his new gearbox? (Rover LT77 to TR)

[JochemsTR]

my gearbox friend ordered some new parts. Final assembly. not only does it look good, it shifts good too.

[Z320]

Hi Jochem,

this make me very pleased because I worked with the empty gearbox and had no possibility to check.

Further much success!

Marco

 

[Z320]

Jochem,

I know your LT77 gearbox works now in your TR6.

What about an update here at the forum, if you like?

I‘m looking forward for your next project!

Ciao, Marco 

[JochemsTR]

2 hours ago, Z320 said:

Jochem,

I know your LT77 gearbox works now in your TR6.

What about an update here at the forum, if you like?

I‘m looking forward for your next project!

Ciao, Marco 

Sure, here it is.

After initial installation and first test drive, I was amazed with the ease of shifting. The gearbox is short and direct. For me personally, I find it a lot more pleasant to drive in 5th gear vs using the overdrive. The LT77 does not extend towards aft as much as an J-OD does and this became very convenient. I was worried about some rattling in the gearbox. First thought was the clutch bearing, since pressing the clutch made the noise dissappear but the noise came from the main gearbox. I removed the gearbox brackets and I could remove the gearbox down. The whole operation was done in about 45 minutes.

The gearbox was carefully inspected again, actually taken apart, and no damage or wear could be found. Some parallel investigation turned a few causes for this matter.

1. rotational non-uniformity. I had the gearbox out, used an electrical drill.....surprise...no noise! smooth running. However, lightened flywheel, race cam, introduce an unequal torque which transfers into the gear box. With its backlash, this noise becomes apparent.

2. Oil. Rover and even Ashcroft advise on ATF Dexron II/III. However, the LT77 was never designed for this oil. It just improved shifting in cold. On a later date, MTF94 was approved. Wow!! Surprise. Looking at the viscosities, they are almost identical !! In various forums, LT77 Gearbox oil is discussed. A most interesting subject. Some tests were done with Castrol SMX-S. Best results achieved. Occasional scratching going from 1st into 2nd, but warm, the smoothest shifting ever. However, SMX-S no longer exist. Its successor Syntrans, no longer exists either. But there is a new player. Castrol Transmax series. 75W-80 or 75W-90. The famous 75W-85 is no longer offered. As I mentioned, the LT77 was not designed for ATF Oil, but Motul 75. This viscosity is very close to a 75W-90 oil !! Long story short, I ended up using 75W-80 and 75W-90 mixture and I can only say, I am more than pleased with cold and warm shifting and the annoying rattling has almost reduced to zero.

 

I am gathering parts for another LT77 gearbox to keep as a spare or maybe sellling. Conrad helped me with my bell housing (very rare) and I found a dissassembled LT77 Suffix D (I have C) for about 150 Euros. Main, Layshaft in very good condition, so this one will get new bearings, small parts and assembled again. Done.

Jochem

 

 

 

[Z320]

Great!

[BlueTR3A-5EKT]

Is not the bell housing fitted to Range RoverV8  or Rover SD1 3500 saloon with that gearbox and the short remote extension is Sherpa Van?

 

PS probably fitted to A

”Adder” or MGRV8.    Not a lot of those in the breakers!

Edited July 2, 2022 by BlueTR3A-5EKT

[JochemsTR]

The bellhousing I am referring to, comes from Rover SD1 2.3 and 2.6 engines.

Jochem

Edited July 3, 2022 by JochemsTR

[Z320]

Time to say goodbye today to parts for another LT77-TR gearbox.

Very pleased I'm about the new design of the excenter, made on my new 4 jaw chuck.

The first one, still in use, had a poor design and suffered from my lack of tools and material.

I hope it will find the way to the bin...

Ciao, Marco

[JochemsTR]

again, a nice piece of work.

My second LT77 Gearbox will enjoy it.

[greasemonkey]

On 7/2/2022 at 12:49 PM, JochemsTR said:

Sure, here it is.

 

2. Oil. Rover and even Ashcroft advise on ATF Dexron II/III. However, the LT77 was never designed for this oil. It just improved shifting in cold. On a later date, MTF94 was approved. Wow!! Surprise. Looking at the viscosities, they are almost identical !! In various forums, LT77 Gearbox oil is discussed. A most interesting subject. Some tests were done with Castrol SMX-S. Best results achieved. Occasional scratching going from 1st into 2nd, but warm, the smoothest shifting ever. However, SMX-S no longer exist. Its successor Syntrans, no longer exists either. But there is a new player. Castrol Transmax series. 75W-80 or 75W-90. The famous 75W-85 is no longer offered. As I mentioned, the LT77 was not designed for ATF Oil, but Motul 75. This viscosity is very close to a 75W-90 oil !! Long story short, I ended up using 75W-80 and 75W-90 mixture and I can only say, I am more than pleased with cold and warm shifting and the annoying rattling has almost reduced to zero.

The LT77 is used with many variations of the Rover V8 engine. TVR, Range Rovers etc.. plus Cobra replica kit cars. All the V8 specialist engine/gearbox builders recommend ATF is used in the LT77 because the oil pump in the 'box has plastic vanes which, over time, will not withstand the use of a heavy conventional gear oil. It just has too much resistance to being pumped when cold. This is why Rover changed their original recommendation to ATF after a series of failures under warranty.

Phil.