The Stovebolt Site Forums The Shop Area General Truck Talk T-5 Third Gear Grind

I really hate to even ask this question because I'm afraid what the answer might be. :mad:
After my truck has been sitting for awhile, upon start up, not at idle but acceleration and running through the gears, my T-5 grinds when shifting into third gear. After it warms up, it disappears. What might be causing this?

Joe

Joe,
The fact that it gets better when warm leads me to believe that it is filled with the wrong type of oil. If the problem was bad syncros, it wouldn't go away when everything is warm.

Got my fingers crossed for you!

Joe, like bigbad said, hopefully it has the wrong type fluid. The T5 was produced for over 20 years and had many changes. first you need to know what the tranny came out of and what year. Chevy, F**d, Jeep, AMC, and Eagle all used the same T5.
The biggest misconception is that all T5's take gear oil. There are two classes of T5's, World Class and Non World Class. Non world class were a modified T4 4speed with 5th gear added as an after thought and your gears ride on a solid shaft with no bearings so they must use 70 weight gear oil. These were found in early S10 Blazers and Astro vans made before the mid '90s. For some reason the Camaro/Firebird got the World Class trans but the S10/Astro didn't.

The World Class uses Automatic Transmission Fluid Only. Camaros and Firechickens from '88 up and got this one which switched to bearings between the gears and shaft so it must use ATF to keep everything lubed. Just about everything from mid '90s and up were World Class T5's.
If you aren't sure which one you have look for either a stamped tag on the case or numbers stamped directly on the case. You can either call your chevy dealer, look it up on the internet or just email me and you'll be sure that you're using the correct fluid. I researched all this after I found out the hard way when I used ATF in my NWC and wondered why it spit out the gears.

On the bright side, if your trans is bad (which it really doesn't sound like), you don't have to limit yourself to just a Chevy as a donor. You'd be surprised how many T5's are out there being overlooked and they are cheap and plentiful. So don't get suckered by some bonehead who thinks he is selling you gold or something.

I just scored a new bellhousing on Ebay yesterday so I can put my T5 in my '55 wagon. I hope this clears up a little for you. If you need anything else, just ask.

Good luck,
Scott

Wow Scott - Good Information!

My T-5 is a Non World Class (NWC) transmission. It came out of a 1985-1986 S-10 Blazer. The number on it is 1352-145.

There was a conversation which was pretty lengthy regarding the use of Dextron III ATF versus gear oil here on the Stovebolt page around last August. I don't remember any comments about the ATF and gear oil issue as regards the Non World Class and World Class T-5's. As I recall, the conversation centered more around the older versus the newer T-5's, and while a conclusion was never really firmly arrived at, at least to me, the consensus seemed to center around the manufacturing date of the T-5 as being the factor in whether or not to use ATF Dextron III or gear oil. I do remember some comments about the T-5, in general, having some very small passage ways in it and that was the reason for using ATF Dextron III. I chose to use Dextron III because the eveidence, as I read it, seemed to point in that direction. Now it sounds like I made the wrong choice! It sounds like the Non World Class is not the T-5 with the small passage ways and NWC is the one that would use gear oil.

If so, I need to drain the ATF out of my T-5 and load it with gear oil. Since you seem to be in tune with this issue, can you tell me what weight gear oil should be used?

Once again, www.stovebolt.com has the answer!!
Thanks Scott for this valuable information!!

Joe

It is my understanding that non-WC transmissions used a conventional brass or bronze synchro and the WC boxes use a synchro with a bonded Kevlar lining as the friction material. This requires a different lubricant to function properly.

Stuart

Wait!! Before you drain the tranny fluid out of your NWC T5 - while it's true that all WorldClass T5's use tranny fluid, not ALL NWC's use gear oil. My T5 decodes to a '89 S-10 (NWC) and the owners manual for that year says use DexronII.

So for you NWC owners out there, I would do this:
Decode the part no. of your T5 using one of the many online decoders to determine what it came out of,
Then, go to your friendly library and get a Chilton's or a Motor's Manual to match that year/model and go to the maintenance section to find out what the mfg recommends.

Joe, mine use to grind going from 5th to 4th, till I got use to it........4th is really close to reverse ........how long have you had the t-5 and when did this deal start.............hope to see you soon..

Fred

Joe,
If you go to the maintainance section in the T-5 manual that's posted on Mongos garage it says right in it that not to use gear oil. I've been using Dextron in My NWC t-5 (1352-042) for over a year with no problems.

Joe,you have the exact same transmission that i have.The factory s-10 owners manual calls for dextron atf fluid.The dealerships also say to use atf fluid.There are several shop manuals that say use atf fluid.The two t-5 transmissions that i pulled from the salvage yard had atf in them.I'm running the atf with no problems.

What type of fluid was in the transmission when you got it ? I would call around to some dealerships and transmission shops before you drain it.See if they know what is wrong with it.

Let us know what you find out.

The T-5 manual which you can download from the Tremec website covers both WC & NWC and says "Most T-5 trasmission models use Dexron II automatic transmission fluid". I pulled a 1352-145 out of an '88 S-10 and it had gear oil in it but someone had it apart as evidenced by wrench marks, different sealants, and some thrust bearing parts lodged on the magnet in the bottom. I don't think this one is the one that came in the '88. I'm rebuilding it now and planning on putting Dexron III in it. Paul over at 5-speeds.com also says all T-5's use Dexron.