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Old April 18th, 2016, 08:05 AM
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Chris Snyder
1994 D90 ST #614 | '95 RRC TWR
Join Date: Feb 2006
Location: Newburyport, MA
Posts: 1,532
I ran into this when I put my 4.10's in as well. Freaked me out the first time it happened as I was passing someone and the engine cut right out. Took me a bit to realize what was going on. I've just left it as is for now as I really shouldn't do 75-80 in my truck anyway. But 4.43's and a top speed of 65mph would be tough

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Old April 18th, 2016, 08:59 AM
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72 + D1 drivetrain
Join Date: Sep 2006
Location: Colonies
Posts: 7,543
Cross check speed with GPS....and get a beer to celebrate sorting this out

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Old April 18th, 2016, 09:51 AM
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John B.
1991 Defender 90, 200TDI
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Join Date: Sep 2003
Location: Calgary
Posts: 7,901
Originally Posted by evilfij View Post
There is very limited differences between the gear ratios of a 300tdi and a V8 R380 (so it does not matter much) and, if I had to guess, your speedo and tach are off slightly and you have a V8 r380 ratio trans. Oh and the input shafts are different (pretty sure need to check to be 100%) so that also makes me doubt it. Anyway, read the number on the side of the box and you will know what you have. In any event, get the chip (make sure it is the right one), report back.
When rebuilding a box, you can do most things. The V8s have a higher 1st and 5th. These can be mixed and matched, as desired, during a rebuild. If you have a strong TDI, using the lower 1st and the higher 5th gives a wider gear range.

You can use the TDI input shaft on the V8, but it requires a special pilot bushing and clutch.
Pissing people off on the "net" since 1983.

Land Rover. Turning owners into mechanics since 1948.
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Old April 26th, 2016, 08:50 PM
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Ryan Noonan
1994 D90 NAS #159
Join Date: Nov 2015
Location: Los Alamitos, CA
Posts: 52
So I ordered a 1990-1994 RRC 3.9L PROM (PRM3652) chip on eBay for $100 from Land Rover Dallas and I swapped it out today.

Followed the directions at:

It was easy peasy.
Here's the ECU board once I swapped the chips:

Click image for larger version

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She runs like a champ now. Feels like more changed than just the lack of speed limit (which is confirmed gone). She accelerates all the way up to 70 mph with all the throttle response I need in the first 1/4 of throttle.

Overall very happy with the decision to go with the 4.43 R/P since the only daily driving I do is local streets and not long stretches of highway everyday... Starts from a stop in 2nd gear no prob. Only highway I do is to/from the trails and like I said before, I'm never really in a hurry... At least now I've got that extra 5-10 mph to oomph past a truck on an uphill grade when I need it... And when I don't, at least I'm not bouncing off the speed limiter when I'm cruisin at 65 (89 indicated)

Perhaps a VDO Speedo upgrade is my next project.

Thanks everyone for your help!

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