Gu 4.2 engine braking

Submitted: Tuesday, Jan 29, 2008 at 21:12
ThreadID: 54017 Views:2216 Replies:7 FollowUps:6
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i have just traded my 3ltr for a 4.2 and after the first weekend have found the engine runs on down hill. i was traveling with a hilux and where the hilux would sit at idle the 4.2 would run up to 2,000 rpm. i was expecting much better engine braking than this.
is this normal or could something be wrong
Keith
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Reply By: desert - Tuesday, Jan 29, 2008 at 21:15

Tuesday, Jan 29, 2008 at 21:15
Sounds perfectly normal for the GU. The reason is the fairly marginal gearing that the Patrol runs. You'll find the Hilux and even the 3 litre are much lower geared.
AnswerID: 284383

Reply By: Michael ( Moss Vale NSW) - Tuesday, Jan 29, 2008 at 21:31

Tuesday, Jan 29, 2008 at 21:31
Ok no engine braking but it wont let you down!!! Michael
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AnswerID: 284389

Reply By: Bonz (Vic) - Tuesday, Jan 29, 2008 at 21:54

Tuesday, Jan 29, 2008 at 21:54
hmmm I would have expected more from a 4.2 also
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Reply By: Trevor R (QLD) - Tuesday, Jan 29, 2008 at 22:11

Tuesday, Jan 29, 2008 at 22:11
These will help matters. I have the 3.7 ratio reducing low range buy a further 85% over factory. You will have no probs going down slowly with these. Factory low gear is a tad high considering the highway diff ratio of the 4.2 IMO.

Cheers, trevor.
AnswerID: 284407

Reply By: Member - keith P (VIC) - Tuesday, Jan 29, 2008 at 22:13

Tuesday, Jan 29, 2008 at 22:13
sounds like ill order the marks adapters creeper gears.
cheers
Keith
AnswerID: 284408

Follow Up By: Truckster (Vic) - Wednesday, Jan 30, 2008 at 15:51

Wednesday, Jan 30, 2008 at 15:51
They are over rated.. perfect if your into comps, but you lose normal low range, which is handy for cruising around in the bush without having to stop each time you come to an obsticle to change ranges again..

Find someone with a set fitted, and go for a drive.
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Reply By: madcow - Wednesday, Jan 30, 2008 at 07:43

Wednesday, Jan 30, 2008 at 07:43
If you drove a DX you would find they are geared a bit lower than the ST.
AnswerID: 284455

Follow Up By: Tony - Wednesday, Jan 30, 2008 at 07:49

Wednesday, Jan 30, 2008 at 07:49
Thats a fact. Also I turn off my A/C when going down steeeep tracks.

Never had a problem with my 4.2 DX wanting to run away down hill.
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FollowupID: 549211

Follow Up By: Leroy - Thursday, Jan 31, 2008 at 10:38

Thursday, Jan 31, 2008 at 10:38
Are the transfer or diff gears lower?

Leroy
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FollowupID: 549443

Follow Up By: Tony - Thursday, Jan 31, 2008 at 10:52

Thursday, Jan 31, 2008 at 10:52
It must be the transfer gears Leroy, I think the diff ratio is the same.

About the only place I have used a bit of breaking as well is going down Hearn Spur to Wonnagatta River, and maybe on Billy Goat Bluff.
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FollowupID: 549447

Follow Up By: Leroy - Thursday, Jan 31, 2008 at 12:27

Thursday, Jan 31, 2008 at 12:27
It's all steep around there!

thanks......Leroy
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FollowupID: 549461

Reply By: Member - JohnR (Vic)&Kath - Wednesday, Jan 30, 2008 at 08:16

Wednesday, Jan 30, 2008 at 08:16
Keith, I found with oversized tyres on like 285/75x16 STTs on that even in low 1st I have had to drive with the brakes on on steep tracks. Never driven a 3 litre to compare in a similar situation. In the Pyrenees, I had people behind talking to me about the use of brakes. I remeber that Willem didn't need to in the same situation in his GQ.

The grearing isn't as low as it could be, that is for certain. On some climbing slopes I had to use more revs than optimal just to insure I was above stall speed.
AnswerID: 284459

Follow Up By: Member - MUZBRY (VIC) - Thursday, Jan 31, 2008 at 09:20

Thursday, Jan 31, 2008 at 09:20
Gday John
I was with Willem at the Pyranees and we went down some of those hills at breakneck speed. Just look at the teeth marks on the jesus handle.I bent my plate and had to lever it off with a tyre lever.
Muzbry
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