transmisson fluid?

[mtlman8]

First and foremost... THANK YOU ALL!you have all helped me to get the motor started after 26 years...adjust the carbs... rebuild the clutch and brake master cylinders...now I'm just about ready to put her on four wheels and drive her around the block... but first I want to drain and refill the tranny, should I fill it with ATF. and run it through all the gears (as for the detergent) or just fill it with gear oil? BTW? what wt. oil should I use?

 

[tdskip]

I'd sy away from ATF and go with factory spec oil. What car do you have? Does it have an overdrive?

 

[mtlman8]

67 tr4a no overdrive (I think)

 

[tdskip]

There is some debate on this topic;

https://www.quantumechanics.com/categories.php?op=newindex&catid=11

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]
Gang – I apologize for not writing an article for some time, but between the rough winter and everything else going on, it was impossible!

I want to express our experience and opinion on the topic of the proper oil for use in the Laycock de Normanville overdrive units. We constantly get into discussions( and sometimes heated debates!) with British car owners on this subject. This month’s discussion will invariably get some interesting responses as it seems to be a rather emotional (and not necessarily logical) discussion item for British car overdrive owners.

Let’s start out with history. Historically even the recommendations from various car manufacturers are confusing. Some say to use multi grade oil (MG manuals), some hypoid oil (Triumph manuals), some non detergent oil and some even recommend automatic transmission fluid! No wonder everyone is so confused!

Many years ago (in a land far, far away (OK it wasn’t that far away or even that long ago)) we ran an experiment on overdrive oil. We rebuilt an A type overdrive unit and initially ran it with 30 weight non detergent motor oil. When spun up on our test bench at 1,000 RPM, it reached a normal pressure of 400 PPSI. When shifting the pressure dropped to 300 PPSI and quickly recovered to 400 PPSI. All was right in the world of overdrives.

We then drained the oil and replaced it with 10W30 multi grade oil. When spun on the test bench, initially it tested fine. However, after a few minutes of running, the oil pressure dropped to 300 and when shifting, to 200. Upon observation of the internals of the operating overdrive we found bubbles developing in the oil pump body and oil pump output passage. We surmised that the detergents in the oil were causing the oil pump to cavitate, and develop air bubbles as it pumped.

We then drained the oil again and replaced it with 90 weight hypoid oil. This time the oil pressure jumped to 600 PPSI! When shifted, the pressure dropped to 450 PPSI, which made the shift immediate and harsh. After a few minutes of running the oil pressure actually began to climb even higher. (Which made no sense since we thought the oil would thin out and the pressure would drop). We finally shut it off at 750 PPSI as we did not want to damage the unit. Even though the overdrive unit was now in the non overdrive position (solenoid disengaged), the overdrive was now stuck in overdrive and would not come out. The higher pressure had driven the sliding clutch member so hard into the brake ring that the clutch return springs could not return it to the non overdrive position. A tap on the brake ring with a hammer (the universal overdrive release tool), shifted it back into the direct drive position. After running a number of these test with the same result we found what was happening. The oil holes in the accumulator sleeve are very small. The 90 weight oil was so heavy it could not escape from the accumulator chamber as fast as the oil pump could pump new oil into it. So even though the accumulator piston had passed the oil hole relief position, the pressure continued to build up because the oil could not leave the system as fast as it was being pumped in. The accumulator piston actually bottomed out in the sleeve (similar to coil bind on valve springs). When removed we found the accumulator spring had been compressed and was no longer useable.

After replacing the spring, we then tried automatic transmission fluid. We saw the same results as we did when we used the 30 weight non detergent oil.

We then tried synthetic oil and the unit also worked OK although it began to leak from all sorts of places it had not leaked from before.

Based on these tests we have since and continue to recommend the 30 weight non detergent motor oil as the best oil to use in the overdrives.

Some other experiences with customer overdrives over the years have reinforced this choice. For example, we found a Jaguar compact overdrive with a broken accumulator piston and bent spring when it had been used with 90 weight oil by the owner. When the piston and spring were replaced and the unit filled with 30 weight non detergent oil, it functioned normally. A customer LH overdrive unit that was filled with 90 weight oil "pulsed" between direct drive and overdrive without even being switched on electrically. When the oil was flushed and replaced with 30 weight non detergent oil the unit worked normally.

Other noted problems with overdrives filled with 90 weight are excessive wear on the oil pump plunger wheel and the eccentric cam, probably due to the higher pressures developed. Also the clutch lining seems to be more deteriorated in units with 90 weight oil than those with 30 weight oil.

The use of non detergent 30 weight oil does not seem to affect the transmission parts or function. Bearings, synchros, gears and hubs do not seem to function any less effectively with the non detergent 30 weight oil as with 90 weight gear oil.

So there it is gang, our scientifically based rationale for using and recommending 30 weight non detergent oil in Laycock overdrives. I welcome further discussion and feedback on this topic by anyone interested. As always, thanks for reading this article! [/QUOTE]

 

[TR3driver]

Yeah, and that article only scratches the surface of the debate. While John is certainly a respected OD rebuilder; it's hard to believe that the Triumph-recommended gear oil causes instant malfunction on the bench. Lots of folks, myself included, have tried to duplicate that result and failed.

But still, that article is about OD lubes, while this question is about a non-OD gearbox. Hard to go too far wrong, IMO, following the factory recommendation (which was for GL-4 gear oil).

That said, I've switched to using Redline MT-90 (which is a full synthetic GL-4 gear oil). It's expensive, but worth it IMO. And it has none of the "active sulfur" additive found in some conventional gear oils, that can shorten the life of "yellow metal" components like thrust washers and synchro rings.

 

[shining_armor]

Spec for that car should be 75W-90 gear lube, GL-4. A number of synthetic GL-5 gear lubes are also safe for GL-4 (brass components). Redline and Amsoil (GL-5) are both rated safe for GL-4 spec. The debate regarding overdrive lube is not relevant to your trans.

Ernie

 

[tdskip]

But still, that article is about OD lubes, while this question is about a non-OD gearbox. Hard to go too far wrong, IMO, following the factory recommendation (which was for GL-4 gear oil).

Oh, duh. Misread that. Sorry guys.

 

[TR3driver]

A number of synthetic GL-5 gear lubes are also safe for GL-4 (brass components).

Safe, yes, but they can interfere with proper synchromesh operation (which relies on a certain level of friction between the syncho rings and gears).
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Redline and Amsoil (GL-5) [/QUOTE]Most of Redline's GL-5 oils are specifically NOT recommended for transmission use. For example, their 75W90 GL-5 Gear Oil states:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]This product is not designed for use in most manual transmissions or tranaxles, since the extreme slipperiness may cause synchronizer mesh issues that lead to shifting problems[/QUOTE]
https://www.redlineoil.com/product.aspx?pid=133&pcid=4

But Redline MT-90 and MTL (which are specifically designed for use in manual transmissions) are only rated GL-4, and in my experience provide excellent synchro operation.

 

[Mickey Richaud]

Randall -

Do you know if Pennzoil Synchromesh Fluid has been tested in OD trannies? It's the oil of choice for Wedge 5-speeds, and I have it in mine. Don't want to muddy up the water; just wondering...

Mickey

 

[tomshobby]

That said, I've switched to using Redline MT-90 (which is a full synthetic GL-4 gear oil). It's expensive, but worth it IMO. And it has none of the "active sulfur" additive found in some conventional gear oils, that can shorten the life of "yellow metal" components like thrust washers and synchro rings.

I totally agree with Randall. I changed to Redline MT-90 a couple years ago. My non-OD transmission is now so quiet that I cannot even hear it and the shifting is smooth as silk. I look at the cost as very cheap compared to the result.

 

[TR3driver]

Do you know if Pennzoil Synchromesh Fluid has been tested in OD trannies?

Nope, don't know anything about it one way or the other.

 

[TR3driver]

Just for chuckles, here is the relevant page from the TR4A Owner's Handbook
https://i258.photobucket.com/albums/hh260...ntsOverseas.jpg

 

[tdskip]

Do you know if Pennzoil Synchromesh Fluid has been tested in OD trannies?

Nope, don't know anything about it one way or the other.

Oil of choice for TR7/8 gearboxes..., but that is another conversation.


(sorry again about the OD post - I was really not in the swing of things.)

 

[shining_armor]

A number of synthetic GL-5 gear lubes are also safe for GL-4 (brass components).

Safe, yes, but they can interfere with proper synchromesh operation (which relies on a certain level of friction between the syncho rings and gears).
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Redline and Amsoil (GL-5)

Most of Redline's GL-5 oils are specifically NOT recommended for transmission use. For example, their 75W90 GL-5 Gear Oil states:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]This product is not designed for use in most manual transmissions or tranaxles, since the extreme slipperiness may cause synchronizer mesh issues that lead to shifting problems[/QUOTE]
https://www.redlineoil.com/product.aspx?pid=133&pcid=4

But Redline MT-90 and MTL (which are specifically designed for use in manual transmissions) are only rated GL-4, and in my experience provide excellent synchro operation. [/QUOTE]

Royal Purple's Max Gear 75W-90 is rated for both GL-5 and GL-4 and fine for manual transmissions. Amsoil's Severe Gear 75W-90 is rated GL-5 and fine for GL-4 and fine for manual transmissions.

Ernie

 

[Geo Hahn]

67 tr4a no overdrive (I think)

If you happen to find the rear section of your gearbox looks like this:

Notify me at once and I will drive up to PHX and help you remove it.

 

[RJS]

Mine is a 66 TR4A with OD trans. About 2 years ago, on the recommendation of the article above, I switched from 75W-90 GL4 gear lube (after 8 years) to non detergent SAE 30 motor oil. I never had any issue with the 75W-90. And, I would say the SAE 30 performs identically with the one exception that on very hot days after a long drive, I have detected some "notchiness" shifting into 3rd gear. I suspect this is when the oil gets hot and thins a bit, it isn't spinning the synchros sufficiently. So, this fall I am considering either
a) switching back to 75W-90 GL4 (which is what I use in the diff already), or
b) going to a Redline synthetic (which one for an OD trans?)

Randall, you say you use MT-90. Do you have an OD trans?

Bob

 

[TR3driver]

Randall, you say you use MT-90. Do you have an OD trans?

Yes. I use MT-90 in both the A-type on my TR3, and the J-types on my Stags. I even emailed Redline, and MT-90 is what they recommend for all Laycock-type ODs.