to oem specs with thier own upgrades is about $1800 for a 460?, but for $2050 you get an even better shifting transmission which is designed for heavier loads, speeds, etc.

Even better they work with your own local mechanic, the core fee is $600 if you want to hold onto yours until your new one is installed, free delivery both ways.

More importantly, they said from the standard oem specs, they make a minimum of 18 upgrades to an otherwise fragile/prone to break transmission.

Hope this helps everyone.