I have a 1985 4x4, 22re, 4spd auto with stock gearing of 4.30 (from what I was able to decipher from stamp on firewall) and 30" all terrains. I recently built a custom chassis mounted camper on the back that roughly weighs 1,200lbs dry. The truck and camper really struggle on big grades and I generally get stuck in second gear barely going 35 on 6% grades. I'm wondering if changing up the gearing to 4.56 or 4.88 would help out on long highway grades? Love to hear from anyone who can give a little insight

 

Well, you've probably overwhelmed the GVWR at this point...I really doubt going to a small jump of 4.56 would be notable. A 5 speed would definitely help for sure. I think 4.88s would be your best as 5.29s would have you screaming on the freeway (really the 4.88s could too).

 

A higher gear ratio should help get you into the power band when you upshift. Your basic problem is that you're not making power at the lower RPM when you shift. I'm pretty happy with 4.88's and 31's in my carb'd '85, usually hauling about 1000 pounds of gear. Other mods I've done that could be helping me are LCE's header and their 30 pound flywheel (https://www.lceperformance.com/High-...-p/1051015.htm). With that said, I'm shifting into 5th around 4k rpm and 75 mph. Nobody really needs to go that fast in a '85 toyota pickup, so going even higher than 4.88's might not be a bad idea, especially if bigger tires might be in your future.
Edit-didn't notice you have a 4 speed...

 

Thanks for the input! I decided to go 4.88. I ordered from East Coast Gear Supply and they were super helpful. Hopefully I will have everything installed and ready to go in the next week or so.

 

That camper is awesome, can you share some more details? Pictures please!

 

Yeah! For sure

 

I welded the structure out of light gauge steel. The siding is all glued and riveted 040 aluminum which I painstakingly hand bent with a station bender. Its chassis mounted, spring up front hard in the rear. Nice little kitchen and sitting area, plenty of storage and sleeping over cab. Oh, and 2" xps foam throughout so it stays super comfortable. It's been awesome and I plan on building another one for my tundra next year.

 

Highly recommend EGCS, good to hear you had a good experience!

 

I got both front and rear difs in and I'm super happy with performance driving on and off highway (especially on grades). Only issue I have now is with speedometer calibrator - when dash says 70mph gps says 55. I have been reading some threads but can't seem to find anything related to my year and make. Any ideas I how I make the correction or point me in the right direction?

 

I had these guys build me a little box that goes between the cable and the transmission. As I recall cost seemed reasonable and turnaround was very quick.
https://www.speedometerserviceportland.com/