Borg Warner T5 Gearbox.

[John]

Hello all,
Some advice please.

I have been advised to fill my 5 speed B.W. T5 box with a 50/50 mixture of Automatic Transmission Fluid and standard gearbox oil.
I was told this was because one type was good for the synchro and the other for the bearings. Does anybody have any knowledge or experience in this area please?

Thank you. John Clarke

[Heuer]

John

John Cagliosi from Medatronics has this to say regarding lubricants: "We recommend DEXTRON III type oils. We prefer and like Mobil One ATF or Royal Purple Synchromax. Do not use conventional 80w-90w gear lube. Use of any gear lube will ruin the synchro rings and cause lubrication problems."

[John]

Hello David,
Thank you for your reply.

I was given this 50/50 mix information by a friend.

He himself had been advised to do this by Ulryk at E Type Fabs.

Just wanted to check it all out and get peoples view on this.

If anyone else has any thoughts, I would be grateful.

Thanks again for your reply David.
John Clarke.

[Heuer]

John

Ulrik's gearbox is a totally different thing to a BW (nee Tremec) T5 W/C which is, after all, a standard gearbox modified for use in the E-Type. The T5 is the largest mass produced 5 speed ever made spanning over 40 years with 265 variations and still in production today. With all respect to Ulrik I cannot see how one man in a small garage can overturn the billions of dollars spent by BW and the major oil companies on research into gearbox performance and longevity. Personally, and I own a T5, I would not even consider putting a 'home brew' oil cocktail in there and as 90% of restored E-Type's are unlikely to do more than 1,500 miles a year I fail to understand why anyone would want to mess with a proven formula. The reason ATF is specified for T5 (World Class) gear boxes is to ensure a long service life of the needle bearings under 1st, 2nd and 3rd gear - the most likely component to cause a system failure. The needle bearings have small passages that make them sensitive to lubricant viscosity. Small diameter cylindrical rolling elements that operate at high speed need a low viscosity fluid compared with the larger diameter rolling elements such as ball bearings. Gearboxes rarely fail due to the gear teeth wearing out from improper lubrication. It is usually a bearing failure. All T5 W/C must use ATF, preferably synthetic.

Perhaps after 100,000 miles there may be some conclusive proof and in 2087 owners will be saying "You know I think Ulrik may have had a point ................"

[John]

Hello again David,
Thank you once again for your interest and reply.

Ulryks advice was specifically in regard to my friends T5 box and not his own design of box. My friend tells me that Ulryk used to sell T5 boxes supplied by "The Driven Man" and advised him on the 50/50 mix around that time.

My own T5 box is filled with the 50/50 mix but has only been driven a few hundred yards and probably never got out of second gear.

Before it is back on the road properly, I think I will have to find a way of flushing the box out and refilling with the recommended A.T.F.

Does anyone know of an effective way of doing this please?

Thank you once again for your advice. It really is helpful.
John Clarke.

[Heuer]

Info on 'flushing': http://www.machinerylubrication.com/Read/864

Personally I would not bother given the fact it has not been driven. Drain the oil, preferably with the box warm, and leave overnight to drip clear. Then refill with synthetic ATF which will dilute any remaining gear oil. I suppose if you are really concerned you could drain and refill after a couple of thousand miles but I doubt it is necessary.

[John]

Hello David,
Again, Thank you.

I will do as you suggest and drain the mix overnight and then refill with the recommended A.T.F.

As a further precaution, I think I will empty again after a few miles and refill again just to be on the safe side.

You're right of course, that given the millions of pounds spent on lubricant research on these boxes, it is not sensible to mess with things. Not good advice given to start with I think.

I notice you say you have a T5 box yourself. Mine is a Derek Watson version. Do you have any experience of these? Any advice you may have regarding this version?

Thank you again David. This really is very helpful.
John Clarke.

[Heuer]

John

Mine is a Derek Watson T5 but the experiences have not been good. It first failed within 5,000 miles because the circlip retaining the speedo worm broke. The circlip holds the speedo worm in place which holds 5th gear in place - ergo, the circlip fails, speedo stops working (the alarm bells should ring!) and fifth gear cog can move backwards which will destroy the box. Watson took the engine/box out (twice as it happens) and put in a stronger circlip and a deeper groove in the main shaft for it. This failed again at 15,000 miles so the car was transported to CMC who sent the box to Elite Racing. They had it apart and suggested and even stronger circlip but I elected to have the thing Tig welded in place Means the box cannot be economically repaired in the future but at least nothing is going to move!

This is a design failure with the DW and other Medatronics JT5 'clone' boxes because of the way they have arranged things which means the speedo drive is always putting pressure on the worm to act against the circlip. The Medatronics JT5 designer spotted this problem and reversed the worm/speedo gear so it is acting away from the circlip hence it is never under pressure. Chapter and verse here: http://www.5speeds.com/copycats.html

Don't worry too much about your box though if you have an otherwise standard car. My OTS has 350lb/ft, a 2.88 diff and I drive it very hard. I think my troubles began when I fitted a Halda meter to do the Rally des Alpes which ran off the speedo cable. No excuse really as it should still have been able to cope. Unfortunately we are very limited in the choice of 5 speed conversions - DW T5 no longer produced, ETypeFabs is still in production, Medatronics will not supply the JT5 to the UK, the Getrag is ill suited to the E-Type and the Broadsport box requires expert modification/fitting. The Driven Man T5 box is currently another option I suppose.

All I can suggest is if your speedo stops working, stop and get the car recovered or take a chance and drive home slowly. Engine/box out job though

[John]

Thank you David.

Food for serious thought certainly.

I didn't know that Derek Watson box is no longer supplying these boxes. Is this because of problems similar to yours do you know?

When yours failed, did the box lock up on you? I have to say, I'm more than a little concerned at the prospect of that happening at speed.

Thanks again. John.

[Heuer]

I heard DW had stopped supplying the boxes due to warranty claims but that was hearsay. The box does not lock, at least initially and not at all in my case. I managed to drive from Kent to Nottingham with the speedo stopped (I did not know the prognosis then) and then a very spirited drive from Nottingham to Derek Watson at which point he confiscated it and drove me home in his car! So yes it is very serious IF that 5th gear moves backwards. My box was bought about 10 years ago so hopefully there will have been a triumph of development over design and your box will not be at risk. There are a fair number of similar T5's out there made by Glebe and Elite so they must have sorted the problem by now. Worry not, drive the car, enjoy it but in the unlikely event the speedo suddenly stops, suggest you do the same. I am the only one I know who has had the problem but Glebe, Elite and DW know about it so they must have some experience. If you bought the box from Derek give him a call and seek reassurance.

[MarekH]

Dear David,

I am curious as to why you say the Getrag is not well suited to the etype.

It was fitted to heavier v12 Jaguars which have as much if not more hp and torque and I'm not aware that there were any warranty issues or complaints from the original owners, so what have I missed?

kind regards
Marek

[John]

Many thanks David.
I shall take serious note of all you have said. I shall start by draining the box and refilling etc.etc.

I WILL OF COURSE, keep an eye on that speedometer also !!!

Thanks again, this has been most helpful to me I assure you.

John.

[Heuer]

Dear David,

I am curious as to why you say the Getrag is not well suited to the etype.

It was fitted to heavier v12 Jaguars which have as much if not more hp and torque and I'm not aware that there were any warranty issues or complaints from the original owners, so what have I missed?

kind regards
Marek

Marek

The Getrag box is no suited to the sporting 'character' of the E-Type. Ideal in a big lazy V12 but not good in a straight six. Nothing to do with reliability which I am sure is sound.

[MarekH]

Another consideration:- it is quite a long gearbox and so fits better in a long wheelbase car than a short wheelbase car.

kind regards
Marek

[PeterCrespin]

The Jaguar Getrags, both 265 and 290 are long, but there are BMW Getrags which are not. Those are the ones used in SWB E-types like mine.

Pete

[steve3.8]

I had a 265 short box kit [photo] sat in the garage for a good while but did'nt fit it and eventually sold it ,its worth noting anyone trying to go down this route that the dogleg gate pattern box are 1-1 final drive thus defeating the object of a 5th gear,mine was H pattern gate with 5th being 0.81 O/D but both gearboxes look the same .For the swb cars there are far better options nowdays.

The advice passed to John about mixing atf/gearoil maybe is a to keep the viscosity up--as i would guess the billet gearbox with a thicker wall section would increase the internal working temperature? although it seems too risky to invent a mixture ,and the internals of which i always thought were T5 gearsets,does anybody know which?

[5speeds]

i would guess the billet gearbox with a thicker wall section would increase the internal working temperature? although it seems too risky to invent a mixture ,and the internals of which i always thought were T5 gearsets,does anybody know which?

Hi haven't posted here in awhile, but sometimes the misinformation gets propagated to a point of stupidity.

The MAIN REASON for ATF only in the T5 is CLEARANCE and oil flow. The E-Type Fabs and CJ5 are in fact T5 based units. Most internals are stock T5 gears other than inputs and outputs. If you want to believe the "hype" go ahead. The carbon fiber synchro rings also require a thin viscosity fluid such as ATF to keep them cool. No need to mix this stuff. You risk heat check and damage to the needles and also create more horsepower losses.
Just use a good synthetic such as Mobile one or Royal Purple. REMEMBER not one of these people selling their 5 speed kits builds the volume of race endurance transmissions as we do. We build for example units for La Carrera Panamericana, T5 units running 2500 plus miles all out for 3 days. No coolers no heat issues. Try that will a non finned Billet box and you will have a melt down.

[steve3.8]

I take it you?re refering to my post to answer the gearset question only. No misinformation or stupidity, otherwise you would rather seem to be contradicting yourself in your last sentence!

[1954Etype]

i would guess the billet gearbox with a thicker wall section would increase the internal working temperature? although it seems too risky to invent a mixture ,and the internals of which i always thought were T5 gearsets,does anybody know which?

Hi haven't posted here in awhile, but sometimes the misinformation gets propagated to a point of stupidity.

The MAIN REASON for ATF only in the T5 is CLEARANCE and oil flow. The E-Type Fabs and CJ5 are in fact T5 based units. Most internals are stock T5 gears other than inputs and outputs. If you want to believe the "hype" go ahead. The carbon fiber synchro rings also require a thin viscosity fluid such as ATF to keep them cool. No need to mix this stuff. You risk heat check and damage to the needles and also create more horsepower losses.
Just use a good synthetic such as Mobile one or Royal Purple. REMEMBER not one of these people selling their 5 speed kits builds the volume of race endurance transmissions as we do. We build for example units for La Carrera Panamericana, T5 units running 2500 plus miles all out for 3 days. No coolers no heat issues. Try that will a non finned Billet box and you will have a melt down.

Paul, all well and good but you don't sell your boxes in the UK now! ;)

[5speeds]

Paul, all well and good but you don't sell your boxes in the UK now! ;)

Its not about selling my gearboxes here. The stupidity is not directed at you. Just the general nonsense perpetuated on forums that is totally invalid. Furthermore, if you want to negate my expert advice because I don't sell TO DEALERS in the UK.... well thats pretty sad to me...

Billet cases are much weaker than the die cast finned ones. The false advertizing of some people making claims of Horsepower ratings over 350 HP is a shame. If you think about it. The 5speed market for a Jaguar deals with the majority of cars under 400HP, so you can overrate the transmissions knowing, nobody will reach that mark. Having already witnessed a rash of cracked billet cases and melted gear sets with pretty much stock units I seriously doubt the volume claims people are making. I've got a pretty solid record of race transmissions in alot of cars. Some in the fastest Jags in the US.