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MG MGB GT V8 Factory Originals Technical - T5 question

Where is the filler hole on a GM T5? Ive heard that there is at least one bolt that you can't remove or you'll have big internal problems.
Jake

One option is to pour it in the shifter opening. Something like 2.6 or 2.7qt of Dextron II for a GM version is the full capacity with rotated the 17 degrees.
Scott

There should be two plugs on the passenger side; one to fill, one to drain.

The non-world class T-5s use gear lube.

The world class T-5s use ATF.
Glenn

Thanks guys, Ill try it out tomorrow, as I picked up the driveline today, so it won't all run out the back.
Jake

Glenn,

I checked with the dealer on the correct lubricant for my NWC T5 and was told to use either Syncomesh(sp) or ATF.

Scott
Scott Costanzo

Scott, your dealer may be mistaken, check this out:

http://www.asedan.com/t5b.htm

Wouldn't hurt to consult an owner's manual or Hayne's book to be sure.

Good luck.
Glenn

Glenn wrote:

"your dealer may be mistaken"

Dealers are notorious for not knowing what they are talking about. As a general rule, I would never ask a dealer about anything!

And that's not even taking into account the fact that they will flat out lie if it serves their purpose!

From what I've read (but I'm certainly no expert), Glenn is right about which lube to use.
Dan Masters

Every manual I have refers to ATF for Ford and GM T5's.
Dann

The Tremac T5 service manual says to use Dextron II in T5s both WC and NWC-- it also cautions DO NOT use gear oil in a T5 as it may cause damage to the blocking ring material.So ATF is the recommended fluid. I am using Red Line in mine that I rebuilt last winter and it has run beautifully all season. fww
Gil Price

Gil, I'm looking at a Tremec T5 service manual (Bulletin No.LD05-0510-0199)right now, and it states:

"2-4. APPROVED LUBRICANT. Most T5 transmission models use Dextron II automatic transmission fluid. Refer to the vehicle owner's manual or service manual for lubricant specifications.

CAUTION

Do not mix different brands or types of lubricant. DO NOT USE GEAR OIL IN THE T5 TRANSMISSION SINCE THIS MAY DAMAGE THE BLOCKING RING MATERIAL."

There's definately a gray area here. They say "Most T5 transmissions", which by my understanding doesn't mean all. They also say to refer to a manual.

Perhaps the most serious mistake is to put gear lube in a T5 which is supposed to have ATF, and perhaps a T5 which orignally used gear lube will operate fine with ATF. I really don't know.

My son's 82-93 Hayne's S-truck repair manual lists Dextron II or IIE ATF for the recommended manual transmission lubricant.

I'm stumped - everything I recall reading until now specified gear lube for NWC and ATF for WC T5s.

Once again, maybe the thing to avoid is running gear lube in a WC T5, while running ATF in a NWC (although possibly not used originally) won't hurt it.

How did your T5 rebuild go? Anything in particular to look out for?
Glenn

Gear oil or ATF?

I thought I once read somewhere that the very early GM T-5s did use gear oil.
Carl

This link agrees with Glenn, although it is mostly Ford related:

http://www.moderndriveline.com/Technical_Bits/t5_history.htm


<<Which type of oil is used in a Non World Class T-5?

70w gear oil, as there are no bearings under each gear and the syncro's are bronze. >>

http://www.5speeds.com/t5/index.html

<<There are 2 basic kinds of T5 5 speeds. Non World Class ( NWC ) and World Class ( WC ). The T5 is an evolution of the Borg Warner SR4 4speed. The SR4 was a lightweight design, ball bearing and needle bearing counter gear box using bronze synchro rings. The T4 was an improvment of this design, using tapered input and output shaft bearings combined with a drawn cup roller bearing countergear. The T5 NWC was a T4 with an added 5th gear.>>



Carl

Carl, this I know for sure if it will help. The Chevette did use gear oil in first and later production and most likely all standard shift GM models that used the T5 at that time. The Muncie plant was phasing out transmission production about that time. It was only a suggestion from a line mechanic at a dealership, I believe in Warren, Michigan, that ATF be used because the locals that owned Chevettes complained they had to warm their cars up for a substantial period because of the sub zero temperatures they encountered in the winter months. I was an engineering student at the time and I saw the bulletin when I worked part time as a new vehicle get ready mechanic working for a local Chevrolet dealer. It was apparently passed on to the dealerships as a suggestion and we sort of adopted it as standard procedure as a fluid check and change. I suppose that sometime later engineers made the change standard at the production level. Hope this helps, Dann BCC
Dann Wade

My T5 is a WC so no question of using anything but ATF.To quote words of a rebuilder "the lubrication passages are so small that gear oil will not flow readily and lubricate properly. You stand a chance of spalling, galling or otherwise destroying a trans if pushed to extremes."
As far aa I'm concerned the guys working on these everyday dont recommend gear oil.
My car has a 302 Ford so only a WC was what I wanted.
The rebuild is fairly easy if you take time and effort to do it properly. I bought my rebuild kit from Hanlon Motorsports in PA. His prices are good --quality parts and he has a step by step rebuild video that is of great help.
I can believe early Chevettes used gear oil --in this north country you couldnt shift them !

Gil Price

My ShopKey program states the following for manual transmissions used on Vette's, Camaro's and Mustangs.

---General Motors--
Manual Transmission (Except 69.5mm, 70 mm and Camaro/Firebird 76 mm) use SAE 80W or SAE 90W of API Gl-5 qaulity.

Manual Transaxle (Including 69.5mm and 70 mm transmission) use SAE 5W-30 engine oil SF,SF/CC or SF/CD.


Manual Transmission (Corvette Overdrive Unit and Camaro/Firebird 76mm) use SAE 5w30 engine oil SF,SF/CC or SF/CD.


Borg-Warner 77mm 5 speed use Dexron II ATF.

---Ford---

Ford T50D Manual 5 speed use Type F, Dexron II, or Mercon ATF.

Hope this clears up some confusion.
Joaquin

This thread was discussed between 25/10/2003 and 26/10/2003

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