Thread: Replacing a 3-Speed Auto with an LT85?

The gearstick for the LT85 will be in the wrong place for the Rangie and the ratios in your 727 LT230 will be 1.003:1 way to high for the manual box. The Santana LT85 are an expensive box to repair.

The ideal fitting for your Rangie is an R380/LT230 out of a V8 Disco 1.

Get a proper lt85, not the split case one. They come up time to time as they were fitted to V8 Counties. The gear stick issue isn't too big a problem.
As for the ratios, there is nothing wrong with them. The LT95 had a high range ratio of roughly 1:1, same as your transfer case and both have a 4th gear of 1:1. The only difference is the LT95 has a lower 1st gear and the LT85 has a 5th gear.
Considering my father only used 2-4th in his rangie for normal street driving half the time, I don't think the 1st in the 5 speed box will be an issue.

Your ratios with an LT85 and 1.003:1 LT230
........... | High | Low
1st Gear 12.96:1 42.90:1
2nd Gear 07.74:1 25.63:1
3rd Gear 05.10:1 16.88:1
4th Gear 03.55:1 11.76:1
5th Gear 02.82:1 09.35:1

High Table
Gear 1st 2nd 3rd 4th 5th
Speed
10 KPH 934 558 367 256 203
20 KPH 1867 1116 735 512 407
30 KPH 2801 1673 1102 768 610
40 KPH 3734 2231 1470 1023 814
50 KPH 4668 2789 1837 1279 1017
60 KPH 5602 3347 2204 1535 1220
70 KPH 6535 3904 2572 1791 1424
80 KPH 7469 4462 2939 2047 1627
90 KPH 8402 5020 3307 2303 1831
100 KPH 9336 5578 3674 2559 2034
110 KPH 10270 6135 4041 2814 2237
120 KPH 11203 6693 4409 3070 2441


Your ratios with a V8 D1 R380
Ratio Table
.......... High Low
1st Gear 14.37:1 39.04:1
2nd Gear 09.22:1 25.06:1
3rd Gear 06.04:1 16.42:1
4th Gear 04.33:1 11.76:1
5th Gear 03.17:1 08.61:1

High Table
Gear 1st 2nd 3rd 4th 5th
Speed
10 KPH 1035 665 435 312 228
20 KPH 2070 1329 871 623 456
30 KPH 3106 1994 1306 935 685
40 KPH 4141 2658 1742 1247 913
50 KPH 5176 3323 2177 1559 1141
60 KPH 6211 3988 2613 1870 1369
70 KPH 7247 4652 3048 2182 1597
80 KPH 8282 5317 3484 2494 1825
90 KPH 9317 5981 3919 2805 2054
100 KPH 10352 6646 4355 3117 2282
110 KPH 11387 7310 4790 3429 2510
120 KPH 12423 7975 5226 3741 2738

and finally the LT95
Ratio Table
............ High Low
1st Gear 16.91:1 47.85:1
2nd Gear 10.18:1 28.80:1
3rd Gear 06.28:1 17.75:1
4th Gear 04.16:1 11.76:1

High Table
Gear 1st 2nd 3rd 4th 5th
Speed
10 KPH 1219 734 452 299
20 KPH 2438 1467 904 599
30 KPH 3657 2201 1357 898
40 KPH 4875 2935 1809 1198
50 KPH 6094 3669 2261 1497
60 KPH 7313 4402 2713 1797
70 KPH 8532 5136 3165 2096
80 KPH 9751 5870 3618 2396
90 KPH 10970 6603 4070 2695
100 KPH 12189 7337 4522 2995
110 KPH 13407 8071 4974 3294
120 KPH 14626 8805 5426 3594

Work out for yourself what you want for your current engine.
At 100KPH on the LT85/1.003 LT230 mostly you'll be at or below your max torque in 4th, I'd think that would be overgeared.

Red RPM figures are above red line on engine

The figures have been worked out on 29" tyres and 3.54 diff ratios,
if you have larger tyres your figures will be worse.
IMHO you'll have difficulty in driving at walking pace unless you slip the clutch or drop to low range.

Phew, there's an answer for you! Thanks for going to the trouble.

I was hoping that someone had done the swap in a Rangie already as I know these things are never simple.

Somewhere else on the forum there is a measurement of an LT85 with bellhousing, which is oddly the same length as the Torqueflite and adaptor. If this is correct, then it would fit without having to move the transfer and associated bits. I think the R380 is longer?

And a quick guesstimate looks like the gearstick would come up about where it does on the LT95 . . . or under the dash somewhere.

The transfer would be rebuilt so the gearing could be changed anyway, and Ashcrofts sell all those bits.

As usual, what the factory did is what's easiest, and I do have a few LT95s around. What I would like is an LT95 that's rebuilt since that's just another annoying job I'd like to get out of this time around, but, alas, it seems to be all 5-speeds these days.

That 1.003:1 ratio LT230R is sought after by people running diesels and needing longer legs. I run one in my 4BD1T powered rangie. You should be able to sell it or even swap it for whatever ratio case you want.

The long-stick gear position of the LT85/LT95 should be the same as defender R380's and LT77's. The later rangie and all discos used the short stick behind the transfer-lever. You'll have to modify the centre console lots to make that fit.

Yes, lots of modifying. I figured that. I was just hoping someone had done this as it looks like the LT85 would fit right where the automatic was, which would be nice as I just spent several hundred dollars on getting the rear driveshaft rebuilt!

Your turbo diesel Rangie sounds very, very nice . . .

With a Disco 1 R380/LT230 combination, the D1 prop shafts will fit your RRc, there has never been an LT85 RRc so if the LT230 is fore or aft of the standard LT230 position you will have to have special prop shafts made up.

If you use the D1 V8 R380 stuff like transmission brackets etc, everything will line up with the mounting holes already in your chassis.

IMHO the D1 V8 R380 conversion is the strongest, simplest and most straight forward conversion. There are plenty of D1 V8s being wrecked.

For the clutch you merely get the clutch pedal, brackets and clutch master cylinder off a manual 1985 RRc and you will find that the mounting on your firewall is already there with just a blanking plate.

Not sure, but I think there may be a difference in the brake pedal between the auto and manual '85 cars too.

Will check the parts manuals when I get home to see if there are differences between the rear prop shaft in the various RRc/D1 models.