LT77 and LT85 dimensions differences

[Lotz-A-Landies]

Hi people

I know that the R380 is about 30mm longer than a LT77 but I'm not aware about the differences with the LT85.

Does anyone know what are the differences between the positions of the mounts prop shafts etc between the LT77 in a Defender and an LT85 in a county. Am particularly interested in the prop shafts and gearbox/chassis mounts and whether you could swap one box to the other chassis?

Diana

[Bush65]

AFAIK the bolt positions on the chassis didn't change between either of those boxes. The RH mount bolts to the LT230 transfer case and as the chassis holes on the LH side are fixed then the appropriate bracket that bolts to the particular gearbox should compensate for differences in the gearbox.

[Terrain Vehicles]

When converting to Tdi, I took an LT85 out of my 130 and fitted a LT77. The mounts were fine, but the prop-shafts wouldn't fit and I need new ones. The front was too short and the rear was too long IIRC. I used the front prop off the donor vehicle, but had to buy a new rear on as the donor was a 110.

[Freestyler]

I have got a LT 77 out of a disco fairly sure there weren't any differences. Also have a couple of LT85's, I would have to measure them though. As far as I know any differences were taken out in the bell housing and the LT230 that is on both are in the same spot etc. If you are thinking of pulling out an LT85 and putting in an LT77 that is a big backwards step in strength! I have had both apart, the 77 is a nicer box especially to drive but they are a car gbox compared to an 85.
Tim

[Lotz-A-Landies]

Thanks Tim

The issue is that I have a V8 D150 with the LT77 and I'm going to fit a 4BD1 with an LT85 and want to sort out what I'm up for.

Currently I have: V8 Defender LT77 and LT230
V8 Disco 1 R380 and LT230
LT85 Isuzu bellhousing
County LT230 without linkages.
Option to buy = V8 County LT85
Option to swap = 1.003:1 LT230 for any of the above.
What I don't know is: if I can fit the either of the V8 LT230s to the county LT85 (linkages),
whether the prop shafts will be correct lengths, or
what transfer ratios I need for the 4BD1 (I'm thinking the 1.222:1 Disco ratios).
Diana :confused:

[isuzurover]

AFAIK all LT230s will bolt to any R380/LT77(S)/LT85/ZF (with spud shaft).

I have a (~'99) disco 1.21:1 "Q" case bolted to my LT85 at the moment. A disco case fits a defender fine, except that high and low are reversed on the shifter.

You will need a turbo with your setup. What ratio are the diffs?

[Lotz-A-Landies]

AFAIK all LT230s will bolt to any R380/LT77(S)/LT85/ZF (with spud shaft).

I have a (~'99) disco 1.21:1 "Q" case bolted to my LT85 at the moment. A disco case fits a defender fine, except that high and low are reversed on the shifter.

You will need a turbo with your setup. What ratio are the diffs?Ben

Nothing could be slower or more thirsty than a 3.5 carby V8! :D

My concerns were whether the change linkages etc will fit.

I am assuming the diffs are 3.54:1 same as the rest of the Defenders.

The plan is to build the D150 (http://www.aulro.com/afvb/projects-tutorials/138005-ikea-6x6d-anyone-have-allen-key.html)with a NA 4BD1 in the short term and get it rego'ed then build up a second 4BD1 (which I have) as a turbo engine with the oil squirters, new rings/bearings etc. Then swap over the engines.

Sounds like an O.K. plan or would you go a different path?

Diana

[isuzurover]

Ben

Nothing could be slower or more thirsty than a 3.5 carby V8! :D

My concerns were whether the change linkages etc will fit.

I am assuming the diffs are 3.54:1 same as the rest of the Defenders.

The plan is to build the D150 with a NA 4BD1 in the short term and get it rego'ed then build up a second 4BD1 (which I have) as a turbo engine with the oil squirters, new rings/bearings etc. Then swap over the engines.

Sounds like an O.K. plan or would you go a different path?

Diana

The perentie 6x6 runs 4.7 diffs, 1.1(or 1.2?) t-case AND a turbo.

I would suggest you don't try a 1.003 t-case and NA engine. You may even want to go to a 1.4 t-case with 3.54s. (probably the best option - especially if NA).

Many of us have shown that the NA engine holds up fine with a turbo and no oil squirters. I would turbo from the start, then you don't have to change t-case ratios after fitting a turbo.

[Lotz-A-Landies]

Thanks Ben

I will do a diff ratio calculation on Friday.

The turbo build up would be easier during the vehicle build up, no doubt about that, but was wondering about the 15% increase in engine size. But checking the NSW Transport Roads and Maritime site today. I find two things:

https://www.aulro.com/afvb/images/imported/2014/01/611.jpg

A GVM of 4700Kg takes the D150 out of the light vehicle mods.
The 15% rule has been replaced with a calculation based upon tare weight, allowing something like a 9litre engine. (Who would have thought the ex-RTA could be logical?)
Diana

[Terrain Vehicles]

As mentioned above, the LT85 is a stronger box, and I would much rather have that in the 130 than the LT77, but trying to make a Tdi fit a LT85 would have been a nightmare, so went with the 'keep it simple' option.

Another difference is the height of the box. When fitting the LT77, none of the original gearbox tunnel would fit, and we had to cut a chunk out of the seat base to get it in. It shouldn't really be a problem when going LT77-LT85 as the 85 will be lower. But be aware that you may need to change the tunnel.

My LT85 is now waiting to go in my 1983 V8 110 which has the 4 speed LT95 box. Hopefully that will be fairly straight forward...

[Freestyler]

Some measurments, the LT 77 is 358mm the bell housing is 305. 663mm all up. The LT85 is 385 and Bell is 284. 669mm. These were rough and the 6mm may be my error. Would be close enough though. I didn't think any V8 Defenders made it to Australia?? My father has a 1990 County with tht V8 and LT85 box. I did some calculations on the transfer ratios as I have been looking into changing the ratio in my V8 120 County to the same as a Disco. The different in engine revs was going to be about 440rpm Mine runs at 2600rpm at 100km with 33's on it. I am not sure what the rev range is of an Isuzu though?

[Lotz-A-Landies]

At least 2 Defender V8's made it to Australia as private imports, mine and the it's sister imported at the same time.

[Freestyler]

Dad's county was privately imported from south africa. It has the Defender style doors and a flat roof (not ribbed like an earlier countys like mine. ) It als has the split case LT85 and gemmer power steering box (6 bolt) and factory air. It use to have the 3.5 carbie engine. It is now a 4.6 efi.

[Lotz-A-Landies]

I did have a 4.6 EFI engine to fit but decided to go 4BD1 or 4BD1-T instead. The 4.6 is better off in the 101 whence it has gone.