FJ62 On-road Off-road Performance is Jekyl and Hyde (1 Viewer)

[juano46]

Hi y'all,
I am a newbie to the forum but not a newbie to 60 Series cruisers. I have owned two FJ62s since 1995. My current cruiser is a 1990 with 168,000 miles and no rust. I have noticed a similar problem in both,namely, that the engine/trans don't work well together in 2WD high range. Throttle response is anemic, acceleration is pathetic, as if the trans is just "slushing" power away. Downshifting is a dramatic effort (pedal all the way to the floor) especially down to 2nd if there is a slow start-up. From a stop it's like the trans doesn't shift down to 2nd or low but starts out in third or shifts to third way to early; I have verified this with the manual shift. I live in Colorado and when driving above 10,000 ft it's as if the engine can't get enough air. It's like the ECU is wrong for the vehicle.
Ok, so now for the flip side: as soon as the cruiser is in 4wd low range the performance of the engine/trans is entirely different!! Throttle is very responsive, trans shifts appropriately, plenty of power above 10,000 ft. It's a whole new animal. What the hell is going on here? Is it the nature of the beast? Can any of you spot a problem, or can the high range performance be improved?
It's driving me crazy and it's a real-life problem because I don't want to give up that body style. I would appreciate your help. Thanks, John

 

[tclark]

That all sounds pretty normal to me!

 

[62LostInMn]

What size tires do you have and is it stock gearing?

 

[RockDoc]

X2 on what size tires? Have you checked to make sure the throttle and tranny kickdown cables are pretty tight?

 

[WJB4000]

I have the exact same feeling in mine and I absolutely HATE driving the thing on the highway because of it. If I hit any kind of incline at all, I can't make it up without manually downshifting into 3rd or 2nd (depending on how slow I'm going) because the trans won't do it by itself. It'll downshift into 3rd sometimes, but going down into 2nd gear trying to gain speed is nothing short of impossible. If I try to get it into 2nd without manually shifting, it will redline and go straight to 1st/freewheel and I let off quickly to not blow the engine and I'm back into 3rd. I don't know if my trans is starting to go or if the kick down cable is misadjusted? Any comments or suggestions are welcome. I have done a fluid change a couple times since last summer to see if I can get the fluid better since changing the seal between the transmission and transfer case. A lot of gear oil in there.

 

[MANUCHAO]

It's driving me crazy and it's a real-life problem because I don't want to give up that body style. I would appreciate your help. Thanks, John

Any comments or suggestions are welcome.

Sounds like you could benefit from a partial to full swap on the drivetrain..

Partial being a five speed manual tranny.

Full being an engine/tranny swap on either a diesel or gasser...

All think about on most trips is how smooth the highway ride is, yet how awesome and capable my rig is on the off road part of the ride......

 

[bigdaddychud]

My sons 62 is the same, if we hit a hill he goes down to 3rd, or he floors it and forces the kickdown. From my experience and forum reading this is normal for these engines.

 

[juano46]

What size tires do you have and is it stock gearing?

What size tires do you have and is it stock gearing?

My first 62 series ran stock tire size and stock gearing and I had it for 210k miles. My current 62 series has BFG 31x10.5 still on 15" wheels. The gearing is stock.
Let me know what you're thinking and why you are running a 4.88 rear end. Appreciate the help

 

[SteveH]

My FJ62 requires some flogging in the mountains, and manual shifting to prevent the 'designed by a GM fuel economy engineer' shift points from aggravating me too much. I also run the engine at 3500 RPM at times, in spite of the racket from under the hood. I figured if blow up the 3FE, it'll make a LS conversion make more sense.

I also run 31x10.5s on stock rims. It's just the nature of the beast - my '87 FJ60 was a slug, too. I think sea-level dwellers have little appreciation for an FJ62 at 10K feet, loaded with camping gear.

 

[juano46]

X2 on what size tires? Have you checked to make sure the throttle and tranny kickdown cables are pretty tight?

Thanks for bringing this up the throttle and kickdown cables. The answer is no, they haven't been checked and I will get that done. I have wondered about these two a possibilities so it's time to get after it. Thanks

 

[juano46]

Sounds like you could benefit from a partial to full swap on the drivetrain..

Partial being a five speed manual tranny.

Full being an engine/tranny swap on either a diesel or gasser...

All think about on most trips is how smooth the highway ride is, yet how awesome and capable my rig is on the off road part of the ride......

Hi MaNu. Yep, I have investigated swaps. I'm not handy with a wrench like many of you so i would have take it somewhere. I checked two cruiser specialists on the 5 speed swap. Low price was 7k plus plan for 20% overage and the other was 9k-11k with some overage. The crated 5 speed is meant for a diesel and so the gear rations for each speed are lower than what I'm running now and the OD is 1:1. i don't think that gets me where I want to be which is better performance for highway. As bad as my auto trans is there is plenty of low end.
The V-8 swap with matching 5 speed auto came in at 30k. In the 20+k range I can find a good 100 series, so the V-8 swap makes no sense unless I could do the work, which I can't. But thanks for bringing this up

 

[juano46]

So another thought on this is the ECU. If I'm not mistaken the auto trans in mine, the A440F was also used in the 91-93 80 series. I'm thinking I need to post on that forum to see if the early 80 series has the same performance problems. If they don't and the engine and trans are basically the same then maybe switching out my ECU for new model might make sense. If any of you are familiar with that vintage of early 80 series speak up. Thanks

 

[PortFJ62]

My first 62 I loved it, but could not stand the 3fe. It was fine around town but when driving through the mountain passes it was horrible especially loaded down with armor and gear.. V8 is the game changer.

 

[juano46]

My first 62 I loved it, but could not stand the 3fe. It was fine around town but when driving through the mountain passes it was horrible especially loaded down with armor and gear.. V8 is the game changer.

Thanks, I just looked at your website and I'll give you guys a call to see if a swap makes sense

 

[NCFJ]

@PortFJ62 is correct that a V8 is a game changer, as are some of the diesel swaps. Obviously, this path is a much larger commitment.

I would try the fixes mentioned here in the thread before going too crazy with fixed involving swapping out drive line components.

 

[PortFJ62]

Once your pass the cost of the swap you will have more power, better fuel economy, easier to work on, cheaper and available parts anywhere in the country. It is the future for these trucks survival in my opinion. Diesel swaps are nice but rattle those trucks and are loud. 4bt anyway.
Sorry Mike.....

 

[WJB4000]

I'm contemplating a 5.3/4L60e swap in mine. I'm confident I can do it myself, but just scared since I've never done a swap like that before. I am a mechanic by trade so that's not what scares me, it's just the unknown that I'm worried about. Ya know, getting into the swap and then getting frustrated with it and then not having a running rig. Sorry, just rambling now and trying to talk myself into keeping this thing instead of trading it off for something else I've got my eyes on.

 

[MANUCHAO]

Sorry, just rambling now and trying to talk myself into keeping this thing instead of trading it off for something else I've got my eyes on.

The heart wants what the heart wants.... no point on denying it.....

 

[Michael Hanson]

Hi, I'd check the kick down cable first as suggested.we drive a 1988,1989,1991 all similar drive trains. When our 1991 slowed down,acted up, it was our transfer case that needed rebuilding. It was just worn out. Mike

 

[AirheadNut]

My FJ62 was an absolute dog on the highway, unless it was dead flat. I once hit nearly 80mph running 31's, but that didn't last long. Any hill required a downshift to 3rd. Engine and trans both in great shape (~145k original miles). It was so slow accelerating that my LJ78 with a 97hp diesel felt fast.