Gearbox and diff oil choice
Gearbox and diff oil choice
Author
Discussion

Russell Mc

Original Poster:

573 posts

175 months

Tuesday 17th January 2012
quotequote all
Im changing these for the first time in my ownership. The oils Im going for are Castrol Syntrans Multivehicle 75W-90 Fully Synthetic MTF for the gearbox and Castrol Syntrax Limited Slip 75W-140 for the diff. The car is a precat. Do these sound like good choices?

carsy

3,019 posts

189 months

Tuesday 17th January 2012
quotequote all
Looks spot on to me.

Russell Mc

Original Poster:

573 posts

175 months

Thursday 19th January 2012
quotequote all
Excellent.
Ordered it yesterday. Free delivery from Opie Oils at the moment too

gizzer

671 posts

230 months

Thursday 19th January 2012
quotequote all
carsy said:
Looks spot on to me.
NOT sure but unless u have a t 5 box fully syn is not rite

PeteGriff

1,262 posts

181 months

Thursday 19th January 2012
quotequote all
gizzer said:
NOT sure but unless u have a t 5 box fully syn is not rite
Gizzer is right, I have a 4.3 Pre-Cat and it has the LT77 box. This box must have ATF fluid not gear oil. Oilman at Opie Oils can advise on this, I get all my oils from him, he supplied a very good quality high performance ATF oil for my box. I used a FUCHS oil in my diff (GKN) again supplied by Opie. Regards,Pete

Russell Mc

Original Poster:

573 posts

175 months

Thursday 19th January 2012
quotequote all
I was under the impression that ATF was only recommended from the factory to give a smooth shift from cold but did little to protect the box in the long run?

carsy

3,019 posts

189 months

Thursday 19th January 2012
quotequote all
Russell Mc said:
I was under the impression that ATF was only recommended from the factory to give a smooth shift from cold but did little to protect the box in the long run?
I think you are correct but others may not.

This is my take and experience with the LT77 gearbox.

I got mine re built and so wanted to put the correct and best oil back in. I did a

lot of research which ended up inconclusive. There seemed to be a split

between people recommending atf and others recommending mtf such as castrol smx,

and other using synthetic engine oil.

The mtf, castrol smx sat well with me and i agreed with the theory that it should

protect the box better than atf. there were also a lot of people on here using it.

So in went some castrol smx. Felt good but the gear change became stiff when

everything got hot. I thought this was perhaps because the oil was slightly too

thick but turns out it was the clutch master cylinder calling it a day. Before

realising it was the master cylinder at fault i decided to try all other oil

options. This included atf and Honestjohntoo`s recomendation of Synthetic Mobil 1

0/40 engine oil.

The atf felt dreadful. felt like there was just water in the box and i could feel

metal on metal every change. Really felt like there was little or no protection in

there. This lasted about a week and then out it came for the Mobil 1 engine oil. I

have to say this feels really good. Nice n smooth hot or cold and just feels good,

nothing like the atf. In comparison it probably feels the same as the castrol

smx. I have since changed the master cylinder but due to the Mobil 1 feeling so

good i have left it in. When i do change it i will probably go back to smx or

whatever its now called but have to say the Mobil 1 feels very good.

So in my experience and opinion stick with the castrol mtf or synthetic mobil 1

0/40, engine oil. There will be those that disagree but hey ho.



PeteGriff

1,262 posts

181 months

Thursday 19th January 2012
quotequote all
Russell Mc said:
I was under the impression that ATF was only recommended from the factory to give a smooth shift from cold but did little to protect the box in the long run?
Not the case, speak to Opie Oils! My griff has done 73K now and has always had the ATF oil, I have just changed it again. It is a Land Rover box and they run on it, my Land Rover has now done 110K and the box is still going strong. Pete

carsy

3,019 posts

189 months

Thursday 19th January 2012
quotequote all
yes but they werent designed to run on it. it was a bodge fix to make it useable when cold.

Do a search on the Wedge forum and see what those boys are using and their experiences. Modern synthetic oils are a world apart from what was around when the LT77 was born.

I`m not saying atf is wrong and it is not as you can verify but i think synthetic mtf is better.

Russell Mc

Original Poster:

573 posts

175 months

Thursday 19th January 2012
quotequote all
Opie Oils know oils but are they experts on gearboxes? Surely they just recommend ATF because thats what Land Rover and TVR say should be in there?

carsy

3,019 posts

189 months

Thursday 19th January 2012
quotequote all
Exactly.

carsy

3,019 posts

189 months

Russell Mc

Original Poster:

573 posts

175 months

Thursday 19th January 2012
quotequote all
Interesting little read. Think I'm going to try the new oil and see how it goes. Maybe the first to second shift will have to be taken a little slow when the engine/box is cold but surely its worth it if it provides better protection once warmed up

PeteGriff

1,262 posts

181 months

Friday 20th January 2012
quotequote all
Points taken guys, but I can only go on my experience - Land Rover with LT77, 110K miles, used for heavy regular towing, never failed or complained apart from the need for a new O/P shaft seal - Griff 430 with LT77, 73K miles, always had ATF (from records), still running well and changes smoothly. Pete

Griffith77

41 posts

172 months

Friday 20th January 2012
quotequote all
Just had the LT77 & GKN rebuilt and picked up today - had exactly this conversation with Bernie @ CTS.

His recommendation was (Morris) ATF D2 for the 77 and XFS 80W/140 API for the diff.

Having spent a few pounds on this i'm keen not to have to do it again anytime soon so will probably go with Bernie's recommendations - after all he's looked after loads of the Tuscan race boxes as well as road going TVR's so should know what works.

Interesting to see peoples experiences though....


PeteGriff

1,262 posts

181 months

Saturday 21st January 2012
quotequote all
Griffith77 said:
Just had the LT77 & GKN rebuilt and picked up today - had exactly this conversation with Bernie @ CTS.

His recommendation was (Morris) ATF D2 for the 77 and XFS 80W/140 API for the diff.

Having spent a few pounds on this i'm keen not to have to do it again anytime soon so will probably go with Bernie's recommendations - after all he's looked after loads of the Tuscan race boxes as well as road going TVR's so should know what works.

Interesting to see peoples experiences though....
Hi Griffith77, had my GKN diff recently rebuilt by Bernie, nice job, the Griff seems to run much better now with no noise at all from the rear! I went with Fuchs Titan Race Diff Oil, and of course a good quality ATF in the box. Pete